DTC P2271, P2273: Notes

DTC P2271, P2273 (MZI-3.5) DETECTION CONDITION AND POSSIBLE CAUSES

DTC P2271	P2271: Rear HO2S (RH) signal stuck rich
DTC P2273	P2273: Rear HO2S (LH) signal stuck rich
DETECTION CONDITION	The downstream HO2S is forced rich and monitored by the PCM. The test fails if the PCM does not detect the output of the HO2S in a calibrated amount of time.
POSSIBLE CAUSE	Rear HO2S malfunction