Oxygen Sensor Readiness check
 

Hello,

I have a 1999 C280 that needs to pass smog in about a week. 2 weeks ago while trying to delete old codes from a check engine problem that I fixed I ended up also deleting the readiness checks that the car does.

There are 7 readiness checks total, and I have one remaining, the oxygen sensor. I found the drive cycle that you are supposed to perform to complete these readiness checks. I have done it several times, but still the oxygen sensor check comes up as incomplete when I scan the OBD2.

On a copy of the drive cycle I am supposed to do, it says that the O2 sensor response time and switching time is being monitored when I drive from 20-30 and 40-60. Does anyone have any further information on how I can complete this check? Any help is much appreciated.

Thank You.

How far have you driven? I had to drive about 60mi with 2-3 drive cycles to reestablish everything after clearing a code just before going in for a smog check.

Did you replace the O2 sensor? If so, could it be that the O2 sensor is incompatible with MB? Some have bought sensors on eBay which weren't.

Good luck.