Software Problems of Mercedes Benz C230

Mar 'interior dash light warning "check engine" came on. I immediately brought it to a mercedes-authorized mechanic; computer diagnostic said "fuel trim error". Mar to oct '07 following parts were replaced: all fuel injectors, spark plugs, engine wiring, all engine gaskets & 2 maf (mass air flow) oxygen sensors; additionally, the compressor unit was taken apart 7 times, and upon examination, a very small amount of oil would be discovered - 1 tsp to 1 tbsp ea time. Each time, it was impeccably cleaned. Total cost to owner over 7 months: $3,500. During car ownership, the car has been maintained according to mercedes repair schedules, using only oem parts and products - it only has 86k original miles on it - very low for an 8 yr old car. The mechanic observed that the blow back oil accumulates in the compressor, so the computer sensor thinks the engine is running too rich and will virtually shut down power to the compressor. The compressor itself was tested after each cleaning, and runs perfectly. It only when the interior compressor sensors picks up minor molecules of oil, that it thinks it is running too rich, and will not deliver power to the engine. This is especially dangerous, because it is not predictable, and when it occurs, the driven is unable to climb hills or even slight inclines, and can not exceed 65 mph without a >50% loss of power to the engine. The car can not even accelerate on a slight incline and will loose 10-20 mph as a result. It was assessed by the mechanic, after watching it for 6 mos and reinspecting 6 times (all with the same fuel trim error, and no other computer errors registering) that the blow back is from interior o rings, very deep in the engine: repair cost est: $3-5k. This type repair is not heard of on a mercedes with 86k miles, with the care taken. The car is undriveable due to the inordinate repair costs (TX dot inspection does not pass with "check engine" light problems).

See all problems of the 1999 Mercedes Benz C230 🔎.