Mercedes SRS Fault – Fix

 

Here is a way to deal with a common SRS fault that lies within the seat pad of the Mercedes E Class (W210). (I am sure also similar for other models)
The service history of my current E Class W210 shows repeat visits over 10 years for this specific SRS problem and I would like to share with you the ins and outs of it all (each visit cost the previous owner £220 for the cure/pleasure – only to have it return again almost every 18 months to 2 years during ownership)
If the red SRS lamp on the dash is accompanied by the orange airbag lamp next to the transmission shifter is lit, the fault is commonly connected to the passenger seat sensor. As I imagined the previous owner had always a rather ‘cuddly’ passenger riding shotgun, the seat would have taken a pounding, the flopping into the car was probably the most damaging to the seat related parts I am about to describe.
HOW IT WORKS
Layered within the seat base skin of the passenger seat, there is a complex contact matrix (like a foil printed circuit – looks like an aerial view of a maze) that senses if the seat is occupied (a bum on it) and in most cases with post face-lift models, also auto-senses the proximity of the MB child seat. The former sensor circuit is used to switch off the passenger air bag if the seat is unoccupied, the latter is to used to switch off the passenger air bag when a MB child seat is fitted on the seat. Understanding that the weight may fool the occupancy sensor to thinking an adult bum is on the seat, the child seat detector overrides this and signals the Air Bag Control Module to turn off passenger side airbags. When it does this, the orange Air-Bag off transmission LED illuminates showing the system is disabled and its safe for baby to travel.
On cars pre face lift, without auto child seat detection, the connection from the seat occupancy sensor is connected directly to the Air Bag Control Module and operates just as a simple switch, changing the potential of the signal line to the module when sat on. Post face lift set up is far more complex. There is an electronic box inside the seat base that forms part of the sensor matrix, the ends of the wire ‘maze’ are connected to this and it converts the status of the occupancy detector into a CAN output signal that is piped to the Air Bag Control Module (as a PWM signal) An over simplistic way to imagine this, is to think of it as a pulse, like a heart beat at a fixed rate. This beat is detected by the ABCM (Air bag control module) when the seat is unoccupied and turns off the air bags on passenger side. Once the seat is sat on, the electronic box in the seat changes the frequency of the pulse which is again detected by the ABCM to turn the passenger bags on. The other function of the electronic box within the seat is to auto-detect the presence of the MB child seat, this is done by using RFID (radio frequency identification) working in the same way as the detection alarms at the doors of music shops etc. The RFID token hidden in the child seat is detected by the seat matrix (antenna) and the electronic box then gives out the all important seat unoccupied/child seat in place PWM CAN signal to the ABCM turning off the passenger bags and illuminating the advisory air bag off light.
HOW TO FIX IT
There is a yellow connector beneath the seat, this houses all the connections to the seat pad sensor and links its signals to the ABCM. It is very common for the wires to and around this connector to break (seat-side) as they are very fine conductors indeed and this is compounded by a slight design flaw, in that the cable that enters the seat base to the matrix is tie-wrapped to a metal seat component which in turn causes a stress fracture along the wire length where fixed. So the first thing to check is the connector and it wires (best to remove the seat) If the break is suspected within the depths of the seat base, then it has to be stripped to repair/replace the parts. (This is where the repeat £220 bill from the agents came from!)
Understanding that this is a life saving safety system and the owner may wish to entrust the correct remedial work to a dealer or do it himself with the correct MB parts, there exists however ways to get around this common failure, it is up to you as a reader/owner to make up your own mind if you wish to follow and act on this information. I would not recommend that any of the following solutions be used if the vehicle is or could be used carrying young infants in the front seat, but worth considering if you are grey and old (past it) like me. I have attached a useful wiring diagram of the SRS components so you can identify what’s what on the connector etc. But if you can’t fathom the circuit, then my polite advice to you would be to not mess any further!
So you are still with me…
If your car is a pre face lift, with a non auto detect child seat, then the seat pad matrix can be simply linked out on the yellow connector under the seat. This will signal to the system that someone is sitting in the seat all the time and cause the passenger airbag to be permanently ‘live’ whether anyone is sitting in the seat or not! (In my view better than not working at all) This is a great fault finding tip if nothing else, as it proves if the fault lies within the seat pad, as the SRS lamp and air-bag orange lamp on the transmission will extinguish immediately the ignition is turned on (without a star reset!)
A later auto child seat detecting, post face lift, later  E Class W210 model, cannot be ‘linked out’ in any way sorry!  It needs a CAN keep alive signal to the ABCM to signify that the system is fault free (default seat unoccupied signal) so any fault occurring in the wiring or seat matrix resulting in the PWM output failing will deny the function of the passenger airbag by default and raise the SRS dash lamp along with the orange air bag transmission mounted indicator. So strip out the seat and remove the leather etc etc…… OR buy a magic box from China from the large online auction sites. This seat sensor emulator box, usually around £15 delivered to your door, provides a seat occupied PWM signal output that once connected, fools the ABCM into thinking all is well and that there is a bum on the passenger seat. There are 3 wires to connect, colour for colour those that exist under the seat Brown, White and Red on the yellow connector. This resets the SRS lights as before on ignition power, without a star reset.
Just for information the China emulator box contains a programmable PIC chip that emulates exactly the signal that would be given from the MB seat pad matrix. Make sure you get the correct one for your correct model if ordering, as there are a couple of types of ABCM used through model years.
emulator
So hopefully this has been useful in explaining how the SRS seat sensor system works and that from this you can get an idea what is ahead of you. I tried to find out information like this and its a little sketchy and hard to place so maybe its of some use in your fault finding, diagnostics and resulting repair. The diagram below is especially useful !
SRS Electrical Diagram:
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118 thoughts on “Mercedes SRS Fault – Fix

  1. The other day a wire shorten under the dashboard behind the glove box. It looks like I have to take the dashboard out to get at the wires that go through the fire wall.

    Looking at the dash it is one lump any pointers on how to remove it. Even the glove box is moulded into it.

      1. Hi Grant,
        The fuse box under the hood connects through the bulkhead to the wiring loom, there is a chance the wire is damaged in the fuse box (it may have even taken a fuse out in here) Most of the power distribution is done here check the wires to the rear of the connection/distribution fuse and relay board. Grab a torch and have a good look – and smell around and see if you can spot anything.

        The dash is in 2 halves the upper and lower, just as you say the glove box is moulded into the lower half. There is restricted access under the dash by the hood release, under the plastic under dash cover, but if you have AC expect this to be a little more crowded. As you suggest it is quite a large job to remove the dash and I would need to be 100 per cent that’s where my problem lay before venturing forward. Have a good look in the huge fuse box in the engine compartment to be double sure it cant be put right from in there. I have searched high and low and cannot find even a parts explosion of the dash to assist you in how in all comes apart.
        All the best
        Steve

      2. Hi Steve

        I got a local auto electrician to come over and he spent most of the day fixing the loom, without taking out the dashboard.

        The fault was a worn wire just behind the light switch on the far right of the dashboard. The loom passes between two metal plates that support the steering column and they had worn through one of the power wires going to the instrument cluster. This resulted in a hot wire between the fuse board and this point which in turn melted a few critical wires around it before the fuse blew.

