DTC P0131: Notes

DTC P0131 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0131	Front HO2S 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 49.8 s (ECT when engine start is 20 °C {68 °F}). Diagnostic support note This is an intermittent 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. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Front HO2S malfunction Connector or terminal malfunction Open circuit in wiring harness between front HO2S terminal A and PCM terminal 2AG Short to body ground in wiring harness between front HO2S terminal A and PCM terminal 2AG Open circuit in wiring harness between front HO2S terminal B and PCM terminal 2AA PCM malfunction