I have read through most of the threads on the O2 sensor. But have not seen the answer to my question.

When I start my car either hot or cold, everything is normal. Then about 5 minutes after I started it, the Check Engine light comes on. Is this the O2 sensor? I do not sense any difference in idle or anything when the light comes on?

Reason I ask, is that I just talked to my MB Indy Shop and asked about this, and he said that they start with cleaning the O2 sensor with Injection Cleaner, and if that does not stop the light from coming on, they then work the injection system. It seems strange that he did not even mention changing the O2 Sensor.

Thanks in advance.

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Insanity: doing the same thing over and over again and expecting different results.

2006 - Suzuki Gran Vitara (2.0 L fully equipped) Like this car so far except for trying to put on the seatbelt.
1988 - 190e - 2.3L - 172K miles (It now belongs to the exwife)
1999 - Chevy Blazer LS Fully Equiped - killed it June 2006
2001 - Honda Civic EX - 68K miles (sold June 2004)
1963 - 220S - Dual Carb 6 cyl. (sold)
1994 - Yamaha WaveRaider (fun to ride)