Both 02 Sensors in Bank 1 bad???

[crepitus]

I have been getting a CEL for my O2 sensors in bank 1 both sensors. Could it be the Pre cat sensor is the bad one making the post cat sensor read wrong as well? Trying to save a few bucks if I dont have to replace both of them.

[asc08]

Can't answer you question, but you may want to check with the dealer, O2 sensors may be covered under the 'extended' emissions warranty. Check you warranty manual for the specific parts, many of them, I believe, are covered 8 yr/80 k miles.

[crepitus]

I called the dealer and of course they are not covered under the extended emmissions plan.

[brantjs]

Had this problem in my wife's van...it was in fact the pre-cat sensor that was bad and caused the other one to throw the code as well. I don't remember the specifics but if you pull the sensor you can do a quick resistance check with a multimeter. You should be able to do a search and find the acceptable values posted somewhere online, or ask in the gm tech section and see if someone can check in the service manual.

[uh6tdrvr]

If you have two that are out it is about the same price to get a custom tune and tune them out...and it will damn sure run better after that!