[amidgeha]

O2 Sensor Signal Biased/Stuck Rich

The downstream heated oxygen sensor (HO2S) is forced rich and lean and monitored by the Powertrain Control Module (PCM). The test fails if the PCM does not detect the output of the HO2S in a calibrated amount of time.

Cause:
Faulty O2 Sensor Bank 1 Sensor 3
Exhaust leaks
O2 Sensor Bank 1 Sensor 3 harness is open or shorted
O2 Sensor Bank 1 Sensor 3 circuit poor electrical connection

Symptoms:
Check engine light