my check engine light came on again . this is the third time I now have a permanent cat code and a po 171 code the dealer keeps bs that the cat code will go away which it does for a couple of weeks but comes back the permanent code has never left . all the recalls the car has had some of which i had to tell them about because they knew nothing till i walked in with a printed copy. to prove they needed to be repaired at no charge. does GM give a fu--.

 

p0171 is a fuel trim lean dtc...not cat releated. look at the freeze frame data that is stored when the code sets. what is the rpm when the code sets?

 

since posting my car has posted a new code p2270 o2 sensor stuck bank 1 sensor 2, the p0171 is now permanent not pending. I will look at the freeze frame data. thanks for the advice. to me it looks like the o2 sensor died.

 

if the fuel trim is stuck lean...the 02 sensor won't switch. one effects the other. make sure the fuel trim is +/- 10% before you replace an 02 sensor.