'03 Tahoe trouble code

[izzy1776]

My wife's Tahoe's check engine light came on the other day. Scan tool gave us the code:

P0158 O2 Sensor circuit high voltage.

It says to do a bunch of voltage readings around the O2 sensor behind the cat. Wondering if any of you have had experience with this.

 

[skunked]

likely a bad O2 sensor.

no exhaust leaks and it's otherwise running OK right?

 

[izzy1776]

Haven't heard any leaks and the wife says it's feels like it always has. I think I'm gonna get a new sensor and see how it goes.

 

[4xcrazy]

My uncle has an '02 and wouldn't pass Cali emissions due to a bad cat, from what I understood, the rear O2 sensors were there to make sure the cats were working properly.

That's the way it worked on my dads car at least, when the cat blew out it kept lighting the CEL and was always that 2nd sensor behind the cat. Installed a new cat and everything worked fine again. Drove the same either way as well, but wouldn't pass emissions due to the lit check engine light.

 

[Babaganoosh]

My uncle has an '02 and wouldn't pass Cali emissions due to a bad cat, from what I understood, the rear O2 sensors were there to make sure the cats were working properly.

That's the way it worked on my dads car at least, when the cat blew out it kept lighting the CEL and was always that 2nd sensor behind the cat. Installed a new cat and everything worked fine again. Drove the same either way as well, but wouldn't pass emissions due to the lit check engine light.

That is correct, sounds like a bad cat the rear o2's are for metering.

 

[skunked]

not necessarily.

I had the same issue on my FIL 03 Tahoe, the O2 sensor had failed in his case.

Remember our CA compliant cats are $900 so a $50 O2 sensor is worth a shot, or at least swap the left and right bank sensors.

 

[Babaganoosh]

Correct, given the voltage readings will determine whether it is bad or not.

 

[izzy1776]

Swapped the Oout for a new one. Used the DTC to clear the code beforehand. Wife says it's running a bit peppier than before. Will wait to see if anything happens again. But for now the $50 O2 sensor is winning.

 

[skunked]

Swapped the Oout for a new one. Used the DTC to clear the code beforehand. Wife says it's running a bit peppier than before. Will wait to see if anything happens again. But for now the $50 O2 sensor is winning.

nice