Symptoms

Misfire and engine stalling while driving. It is not possible to restart the engine or it takes some time to start. Occasionally the engine will not start. No faults are stored in the fault memory.

Cause – defective voltage supply relay contacts

If you can rule out, that the cause of the faults described is the immobilizer (then the engine goes out after approx. 2 s), the most common is a faulty controller power relay. The fault may only be sporadic or depending on the temperature. This is due to cracks or "cold" solders on the relay's PCB.

Troubleshooting and fault elimination

If the faults persist, the conductivity of the circuit board should be measured. If this is not possible, test the relay, because the defects on the PCB are very difficult to see.