P0135 GMC - 2003 Safari

Question

showing P0135 code on 2003 Safari that has been getting poor gas mileage. CanOBD2 scan tool indicated that Test ID $0E was high with a value of $0009 vs max value of $0008. Mod ID $10 and component ID $11. Does this indicate that the O2 sensor needs to be replaced and where is it located on the 2003 Safari 4.3 V6?

Answer 1

P0135- 02 sensor heater circuit malfunction bank 1 sensor 1

The test ID max out, so yes and also the "P" powertrain code says it all, Bank 1 is where cylinder 1 is and sensor 1 , is the first 02 sensor, the sensor on the catalytic or afterthe catalytic is sensor 2 which are catalytic monitor,

Comments

Followed the information that Reynaldo gave me and found O2 sensor in question to original problem was black at the base. The other two sensors looked normal with tan oxidation, but replaced all three O2 sensors since the vehicle has 95000 miles and the sensors were not that expensive. Reset the codes drove about 10 miles and now I am still getting a yellow caution code on emissions. No code is setting after driving another 20 miles. What I am seeing on the recorded live read out is a constant reading of 99 on the short term fuel trim (B1-S2) vs -7 to +7 on STFT on (B2S1) and (B1S1). What would cause this problem?