        The fuse box is actually quite spacious and enabled us to unplug the loom from the back of the fuse board, cut about 10 cable ties behind the dash and pull the loom back to the centre space behind the radio. Replace the wires and re-wrap the loom and refix it.

        Alas we didnt have time to fix the loom behind the steering column so this is going to be done this Sunday. We also still have the brake lights on all the time.

        Update to follow.

      3. Hi Grant,
        Be interested to know exactly what part of the loom wore through, I thought most of that under there was cloth wrapped and in some cases even foam jacketed. Was the wiring disturbed or had its routing been disturbed, ties cut etc. Sounds like it should be noted as a weakness if its as it left the factory.
        All the best
        Steve

      4. Dear Steve

        Apologies for the delay in replying but we have just managed to track down all the errors and fix the van this afternoon after 3 days solid.

        The initial fault was a small fire under the dashboard which filled the cabin full of smoke. The van was drivable, but the brake lights were always on ans it blew a 7.5amp fuse in the bottom left of the fuse board.

        In short, I called an auto electrician (Brian Dolan) who works in West London and we both proceeded to remove as much of the ancillary items from the dashboard as we could including the floor liner.

        The cause: We think the main short was on a sub loom that goes to the instrument cluster back to the 28 pin connector on the fuse board. The cable appears to be as factory fitted and it wore through the insulation on the steering column support. The wire was blue / black and it shorted to Ground which burnt all the insulation off this wire right back to the fuse board before the 7.5 amp fuse blew. Two other wires in the same loom were melted to this wire so we ended up replacing three wires by disconnecting the multi way connectors from the fuse board for this loom and pulling them back through the bulkhead to the radio hole. (This sounds hard but the back of the fuse board is big enough to get your hand through) We then pulled the 2nd part of the same loom from which feeds the ignition, lights and instrument cluster through towards the right of the van so we could fix the length that runs from the radio hole and behind the instrument cluster.

        We picking the whole loom apart, replaced any burnt wires and re-wrapped it in a fabric wire tape. Make sure you re cable tie it back in place to stop it happening again, this isn’t easy but worth doing!!! Also get some auto fabric wire wrap tape to protect the loom!!!

        The next fault that was either connected or had occurred some time before. We found more burnt wires from the brake pedal switch back to the fuse board. These wire go from the brake pedal switch, behind the clutch pedal, over the central drive tunnel and into a plastic protective channel that goes round the passenger foot well and up behind the glove box and through into the fuse board. This fault was causing all three brake lights to be always on.

        These wires were burnt every so often and we couldn’t see one place where a short had occurred, it seems as if they just got too hot in places. Two wires were mainly burnt (the ones going to the brake pedal switch) so we ended up replacing these wires from the brake pedal switch back to the fuse board. These wires went to a 6 way (I think, I was getting tired by then!) in-line connector that was also on the fuse board.

        All in all the van is now fixed, but we cant say if the two wiring issues are related or one occurred before the other. My gut feel is they are linked but we cant see an obvious explanation.

        The electrician had access to Autodata so we could see the wiring schematics which really helped to make sure no random control units were in play half way along a loom. In this case the W639 seems to be controlled by a SAM unit attached to the fuse board that doesn’t need programming and seems to be standard on all models of Vito however all lights, brakes etc go through this unit.

        Regards

        Grant

      5. Hi Grant,
        I may document this in a post as to be honest if those wires can wear through the problems you have had can be avoided with a little extra insulation at the accessible end! Thanks for the great report and I am glad that its now sorted.
        Keep in touch,
        All the best
        Steve

  2. Hello, I have a question for you and hope that you can help. I have a 1999 Mercedes E Class Turbo Diesel ( W210 ) I have used another emulator that has switched off the passenger airbag light off on the centre console but the SRS light on the dashboard remains iluminated. My diagnostic scanner states that the voltage on circuit (15r or r15 sorry can’t remember which) is either too high or too low. Can you advise whether your emulator would solve this problem?

    Kind regards

    C

    1. Hi Chris,
      There is a chance the device is not connected correctly, the wires are vey fine and best soldered. Obviously the emulator is working of a sorts because it is clearing the passenger lamp. There could be another cause holding on the SRS lamp. Have you tried resetting the codes on the SRS system? this may need to be reset if there was another associated fault, circuit disconnection or circumstance flagging the lamp, eg removing the speedo console and turning on the ignition will cause an SRS activation that can only be cleared with a suitable tool. A basic EODB reader will not probably have access to the SRS, ABS system for resetting so this may need to be done with a Mercedes specific tool. Once this is cleared it may stay off!
      Hope this helps.
      Best regards
      Steve

  3. Hi Steve,

    I had a great experience with a Mercedes specialist on my 1999 W210. They charged me 72 euro and cannot find a fault but alas the SRS light remains illuminated. On the first scan they couldn’t access the SRS control unit so luckily I had a spare one which they then retested using diagnostics they said that the unit passed but the problem is with the emulator under the seat so if I pay another 72 euro they will retest the car. Can you share any ideas on what I can do to fix this problem myself? I have very little to zero confidence on Mercedes here in France.

    1. Hi Christopher,
      Do you already have an emulator box under the passenger seat? If so it sounds like it has become disconnected somehow or is faulty.
      The emulator is an aftermarket device that connects to the wires normally connected to the seat pad switch matrix. If you do not have an emulator then the most common problem is the seat switch matrix in the seat base. The most common fault is failure of the seat pad wiring or the thin wires that connect to it and pass through the upholstery to connect to it.
      Let me know if you already have the aftermarket box, if you don’t you need to get one!

      Regards
      Steve

      1. Hi Steve,

        Thank you for the reply. Yes there is an emulator under the seat and the garage were trying to imply that the emulator was blocking them from scanning and resetting the SRS unit. I find this hard to believe and did ask them why they did not unplug the emulator and retest anyway that’s another story. If I unplug the emulator everything works fine in the sense that the passenger airbag light off remains off but the SRS warning light on the dash remains on. Sadly this has been an ongoing problem and being in France doesn’t help!

      2. Hi Chris,
        With regard the passenger airbag lamp on the selector console, if this is not illuminated when the emulator is disconnected and the original seat pad wiring reconnected – the fault could be elsewhere.
        The standard seat pad fault is that the SRS lamp in the binnacle is on with the airbag orange lamp on the selector console. You would need to re-attach the seat pad connector plug once the emulator was taken out of circuit to see that fault light combination, and not leave just it disconnected. There is no SRS reset required for seat-pad occupancy faults – they clear automatically when the fault is rectified. Seat pad faults can be intermittent, I have one on the C200 that flags SRS occasionally on a really hot day when the sun has been shining on the seat.

