I've owned my 03-plate Mercedes-Benz SLK 200 Kompressor for five years. It was supplied by a Mercedes-Benz dealer but I have chosen to have it serviced by a non-franchised company with Mercedes-Benz experience. The car is in good shape and has done 53,000 miles. Now, the engine management light keeps coming on and reports indicate that the fuel injection system is the source of the problem. It is more likely, however, that it is a bigger issue concerning oil in the wiring loom that links the EMU with numerous sensors. The car runs well enough at the moment but, of course, has an unpredictable warning light. This obviously makes it a tricky selling prospect.

I'm undecided about starting the process of repairing/replacing/renewing expensive electronics and wiring, but I could afford to do this. Up to this point, it’s been the best car I’ve ever owned and suits my lifestyle well. Obviously any discussion with Mercedes-Benz about trade-in would quickly uncover the problem, although I would admit it from the outset. Full repair surely can’t be as much as I’d need to spend on a replacement car of any make. Is an 03 SLK worth such a major investment?