I was called to a friends Mercedes Sprinter 311 MWB that had an intermittent Limp Home problem. I took with me, along with my tools, the video camera and the Autel diagnostic code reader. Within only a few minutes had I diagnosed the fault and rectified the problem. In the short video below you will see how a quick read of the fault codes goes a long way to detecting and rectifying problems that occur intermittently.
In this case there were several fault codes flagged, the ones relating to ‘faulty glow plugs’ were ignored as the vehicle was known to have issues here before. Historically with Sprinters in the UK the fact the glow plugs do not function correctly does not cause a problem, indeed most vehicles I deal with do not run with them connected at all – as the risk of head damage during replacement is disproportionate to the trouble-free running without them! There was No EDC light showing at the time of restart, so stored codes were to tell us what we needed.
Once the ECU was read, there was a ‘cam and crank synchronisation’ fault logged – this is often bought up when there are starting issues, and this vehicle had been reported as having problems starting on two occasions, so these were ignored as red-herrings.
I decided the most obvious culprit in the list would be the ‘injector 2 disconnected’ fault. Once I had lifted the bonnet and inspected the connectors I found that several had broken retaining clips on the injector plug cable bodies. Obviously with vibration these were likely to give connection problems and sure enough No.2 was loose. I fitted nylon ty-wraps to retain all the connectors to the injector towers.
I cleared the faults using the Autel Maxi-Diag and road tested the vehicle. No faults have since been logged or reoccurred. This once more goes to prove that some times the faults logged and displayed on the code reader are often as a result of the problem and not always an indicator of the cause. In this case several codes were flagged because of one main issue – the ‘injector 2 disconnected’ Intermittent connection.
At almost a quarter of a million miles under its belt, apart from some leaking diesel on the fuel rail bleed off pipework this Sprinter is fit for a few more journeys yet!