        It does sound as if their reader cannot access the SRS system, its more likely its unable to due to its type or even that they do have the older 38 pin adapter !! Access to a control module cannot be ‘blocked’ by an input. Think about it, if a fault existed on an input (SRS component) how could you find out where the fault was if the control unit was blocked from being read…

        If once you reconnect the the seat pad wiring and the SRS fault lamp remains without the orange airbag lamp on the selector console then the fault is most probably elsewhere. Now you need a compatible code reader! The Autel Maxidiag MD802 will do the job, (So will the Maxidiag Elite MD702 if you can find it, less models covered and a bit cheaper) it reads right down to the specific component at fault, once you have rectified it the same device will clear all SRS codes. As a DIY tool its a good investment as it will do you for all engine, transmission and control electronics. It would be a worthwhile investment as it does many other cars too. get money back by reading/clearing friends cars! Depending on the model year and your type of diagnostic connector you may need one of these:
        It would not take long to rack up the value of the reader with inconclusive code reads and unnecessary work – better to do it yourself and a great tool for the drawer!

        Hope this helps, all the best
        Steve

      3. Hi Steve,

        Thank you for taking the time to reply. I may have a solution and will update next week. I do have a scanner I’m using a foxwell NT622 but it states that the SRS control unit passes every time I scan.

      4. Hi Christopher,
        I would look for a debris in the seatbelt clasps if that were the case. Give them a good clean inside as best you can (vacuum and blunt table knife) they get all sorts inside! There is a micro-switch in here and it is known to give problems and intermittent SRS lamp when it gets choked with crumbs/sand etc. (Even give it a blast of electrical swich cleaner). It forms part of the seat occupancy circuit. There is a chance that as this is hard wired, it does not flag a fault on the controller (This was the case on older E124 anyway!) Well worth a look as I had this on friends later 2001 E Class W210, though I really cant remember if this was a problem with the buckle/stalk wiring, which you could also check out as well.
        Regards
        Steve

      5. Hi Steve,

        Thanks for the advice. Looking at the clips there doesn’t seem to be any electronic connections running from them it might be because my car 1999 E300 Classic I have tried cleaning up the seat belt clips a few times before and nothing changes but will give it another go! Have a great weekend.

  4. I tried to follow the instructions on my 1995 c220 and it worked for a while. But the light came back again mine switch has only 2 wires. The truth is that your information is very very helpful keep it up and may God bless you

    1. Hi Webster,
      I would look carefully at the seatbelt clasps, they have a micro-switch inside and form part of the occupancy circuit. This switch gets corroded with all kinds of sand, dirt and grime that falls into the buckle. Use a long brush and vacuum the grime out and clear the debris. Then use a quality switch cleaner sprayed into the clasp working the latch with the seatbelt for a while. This may be your issue and was quite common of the era, especially in the S class.
      Regards and thanks
      Steve

  5. Hi Steve

    I got in my Merc Sprinter Van (2012 plate) this morning drove around the block to my garage to unload and then when I went to leave the SRS Restraint warning was showing on my dashboard. This has resulted in no lights,brake lights, indicators, radio, sat nav etc. My dealer is 50 miles away from where I live and cant see it would be legal to drive this distance for a repair! any advice please. Regards Andy

    1. Hi Andy.
      It sounds like you have lost a supply to the electronics. You will need to check all the fuses in the box next to the bonnet hood release, also main fuses under driver seat access panel.

      Have you by chance caught the interior lights in the load area? Often these can short to the chassis taking out a fuse that supplies many things.

      Let me know what you find.

      You may find these links handy: http://www.sprinter.net16.net/fuses/ and http://www.mbsprinterusa.com/files/manuals/2013_Mercedes_Benz_Fuse.pdf

      All the best
      Steve

  6. Hi Steve
    I have 2010 Vito 115 automatic.
    Which all of a sudden has 2 ESP faults, and the check engine light is on as well, they van is i Limp Mode as well.
    The tester says it is the gas pedal and and oil sensor, they were both replaced but the faults remain.
    Would you have any clue what would cause the errors or how to fix them?

    Thanks

    1. Hi Rasmus,
      If the 2 ESP faults are the ABS light and ESP lamp then there could be a few things to check. You will need a specific Sprinter OBD test tool to get the correct codes as a generic code reader will mislead you as it sounds it has done so far. The most common problem is with the rear brake lamps or the pedal switch faulty above the brake, both are a cheap fix.

      It could also be the clock spring in the steering wheel, the wire that carries signals from the steering angle sensor to the EUC/ESP unit, however if the brake switch or bulbs do not cure the problem I would suggest to take the van to a main dealer or at least a good independent garage that has the correct diagnostic tool for Mercedes Sprinter and get them to tell you the problem. It will save a great deal of time, money and frustration in the long run – replacing parts as a guess!

      Hope this helps a little.
      All the best
      Steve

      1. Hi again

        Thanks alot for your help, i will investigate further, as i know the right tail lamp have been acting up with a blown bulb warning now and again.

        Thanks again!

  7. Hi Rasmus
    I live in Argentina.
    Sorry for my English.
    I have a 1996 W210 E320.
    I disassemble the instrument cluster to change several lamps and then re-installed.
    After this,the ASR lightcomes on for aprox. 50 seconds and then turns off. I can fix this problem whitout special tools? The ASR is working OK when the light goes out?
    Thank you.

    1. Hi Pablo,
      I doubt this issue is connected to the instrument cluster work you have done. It sounds as if you have an issue developing with the ASR pump and it is taking some time to reach pressure. It is common on early W210 models to suffer with this problem. It is usually caused by poor motor performance from the pump. Cause is usually bad or worn electrical pump motor brushes. Have a read here: for a little more information on this problem.
      Obviously this is just a good guess as I can’t see the vehicle to diagnose it properly. I would get a good second opinion before starting work.
      Best regards
      Steve

      1. Hi Steve:
        Thanks for you quick response.
        Sorry. Made a mistake. Is not de ASR light. Is the light of SRS or Airbag, which is stay on for two minutes and then turns off. Regardless if the car is hot or cold.
        Best regards.
        Pablo.

      2. Hi Pablo,
        No problem. The issue you have is again unrelated to the instrument console repair. The most probable cause is one or both of the front seat belt buckles. Inside the floor mounted seat belt clasp there is a small contact switch, if this has sand, debris, dirt or drink spill in there it will give a bad connection. This seatbelt/occupancy signal is read by the SRS controller at ignition on and if it does not get the expected voltages back from the buckles it maintains the SRS lamp on the dash for approximately 60 to 90 seconds. You will have to carefully clean them out with a stiff paintbrush and vacuum cleaner, then spray electrical contact switch cleaner into the buckle aperture while latching and unlatching the belt. If this does not work, you will have to identify which front seat buckle is faulty and replace it. This was also a problem on the S class of the same model era.
        Best regards
        Steve

      3. I will try. Thank you so much.
        Also since dissamble the instrument cluster,stopped working the fuel gauge. Any idea?

      4. Hi Pablo,
        You must check the connection of the multi-connectors on the back of the instrument cluster – it is easy to damage the pins if inserted incorrectly, especially so wit the latching mechanism. It is possible that you think the plug is inserted and latched correctly but actually it is only half way connected. Remove it again and be 100 percent that it is fully plugged in and latched. See detail of a similar multi-plug here: More info on the connector latch if you don’t have it – here.
        Do not turn on the ignition with the instrument cluster disconnected as you will trigger an SRS hard fault and permanent SRS lamp. This will then have to be reset with the dealer tool.

        All the best
        Steve

  8. To Steve ball
    I have a sl320 sportline the seats will not lock back and therefore will fail the mot
    Can you give some advice please.

