I am new to this forum after doing a TON of reading on the wiring harness problems on the 93-95 mercedes here...thanks for all the great info. I have a 95 c220 which has finally succumbed to this symptom at 97K mi when the check engine light came on.

I first took it to the dealer where they said to replace the engine and coil harness and the 02 sensor. I thought it was odd they could diagonse the 02 sensor when the wiring harness was crumbling. Anyway, their price was absurd and didn't do much wih the goodwill warranty so I took it to an independent Merc mechanic and they verified the harness needed replacement and also extrated other sensor codes which they said probably is a result of the bad harness.

The car is still in the shop but they replaced the harnesses and all seems well so far. They have been driving it and the check engine light doesn't come on.

My question is: Should I replace the O2 sensor even though the check engine light doesn't come on anymore? From what I have read here, the 02 sensors tend to need replacing around 100k miles anyway. Or should I just hold off until the light come on and the codes says to do it then? What harm am I doing by not changing it now?

Thanks!