Code Enable Criteria
- Engine run time is greater than one minute.
- No CMP, CKP, ECT, EGR, EVAP purge solenoid, fuel trim, IAT, MAP, misfire, system voltage, or TP sensor DTCs are set.
DTC sets when O2S1 voltage is inactive (not reading outside 391-491 millivolts) for greater than 90 seconds.