    1. Hi Harry,
      First motor the seats forward a little and alter the rake of the back rest, then make sure the seat belt reels are fully retracted (pull fully out, and the smoothly control the rewind to fully-in position) Now fold the seats forward and try the latch mechanism again. Do you have a chime when the car is driven, signalling the seats are not locked back?

      If this does not work, the release/latch mechanism is bowden cable operated (like a push bike brake cable, from the handle to the latch) and may have lost its securing clips (though they usually latch ‘locked’ back and not unlocked) You may have to remove the seat bolster to look at the issue from the inside, this is reasonably straight forward and is nicely described here. Once the bolster is removed you can get an idea of what is going on, it may even be a lack of lubrication on the latch.

      I hope that is of some help,
      All the best
      Steve

  9. Hi there,
    I have mercedes c180 w202 1999. I was driving all of sudden srs light came on. Went to my local workshop, then he put a scanner and got this code: the coding for the digital crash output to control module. He does not know what it is? Will this simulator fix the problem?

    Thanks
    Mohit

    1. Hi Mohit,
      If the code is the 9030 code, it is with regard to the tele-aid system. If you no longer subscribe to this, it can be removed and ‘coded out’ by a Mercedes Dealer using the Star System. If you have never had Tele-aid option, then one of the air bag components is being read as coded incorrectly by the control module. This can be caused by a long period of battery disconnection (In storage), corruption of the coded device or a possibly fault in one or the other of associated components. You should first attempt to clear the code using the correct diagnostic tool, not all tools/OBD readers can access the Mercedes Air Bag controller. Often once this code is cleared the fault will go away as mysteriously as it came.
      Best Regards
      Steve

      1. Hi Steve,
        Thanks for the info. The actual code is A35/8 (tele aid control unit).
        Yes, the battery was flat when we came back from our holidays, I had to jump start it. But the srs light came on the second day. I rang Mercedes, they are asking for $250+gst to diagnose. I have launch crp 129 just waiting for the Mercedes connector to come, will that clear the fault or is there any other solution. Feel like getting ripped off at Mercedes.
        Thanks
        Mohit

  10. Hi Steve my 2002 C240 mercs SRS light and message saying visit workshop has come on
    Can you advise me to possible cause and rectification

    Regards Mik

    1. Hi Mik,
      Without connecting to a diagnostic reader capable of accessing the SRS system I would be just guessing at the cause of the problem. I am unsure if your model year had micro-switches in the front belt buckles, sometimes the buckle clasps need a good clean out and a spray with contact cleaner or WD40. There are a number of common failures that relate to that problem but identifying which is the true cause would be difficult without the tell-all code read.

      Make sure all the under-seat wiring is in place, often items pushed under the seat can disconnect the cabling under there. It could be the occupancy seat pad is broken (similar to the W210 write-up) or there is an issue with the ‘clock spring’ coiled flexible electrical connection to the steering wheel/air bag unit. The sad thing is that often once triggered the SRS lamp can only be reset with a capable code reader, only issues with belt clasps and seat pads will extinguish the lamp on correction of the fault. Most other issues even when rectified will need to reset to remove the red lamp from the instrument cluster.

      Probably the best advice is to do the simple things and visual inspection, if it does not fix it then get the system read at a good general garage or Mercedes independent repair shop – then at least you will know the true nature of the fault.

      Hope this helps
      Best regards
      Steve

  11. I drive a Mercedes A170 W169 2005. My clock spring broke inside my steering wheel. SRS and ESP lights on and car in LIM mode. How can I bypass this problem to get car out of LIM mode till I get the parts.

    1. Hi there Mario,

      To my knowledge there is no way to override the safety systems, sorry.

      Just to be clear, the above applies to activation of engine protection or ‘LIMP’ mode – You made reference to ‘LIM’ mode, as you probably already know: you can exit LIM mode by pushing in the end of the cruise control stalk.

      All the best
      Steve

  12. Hi Steve,

    I have changed the double passenger seat in my 2014 sprinter to a single. This has left the middle seat seatbelt tensioner missing from the airbag system. Any idea what size resistor i would be needing to complete the circuit. I would rather not have to hack the double seat up to take out the pretensioner…

    Any advice would be much appreciated, I have been having a nightmare trying to find the resistor rating required on the internet.

    Cheers
    Jake

    1. Hi Jake
      3.3 ohms is most common to airbag and SRS systems. This would be my choice for the pre-tensioner. See here. http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=261532870020&category=179486&pm=1&ds=0&t=1446894064557 or you could buy this very expensive ‘resistor in a box’
      http://www.ebay.co.uk/itm/MERCEDES-SPRINTER-CRAFTER-CENTRE-SEAT-REMOVAL-MODULE-SRS-LIGHT-ELIMINATOR-/331702184073?hash=item4d3afda889:g:mzwAAOSwsB9WAl-7
      All the best
      Steve

      1. Hi Steve,

        Thank you for your quick response. I think I will go for the first option! I will let you know how I get on.

        Thanks again
        Jake

  13. Hi Steve, I just purchased a 1999 Mercedes 180c.
    It had sat for a while with a dead battery.
    When i got the battery recharged and got the thing running, the SRS light went on.
    Took it to the workshop and the reeding were passenger airbag fault.
    I studied your text and bought a box from China on ebay.
    After conecting the wires, the light is still on.
    The OBD reeding is a big round thing in the left of the engine compartment.
    I cant find this tool on ebay or even when i google.
    Do you know where i could get this divice ?

    1. Hi John,
      You will need the PC software, interface and lead set from Carsoft, this works well with the older 38 pin connection to the electronics. Before you spend any more money it still may be worth checking seatbelt buckle switches as these are known to give similar problems. Used soft brush and table knife to clean the interior of the buckle. Use an electrical contact spray inside them to finish the job. If the seatbelt buckle fault is cleared the SRS lamp should extinguish without a dealer tool reset.
      Regards
      Steve

      1. Thank you for the quick respons.
        I ordered a cheap OBD scanner and it did not help at all.
        So i removed the seatbuckle but only to find out that there are not any wires coming out of it.
        The ABSoff-light in the console is also on.
        Can it be something else due to this light in addition?

