DTC P0138:00: Ho2S Circuit High Input: Notes

DETECTION CONDITION AND POSSIBLE CAUSE

DTC P0138:00	HO2S circuit high input
DETECTION CONDITION	The PCM monitors input voltage from HO2S. If the input voltage from the HO2S is above 1.2 V  or HO2S bias voltage is above 1.8 V  for 5 s  , the PCM determines that the HO2S circuit input is high. Diagnostic support note  This is a continuous monitor (A/F sensor, HO2S). The check engine light 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 first drive cycle. FREEZE FRAME DATA (Mode 2)/Snapshot data is available. The DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION	-
POSSIBLE CAUSE	HO2S connector or terminals malfunction PCM connector or terminals malfunction Short to power supply in wiring harness between the following terminals: HO2S terminal A-PCM terminal 2AI HO2S terminal B-PCM terminal 2AG HO2S malfunction PCM malfunction

CAUTION:

• Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.

RELATED PIDS

Monitor item (Definition)	Unit/Condition	Condition/Specification (Reference)
VSS	KPH, MPH	Displays the vehicle speed
RPM	RPM	Displays the engine speed
O2S12	V	Idle (after warm up): 0-1.0 V  Deceleration fuel cut (accelerator pedal released from engine speed of 4,000 rpm or more): approx. 0 V