DTC P0138: Notes

DTC P0138 [L3] CHART

DTC P0138	Rear HO2S circuit high input
DETECTION CONDITION	The PCM monitors input voltage from rear HO2S. If the input voltage from the rear HO2S sensor is above 1.2 V for 0.8 s , the PCM determines that circuit input is high. Diagnostic support note This is a continuous monitor (HO2S). MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA is available. DTC is stored in the PCM memory.
POSSIBLE CAUSE	Rear HO2S malfunction Short to power supply in wiring harness between rear HO2S terminal A and PCM terminal 2AH Rear HO2S or PCM terminal shorted PCM malfunction