        Thanks again
        John

      2. Hi John,
        It does sound like the seat pad or something related. I would check under the seat again to make sure that any wires that are connected to the explosive belt retractors are secure and pushed firmly home as well as double checking the compatibility and wiring on the seat pad emulator you have purchased.
        All the best
        Steve

  14. Hi there i hope you are very will ? I have big problim with my mb w211 let me i will start how come this tired!!! When i will draive the car on 1 second the car look like dead then am stop Near the street then car cut self i mean car stop work and switch off for self then am check for the main bettry on the back its dead after that i replace zinral get way cuse old one explode i don t know how but this my luck sir? After that i reaprogrammer car again cuse every thing after new betrry its worked sbc…gearbox,,,fan,,,srs… And many thing after programmer every thing work fine but i have something wrong related 1 draiver seats 2 draiver wheel and fog lamp not working pls brather i dont have many money spend for the car how i can fix this problim? ? I hope you are understand my english but i need some one help. Best regards

    1. Hi Ahmad,
      It sounds like there is still an issue with the central gateway clone. Was it programmed from the VIN or from the old blown unit? I would first be sure this is correct flash for the VIN as options seem to be missing from the CGW.
      Hope this helps
      Steve

      1. Hey brather again thanx very much for answer, about sentral getway am get new according vin then i will give the code number might am wrong when i bayed cuse the dealar he said i have other code simillar my get way the number of old one its (W211 540 56 45) then new one its (A169 540 69 45) am tired really cuse i have the car without benafit so let me i tallk with you about the things not working after the dammege 1 draiver seats not moving for all way but miror still work. /2 sound alarm securty gone but i can open the car remote but without sound alarm then if you know red press in key (panic) not working also and the gearbox somtime work fine sometime not/ 3/frog lamp 4/ i have something wrong also for speed control sometime i see light control work for self and go / today am start check fuise box diagram in the corner left its work 100% and about the fuise on the logauge am check also its work fine? And i replace the second bettry i mean small one on the front right but without binifit but i need give you thing am forget told you the main problem start when a/c pipe its get ice and his leak water on the electrical box now am check by pc i have many f f f f devises when i delet all f f f f and draive the car and check by pc again every thing gone cuse that i need someone thinking with me BEST REGARDS

      2. Hi Ahmad,
        Things seem to be a little wild. It seems to point to maybe a CAN communication issue if the gateway is working properly. From a little reading the central point for all can bus communication lies “in the wire guttering along the front door opening , there may be a broke wire of a corroded connector” Read this it sounds similar .http://www.mbclub.co.uk/forums/electronics/190490-can-bus-problems-i-think.html there is a chance the CAN is getting bad signals comms to/from the connected SAM units and causing a variety of issues. There is a chance water or damp could have got in here. Make sure all the twisted CAN wiring is connected well at the distribution point with no corrosion or poor connections. Worth a look.
        All the best
        Steve

  15. Hi Steve… I got a 1997 W202 (C230) and all the cluster gauges work sometimes, and sometimes these do not at all. I tried removing the cluster and reinstalling it again and get the same resullts; that is, sometimes these gauges work and sometime these don’t. Any suggestions?

    P.S… I should add that the cluster’s speedometer needle on this 1997 C230 makes a buzzing noise and flickers for about 5 seconds when ignition is turned on (key on second position), and/or when engine is turned off. Thank you!

    1. Hi Carlos,
      This fault often results in a dead dash, sometimes the temperature gauge continues to work correctly or sometimes the complete dash flashes on and off rapidly illuminating all of the status lamps at once.
      Quite a few mercedes clusters dating from around this time suffer from an issue with either electrolytic capacitors that dry out with age or faulty ( often due to the capacitors) blown voltage regulators. If you are familiar with electronics, then remove the cluster and take off the back. The capacitors and regulators will be visible on the pcb. You can get replacement parts off the web if you don’t have a Radio Shack type shop nearby. Other options are to replace the cluster or have someone repair it for you. I hope this helps.
      More reading on the subject here and a couple of suggestions where to get it repaired.

      http://www.benzworld.org/forums/general-mercedes-benz/1255719-pls-help-instrument-cluster-issues-w202-2.html

      All the best
      Steve

    1. Hi Bob,

      You are correct, the W208 in every case is very similar. You would be best to get an emulator that is stated to work with your vehicle if you needed one as there are a few types – but in general the same applies.

      All the best
      Steve

  16. Hi Steve,
    I have mercedes CLK430 year 2000. The problem i have is SRS light came on when I changed the driver seat belt, I purchase this seat belt in junk yard. I bring my car to the regular mercedes shop (not the dealer shop) and they can’t reset the SRS, the two shop say you have to bring it to the dealer. what Im afraid is the dealer will say replace the seat belt. But the driver seat belt cost $400 for the new one. also i call the junk yard to check were did they get the seat belt from the accident or the stationary accident they say from the stationary accident. Is there any way i can reset the SRS light, what should i do.
    Best regards,
    Ed

    1. Hi Ed,
      First I would be looking to see if the part numbers were the same as the unit removed. If they are the same, check out if there is a clasp switch in the buckle receiver. If so make sure this is working correctly. It seems strange how the independent MB dealer could not give you a fault code. Often dirt gets into the buckle and prevents the switch working. It may be worth checking the passenger side too. Ensure all the cabling is connected from the explosive device on the retractor and correct mating of all under seat wiring.

      Hope this is one help
      Steve

  17. Hi Steve,
    Thank you for a great website your very helpful article. I have the same problem (intermittent passenger seat occupancy pad failure related SRS warnings coming on) on my 2003, W203 C Class 200K. It is old pre- any facelift, and you wrote that in these models the problem can be solved if the seat pad is “linked out”. Does this mean simply disconnecting the seat pad connector plug? I think I have 3 plugs, 2 yellow and one brown, feeding the seat occupancy pad, the seat belt catch and the electric seat adjustment mechanisms, respectively. Your help will be much appreciated.

    1. Hi Noor,
      That model is new enough to require an emulator, you would need something like this one or a device specific for your vehicle and year. It simply plugs into the directed socket under the seat – Job done !
      Hope this helps.
      All the best
      steve

      1. Thank you very much for a lightning fast response – Wow! I’ll order the emulator and post on how it worked. Thankfully I got it through its MOT a couple of days ago extinguishing the SRS light (which is a failure reason now) by sitting in the passenger seat and jiggling my (ample) bottom! However I shall strongly defend any allegation that this action caused the broken driver side front coil spring, detected at the MOT, and judging by the mechanics’ swearing and cussing in taking the old one down, the £135 cost was money well spent rather than attempting the job myself!
        Best wishes,
        Noor

      2. No problem Noor,
        I hope it works out for you, just make sure you connect it exactly as it shows in their instructions and if you are unsure then give them a call – seems they have some form of help line that is always a bonus! Very funny reply and made me smile. Thanks for that.
        All the best
        Steve

  18. I put the emulator in today and worked a treat! Thank you for your help in saving me £££’s in a passenger seat sensor replacement. The coil spring replacement job was not so good unfortunately; there appeared a persistent clunk in turning to the same side (right, o/s/f), immediately afterwards. Took it back yesterday to have all the lower bolts re-torqued to no avail. Taking it back Monday again to have the shock/strut assembly taken down, and refitted, and also bought a new drop link to go with it. I wonder if there is a washer/bushing on the top of the strut where it attaches to the body (under the bonnet) which they might have forgotten to put back?

