Normally, when the owner of a diesel complains of a starting problem, it is expected to be either low battery or fuel related. So I would expect the job to be either checking the charging rate or the glow plugs. The owner of this 2008 Mercedes C200 Elegance diesel had described the problem as being poor starting, but the fault was actually that there was no response when putting the key into the ignition.

Occasionally when putting the key into the ignition the engine would fail to turn, and also would not release the steering lock. When this occurred, the owner would repeatedly pull the key out of the ignition and then try again, until eventually the key would turn and the car would start.

This is a problem I have come across before on the C-Class, and it can be down to one of three different problems. Either the key or receptor has failed or the steering lock mechanism itself has failed. Knowing from experience it is best to get this problem resolved before total failure. If the problem is the steering lock mechanism, removing it when in the locked position is a very difficult task. This is because when locked the stud which holds it to the column cannot be released. The only way then is to start sawing.

Luckily, this one could be activated and then the securing nut could be removed and the stud pushed back to release the lock assembly. Once in place, the new unit then needs to be coded using Mercedes software, so not one to tackle without the proper kit.

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