Troubleshooting by Diagnostic Trouble Code (DTC) - DTC P0131/P0137

DESCRIPTION AND OPERATION

Refer to the corresponding procedure for DTC P0130 and P0136.

DTC SET CONDITIONS

[For DTC P0131] 3 minutes after the front heated oxygen sensor heater is turned on, the engine control module continuously measures the front oxygen sensor signal voltage at 0.5 second intervals. If the front oxygen sensor signal voltage falls below 50 mV for two driving cycles, the engine control module will store DTC P0131 and illuminate the malfunction indicator lamp (MIL). This code indicates an abnormally lean air-fuel mixture measured by the front oxygen sensor or the engine control module.

[For DTC P0137] When the multi-point fuel injection (MFI) system is under closed-loop air-fuel ratio control and the engine has operated in this mode for 3 minutes, the engine control module checks the rear oxygen sensor signal at 0.5 second intervals. If the rear oxygen sensor signal voltage falls below 50 mV for two driving cycles, the engine control module will store DTC P0137 and illuminate the malfunction indicator lamp (MIL). This code indicates an abnormally low signal voltage measured by the rear oxygen sensor or the engine control module.

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECTION PROCEDURE