    1. Hi Noor,
      Glad the seat pad fix worked. The strut has a bearing on the top of the spring/strut. Its like two halves with a radial plastic channel (about five inches diameter) with about thirty ball bearings ‘loose’ that just sit in the groove and give freedom of rotation to the strut when steering. I have known when the spring collapses for a good number of these ball bearings to drop out and never be seen again. Whilst it acceptable to put it all back together with four or five missing, any more could cause a problem as the top of the turret would tilt over and rub in the places where the bearings used to support it/hold it apart. Its a long shot, but it could be this – as the spring rotation would stutter on a turn and make a sort of clunk (or in some cases a low boing) sound when turning the steering even stationary. The top of the strut is fairly simple and not many parts so I am assuming that it will be back together in the correct order.
      You can watch a spring being removed/fitted in this W203 strut video, the bearing I refer to is here and timed at 3:43 in the video

      Hope you get it sorted.
      All the best
      Steve

  19. Thanks for your very helpful comment and the video Steve. I took a close look myself over the weekend, and in shaking different parts it seemed to be a loose anti-roll bar drop link (the upper end). The garage had rounded off the 7mm bolt end during the first strut removal, so it was hard to tighten or take off, but I managed to replace it with a new one, and the noise seems to have gone. I cannot trust them enough (in not even diagnosing the noise source) so didn’t take it back as I didn’t want them to mess with taking off the strut again and damaging something else. Taking the strut off and messing with coil springs is beyond my own capability, tools and risk profile, so for now I’ll just wait and watch. Sound reasonable?
    Best wishes
    Noor

    1. Hi Noor,
      Makes good sense to me, we’re you fortunate to get a drop link with the hexagon end that can be held while tightening the 17mm nut, without this feature often not found on aftermarket parts can be a pain.

      All the best
      Steve

  20. Hi Steve,
    Thanks for all the nice write-ups. I came to own an 07 R320 CDI which
    has all sorts of electrical issues. The latest being the SRS light flashing
    all the time. I have tried using a Chinese knock-off DS3 system. The
    airbag controller passes self test. Do you have any experience in this area
    or do you know where I can get assistance? I have already taken the car
    to MB dealer who could not locate source of problem!
    Thanks,
    Ray K.

    1. Hi Ray,
      It sounds as if the Srs module has become unlocked to the system. It’s a complex fix described in detail here

      http://www.benzworld.org/forums/w211-e-class/1605898-srs-light-flashing-but-no-fault.html

      If you take this to a dealer they will fit and encode a new module. If you have access to developer mode on xentry then you may be able to configure it and save the day. Read that post a couple of times and give it a go. Not much to lose.

      Hope this helps
      Steve

  21. Dear Steve,
    I am in Brazil and I have a 2009 B200 turbo (W245). Today I went out to shop and when I returned to the car, it just does not start. No signal of any ignition. In the dash may read “SRS failure, search a authorized service”. I turned off the battery in an attempt to clean the system. Of course it not solved and I understood that the problem was more serious. A friend of mine informed me that the car does not start for safety reasons since the malfunction of the airbag can bring danger to the occupant. At this time the car is in the parking area of a supermarket and will spend the night there.
    Is there anything that can be done before calling a tow truck service and take the car for a Mercedes dealer?

    1. Hi there,

      I would imagine there has been an electrical fuse that has blown, probably one of the larger ones that protect several essential power circuits. This will probably result in power being lost to the SRS controller along with other fundamental modules required to start and run the vehicle. An SRS fault would not normally disable the vehicle to this extent and I am pretty sure the SRS issue is a result of the main fault and not the cause. My guess is a fuse link in the main power distribution SAM or other related main circuitry.

      Hope you get sorted.
      All the best
      Steve

  22. You obviously know more about airbags than me have the srs light on and the yellow one on centre console my mate put his snapon tester on it it came up with passenger side side air bag fault any tips I do have at my disposal a doner 320 mines a w208 320 cabriolet thanks darren

    1. Hi Darren,
      This sounds like a seat pad problem or seat belt clasp switch (microswitch inside the buckle part if fitted) You should be able to overcome the seat pad fault with an emulator as this post describes. The SnapOn tool is not reading in enough detail (generic fault code reading only) as if the fault was ‘Air Bag’ related it would normally illuminate the dash amber Airbag lamp as well as SRS. As this is not the case and just the SRS lamp and small console tell-tale airbag indicator is lit, it looks with pretty high possibility to be seat pad related.
      Hope this helps
      Regards Steve

  23. hello,
    I have a 1997 Mercedes SLK 230 compressor, which just failed the m o t on
    the SRS light staying on, The air bag light by the gear stick lights up,
    air bag off, the SRS light goes off, Then comes back on and stays on,
    I took the car to a local garage, He ran a test on the system but was unable
    to reactivate the air bag He removed a lot off faults from the ECU. we are now left
    with ID3 low volts,voltage supply circuit 15r, ID34, digital crash output wiring faulty
    ID27 front passenger seat occupied,child seat recongnition circuit, ID1 SRS control unit
    ID4 drivers airbag squib circuit, ID ,front passenger side air bag squib circuit,

    1. Hi Mike,
      Some complex codes there, a little misleading I would think. Discounting a faulty control module (which it may end up being) most of the faults relate to the passenger occupancy sensor circuit. I would be tempted to pull the seat and take a look at the wiring and cable connection in the loom. If the Air Bag lamp remains off and only the SRS lamp illuminates – chances are you are dealing with a localised seat pad or pad wiring circuit fault, in which case if its the internal seat pad/child seat occupancy detector a black-box emulator would fix this. I think my first attempt at this would be to fit an occupancy emulator to the passenger seat, its a cheap fix and would be the thing to do before going deeper into other components or modules. I would add that if the Drivers airbag circuit was faulty, then most likley the Airbag lamp would permanently accompany the SRS indication/illumination – so first signs are good!
      See how you get on by eliminating a possible seat pad fault before spending more time/money on this.

      Sorry for the late reply the message somehow found its way into the site spam box – now rectified!
      All the best
      Steve

  24. Good day to you. I had a customer’s car come in for a front bumper repair which entailed the removal and refitment of the bumper. The car is a 2012 MERCEDES WDD 204 SERIES C200. The repairs were completed and the car delivered. A day later the customer complained that the left front seat belt would not click/ fit into the stalk and the buzzer on the dashboard continuously on.I referred the owner to the MB dealer as the car was still under warranty.The service advisor stated that the stalk was faulty and it was replaced, but, t he seat belt warning light remains on.The second time around the service advisor says that the wiring underneath the seatwas damaged due to movement of the the seat over something that was placed underneath the seat. This is highly improbable as the owners are an elderly couple and do not need to put anything under the seat as they have the rest of the car to put things.The dealership has quoted ZAR2900.00 to fit a new wire harness and ledge which I feel should have been covered by the warranty as the car is in pristine condition,with a full service history and only 89000 kms on it. Please advise if the seat belt stalk,wiring and ledge don’t need replacement as a complete unit rather than individual parts.

    1. Hi there Raj,
      Well from reading that I would sadly deduce that the seat belt stalk probably genuinely went faulty. The dealer tech would have had to remove the seat to fit this. The seat was reinstalled and seatbelt tested. If the wiring problem existed at that point he would have at least reported it as it would be a safety issue regarding SRS. What may have then happened, totally innocently is, as the tech readjusted the seat to a forward/more normal position after completing and testing his work, the wires were likley damaged catching on the seat rails/runners as they were not suitably reattached/retained to their bracket under the seat base.

      Sadly all this would be difficult to make a case of at the dealer for obvious reasons, but how you describe the owners, it seems probable this is what may have actually happened. I would explain this to the service manager politley and calmly, putting a valid case over and see how he reacts. He should realise this is an entirely possible scenario and hopefully come to some ‘good will’ arrangement.

