DTC P0131, P0151: Notes

DTC P0131, P0151 [AJ] DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0131 DTC P0151	HO2S (RF) circuit low input HO2S (LF) circuit low input
DETECTION CONDITION	The PCM monitors the front HO2S output voltage when the following conditions are met. If output voltage is less than 0.1 V for 41 s , the PCM determines that the front HO2S signal remains lean. MONITORING CONDITION Fuel injection control system status: feedback zone The PCM monitors the input voltage from the front HO2S when the following conditions are met. Under the following monitoring conditions, if the input voltage from the front HO2S does not even exceed 0.1 V though the short term fuel trim is controlled up to 25% for 9.6 s , the PCM determines that sensor circuit is not activated. MONITORING CONDITIONS HO2S, HO2S heater and TWC Repair Verification Drive Mode Following conditions are met Time from engine start is above 50 s (ECT when engine start is 20 °C {68 °F} ). Diagnostic support note This is a continuous monitor (HO2S). MIL illuminates if the PCM detects the above malfunctioning 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 conditions during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in the PCM memory.
POSSIBLE CAUSE	HO2S (RF) malfunction Short to ground in wiring between HO2S (RF) terminal A and PCM terminal 2AK Open circuit between HO2S (RF) terminal A and PCM terminal 2AK Open circuit between HO2S (RF) terminal B and PCM terminal 2AV HO2S (LR) malfunction Short to ground in wiring between HO2S (LF) terminal A and PCM terminal 2AL Open circuit between HO2S (LF) terminal A and PCM terminal 2AL Open circuit between HO2S (LF) terminal B and PCM terminal 2AX PCM malfunction

DTC P0131
DTC P0151

HO2S (RF) circuit low input
HO2S (LF) circuit low input

DETECTION CONDITION

The PCM monitors the front HO2S output voltage when the following conditions are met. If output voltage is less than 0.1 V for 41 s , the PCM determines that the front HO2S signal remains lean.
MONITORING CONDITION
- Fuel injection control system status: feedback zone
The PCM monitors the input voltage from the front HO2S when the following conditions are met. Under the following monitoring conditions, if the input voltage from the front HO2S does not even exceed 0.1 V though the short term fuel trim is controlled up to 25% for 9.6 s , the PCM determines that sensor circuit is not activated.
MONITORING CONDITIONS
- HO2S, HO2S heater and TWC Repair Verification Drive Mode
- Following conditions are met
  - Time from engine start is above 50 s (ECT when engine start is 20 °C {68 °F} ).

Diagnostic support note

This is a continuous monitor (HO2S).
MIL illuminates if the PCM detects the above malfunctioning 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 conditions during first drive cycle.
FREEZE FRAME DATA is available.
DTC is stored in the PCM memory.

POSSIBLE CAUSE

HO2S (RF) malfunction
Short to ground in wiring between HO2S (RF) terminal A and PCM terminal 2AK
Open circuit between HO2S (RF) terminal A and PCM terminal 2AK
Open circuit between HO2S (RF) terminal B and PCM terminal 2AV
HO2S (LR) malfunction
Short to ground in wiring between HO2S (LF) terminal A and PCM terminal 2AL
Open circuit between HO2S (LF) terminal A and PCM terminal 2AL
Open circuit between HO2S (LF) terminal B and PCM terminal 2AX
PCM malfunction