SES help?

[Tahoe933]

SES starting coming on a few days ago after the truck runs for a bit.

Ran the Autoxray on it yesterday, no trouble codes, so I set it to monitor data and went for a drive.

Light comes on after about 5 minutes of in town driving. Scanner says truck is still in open loop. Only other code that I see a problem with is O2 sensor, showing "not ready". The other O2 reading shows 440mv and is changing with conditions.

Sensor only has @5k miles on it.

Think it is shot already? Wires don't look damaged. Mike

[Import Hater]

Could have a bad heater. Is it an aftermarket sensor?

[Tahoe933]

It's a Bosch sensor. Usually d**n good stuff. I think you are right. It Lights the SES soon after start, but it goes out once you start running the engine at highway speed. Performance is fine. I'll be taking the sensor back to see if I can get anything on a replacement.