      Wire repair/ auto electrical work can be complex, but this is a seat and not an ecu! It should be possible to competently repair a few cut wires in a couple of hours at the most. That is not fairly reflected in their claimed invoice value if I have calculated the exchange rate correctly.

      Good luck, do let me know how you get on. I hope that helps you out a little. Its a difficult situation.

      All the best
      Steve

  25. Hi Steve (On the Ball)
    You really seem to have all the solutions, perhaps you can help me. I live in South Africa and have a 2006 C180K. The SRS warning light and error message come on with the ignition switch and the light remains lit with no flashing. This does not happen with a passenger on the seat and if I fiddle with the wire near the seat belt clip it sometimes goes off, so I guess the seat pad is probably OK. Is there a way of opening the seat belt clip to access the microswitch without damaging the black plastic cover or affecting the airbag system?
    Any advice in this regard would be greatly appreciated.
    Best regards
    Barry

    1. Hi Barry,
      Seems it could be some poor connection to the belt clasp or the internal microswitch. The clasp is glued together, the switch is inside so that pretty much scuppers any dismantling and cleaning. However if you use a round nose butter knife from the cutlery draw and carefully scrape around down inside the clasp its amazing what you can shift. Suck it up with a strong vacuum cleaner. Once you have cleared a lifetime of crumbs, grit and debris, give it a good dose of switch cleaner, operating the clasp with the buckle between times. More often than not if the issue is with the internal switch its with debris preventing it operating correctly more so than a contact fault within the microswitch.
      Be sure to check the seat pad connection into the plug under the seat and also inspect what you can see of the wiring up to the point it enters the seat base.
      Hope this helps
      All the best
      Steve (hopefully on the Ball!)

      1. Many thanks will give it a go in the next few days. Not a show stopper at the moment as the light goes off with a passenger seated.
        Refreshing to see a professional at work with realistic suggestions and resolutions and quick turn around.
        Thanks again, will let you know if the fix works
        Barry

  26. Steve, just to say thanks for sharing your knowledge. By just reading the through the posts has helped me and I’m sure a lot of others.
    Just your thoughts Steve. 2001 – cl500 – UK spec. can I add an Aux input to the (ipod -bluetooth etc) comand sys? the one with the cd gps tape and cd changer . I have heard that an aftermarket TV emulator will give an extra input also I’m considering a blue tooth FM sender from the cigar lighter- which way to go ?.
    I will change my Abc oil and filter in the next few weeks because a month ago I glued a strong magnet on the out side of the oil reservoir and it’s held some crud against the wall inside.
    Is there any additive like power steering refresh I can put in before changing the green stuff and maybe use a 3 micron inline fuel filter on the return line as a pre filter filter made of metal would be easy to use the magnets.
    Thanks in Anticipation.
    Frank.

    1. Hi Frank,
      Speak to chris Royal at Nav TV, email chris@nav.tv about the aux input, he may have some clues. I am pretty sure that there is a box you can get that interfaces between the six disc and the head unit enabling an alternative input. There are some pretty good audio senders that transmit an aux signal that you can tune to on the FM radio, but that is of course a work round – in some cases quite a good one!

      I would steer away from additives of any kind in this picky ABC system. Best thing to do is to try and replace as much fluid as possible in the system, this is a pretty good post to read – Not your exact model but the principals are exactly the same.

      Hope that helps,
      All the best
      Steve

  27. Hi Steve,

    I have a W211 E350 4matic 2006 and have been getting the “ESP display malfunction” and “ABS display malfunction” intermittently while driving which causes the engine to shut off completely. I’ll wait for a few minutes then restart the engine and everything works again, but after some time of driving, sometimes 10 min sometimes 2 hours, it happens again. The mechanic has changed several parts including the mass airflow sensor, both the main and auxiliary batteries, but to no avail.

    Any advice an experienced mechanic like yourself could provide would be greatly appreciated!

    Best Regards,
    Brian

    1. Hi Brian,
      I have a feeling there is a speed signal loss from somewhere. The fact this cuts the engine suggests it possibly has origins from a fault condition signalled from the transmission control module, as a protection measure.
      The ESP and ABS all use wheel speed sensors, there are also a number of speed sensors within the gearbox that add to the mix. If any signal is lost or interrupted and the transmission controller is unable to make sense of what the gearbox is doing then it will cut the drive (engine)to protect itself or engine from damage. I would imagine the 4matic has further speed sensor complexities.
      There is a conductor plate within the auto gearbox that is known to be troublesome, this controls the gear changes and internal speed signals. This plate can be changed by removing the trans pan without major gearbox work.

      There is reported issues with the seal on the electrical connector plug on the gearbox allowing gearbox oil to migrate through the loom to the gearbox ecu, causing electrical issues. Worth a look.

      You really need to invest in a dealer level diagnostic session on STAR. This should give you some vital clues as throwing parts and labour at the job without this is really financial suicide!

      One last thing that I seem to remember caused an issue on a W210 that was similar and took months of pain for all involved to finally bottom it was the throttle body, including the butterfly actuator (complete assembly) ESP and BAS lamps lit nothing else, engine died. The only fault code was ‘throttle pedal control unit’ that it obviously wasnt. Worth a go if you can find a used part cheaply enough.

      Hope this helps a little,
      Do let me know how you get on.
      All the best
      Steve

      1. Steve,

        Thanks for the suggestions and so quickly as well! Just wanted to add that the symptom also appeared after the engine idled for a while in Park, though also intermittently.

        The mechanic does have some kind of high tech scanner which pulled up a bunch of codes which was why he tried replacing some parts, but it seems the problem hasn’t been resolved and he’s at his wits end. Will keep you posted on how this turns out. Thanks again for the professional suggestions!

      2. Hi Steve,

        So the mechanic drove it for a few more times to make the symptom appear, and the error codes for the crankshaft sensor and camshaft sensor came up. He believes it’s the hot weather that causes the piezoelectric parts in those sensors to malfunction. I guess a black car sitting in 35 deg C weather absorbs a lot more heat than it should. So far so good, the warning lights haven’t come on in my short drive to work, and I’m keeping my fingers crossed. Your thoughts?

  28. my customer bring to my mercedes c170 the light SRS came in .i connecting my Maxidiag Elite founding the SRS problems.i earas it.tre times it not take it off.

  29. Hi do hope you can please help
    have a w202 c240 and the srs is permantly on and when driving the dash lights and instuments flash off and back on every now ad then
    if you bang the lower dash cowl you can somtimes simulate it
    it appers there may be a fault in the EIS have you has this fault before ?
    do you know if may be a dry joint etc or a complete EIS replacement is required
    thanks so much

    1. Hi Brit,
      I would pull the instrument cluster and check the multiplug wiring to the binnacle, any disconnection here would cause SRS illumination and once triggered would need a reset to cancel. It could be an intermittent connection here. Please review this article for reference to the plug and how it is removed/refitted.
      I am unsure how you think the EIS is problematic, perhaps this is a code you have read with a diagnostic reader. I would want to 100 percent sure any fault was attributed to the EIS/EZS module as it is a costly thing to replace as it has to be coded to the ECU, mileage matching/correction etc – a nightmare job! My own view would be to look elsewhere as often EIS codes are thrown when there is a battery voltage problem and again will not be cleared down unless cancelled from a compatible code reader. The SRS Airbag system should be read and subject to a good system diagnosis before turning to the EIS/EZS module.

