sraelatham

I have a 99 E320 4Matic.. The check engine light came on a few weeks ago and the code was for bad 02 sensors on the drivers side (both of them). We just had them replaced and the engine light went off for about a half an hour, then came back on with the same error code (bad sensors). Took it to Autozone and the gentlemen mentioned that it could take a while for the engine light to go off since the sensors were just replaced. Does this sound like an accurate statement, and if so, how long should I wait before I worry? I can't smog it till this issue is cleared up and the registration is now late since the issue started right before my smog was due.

Thanks!!!

RichardM98

Yes, it's true that a required number of 'drive cycles' are necessary for the electronics to reset itself. Usually 3 trips of 20 miles over two or three days will do it. If you don't wait, it won't pass smog anyway. The smog computer will get an status error.

Hirnbeiss

If your sensors failed due to mileage (somewhere over 100k), I would replace all 4 at the same time.

renault12ts

I agree with that.