Circuit Description

PCM provides about 0.45 volt (450 mV) reference to HO2S. HO2S sensor signal voltage varies from about one volt (1000 mV) when exhaust is rich to about 0.1 volt (10 mV) when exhaust is lean. PCM reads and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If HO2S voltage is out of predetermined range, DTC will set.

For duplication of DTC, ensure engine is running and no active fuel trim, fuel injector circuit, misfire, EVAP system, EGR pintle position, TP, IAT, MAP, ECT, CKP, or MAF sensor DTCs are set.