      Hope that helps.
      regards Steve

      1. Hi fault codes say both impact side sensors are faulty find it hard beleive that both could go faulty at the same time ??
        If cleraed it takes 3-4 days to bring the light back on
        is there somthing common to both sensors apart from a control unit as this was replaced
        thanks

  30. Steve, you seem quite knowledgable on the topic of seatbelt wiring. I wonder if you might provide some insight. I am trying to disable my seatbelt warning – not for safety as I always wear my belt, but I do not often put my belt on before pressing my starter button. This sequence triggers a very annoying bell while I reach for my belt.
    Anyway, I pulled the two seat belt wires (drivers side) from the yellow harness and connected them together. This removed the seat belt warning bell, but threw an SRS warning. Is there supposed to be some resistance between the wires when the seatbelt is connected?
    I plan to go to the dealership to get the SRS reset (as I have done once before when I attempted this fix – this time I disconnected the battery before shorting the two wires, but this still resulted in the SRS warning), but need to know if I have to put the two wires back in the harness before they reset.
    Hoping you can help shed some light. Thanks!!

    1. Hi Mateo,
      The SRS warning will only reset when there is a correct set of conditions (connected correctly) so if you refit the cables correctly the dealer should be able to reset the code/light. I doubt it can be disabled in STAR – however if you buy a seatbelt stalk from a breakers yard with belt clip, you could I suppose hook this into the circuit under the seat. Probably putting up with it is the safer option, if you think thats an annoying noise go and try it in a SMART!
      All the best
      Steve

  31. I am driving a Mercedes c180 classic 1997.The SRS Red Warning light came on the Dashboard. The Red light came on in the Temperature area next to the half way mark of the temperature. The Temperature stayed in the half mark area. Please assist me.Thanking you in advance

    1. Hi John, If the temperature is not high and everything is normal then you could have a cluster fault. Remove the instruments and check/reconnect the plug arrangement at the rear. You will probably need to reset the SRS warning once illuminated. The pods of that era had electrical regulator issues on the cluster and the fault may be connected, though uncertain.
      Worth at least a look.
      All the best
      Steve

  32. We are driving a 2016 Winnebago Itasca Navion motor home with a Mercedes Sprinter Chaise. About a month ago the SRS message came on the instrument panel along with the yellow airbag icon that stays on. We took it to a Mercedes dealer they said the seatbelt wire was installed improperly and the wire was cut when the drivers seat was pulled forward or backward. Mercedes would not cover under the warranty because they said it was a Winnebago issue and they wanted $525.00 to pull the seat and repair the wire. Is the motorhome safe to drive, will airbags still deploy, until the wire is repaired by Winnebago who is covering it under their warranty?

    1. Hi Lindy,

      This problem is not unheard of with the later model range of Sprinter and is often reported. If they are covering under warranty thats great!

      You should be able to repair the cables under the seat (soldering and insulating) yourself if competent with a soldering iron, once these are repaired you should be able to have the SRS and airbag warning lights reset. The SRS and Airbag lamps illuminate to indicate a problem exists, not that the system will not deploy in an accident, more of – they may not deploy as intended! Its an indication to get it attended to and the failsafe mode is always to deploy under request , in the assumption that some airbag deployment is better than none. Of course its down to the nature of the fault that will affect what gets deployed and what does not in event of an emergency – so you are best advised to get it dealt with asap.

      Regards
      Steve

      1. Thanks Steve. Since we had a trip planned in a few days, we also called the Mercedes factory and in so many words he said the same thing. We believe when the Mercedes mechanic was looking for the issue he took the other end of the wire with the little plug, so we are minus that anyway, unless it dropped down way under the seat. As it is we have an appointment with Winnebago, BUT couldn’t get in for a month:( Your advise at least told us we were not being lead on a wild goose chase.

        Thanks for the quick reply,
        Lindy

  33. Hi Steve ,
    W215 ,
    i had the fount lights , change to drive over in the EU, After havey rain i had two faults,
    one was the fount driving light when out , after i turn car off , and then on again this seem to have fixed it self , The other is the SRS showing fault , any advice ,

    regards Oliver

    1. Hi Oliver
      You need to check the lamps and connections if Xenon’s the ballast and waterproofing. Very high voltages are present and moisture is not friendly to this kind of lamp. The SRS could be as simple as a seat pad fault, you would have to have it diagnosed to be more accurate. Chances are the two problems are not related at all.
      Regards
      Steve

      1. Hi Steve
        And thank you, will get it checkout ,
        seem the lamp holder needed a little turn, Ther is a SRS secor there about , thinking maybe
        just a jolt in voltage , knock it out ,
        Regards
        Oliver

  34. Hi Steve, I have a 2005 Clk320 and the srs light appeared when my car battery had no juice in it. I replaced the battery but the srs light is still there. Can you tell me how to fix this? Thank you so much.

    1. Hi Hung,
      The SRS lamp on the C class of that year will have to be reset once triggered. It would probably have been battery voltage to the instrument console that dipped causing an indication similar to that of a disconnection of the pod with the ignition on. A diagnostic tool reset to the SRS system should get you back to normal.
      All the best
      Steve

    1. Hi James
      The seat pad on earlier models that did not have child safety seat detection option (pre-facelift and other older models) had more of just a ‘switch’ type contact pad in the seat base. This can usually be simply be linked out if it is broken under the seat and the occupant system bypassed.
      Best regards
      Steve

      1. Hi Steve,
        On a Mercedes e class 220, w211, I have trouble with SRS in the dash and also the message “‘ power restraint” What could I do to fix it. I have been to the shop and they put the tester on it and erase the erors and all its good untill I stop the engine and restart the engine. Than I have the erors again in the dash. Please let me know what I could do to solve the problem.

        Thanks and wish you a good day, Ionut

      2. Padurariu,
        There is a secondary battery on that model, you will need to make sure that it is functioning correctly as low charge or poor power supply can cause repeated faults. It seems your issue is most likely in thew self test procedure and could be connected to to low voltage on key on.
        Regards
        Steve

  35. steve just trying to finish this job, do i join the red and white wire under the seat to put the light off?

    Thanks james

  36. Hello Steve, hopefully you can give me a little help with my problem. I have a 2004 C320 and my SRS light is on. I have purchased a Scanner that is supposed to be able to read and clear the SRS codes. My problem is that when I connect the scanner and try to access the SRS Module, I get a no communication error. I have also borrowed another scanner from a friend and that Scanner gives me the same error. Could you give me a little direction from here?
    Thanks in advance.

    1. Shawn,
      Chances are the scanner will not communicate with the Mercedes SRS module. This is common in non model specific scanners, you will need something along the lines of at least an Autel or Star copy to reset/read those codes.
      All the best
      Steve

  37. Hiya Steve
    I have a mercedes benz c class w203 kompressor c200,my fuel gauge doesn’t seem to work, I have tried removing the sender units to check for any broken wires,none found. Oh gauge doesn’t even flick on the instrument cluster when you the ignition on. Any ideas mate?,. I know I might have to replace both sender units, but I thought I would ask for ideas first coz they don’t come cheap. Cheers.

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