Circuit Description

PCM provides about 0.45 volt reference to Heated Oxygen Sensor 1 (HO2S 1). Sensor signal voltage varies from about one volt when exhaust is rich to about 0.1 volt 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 1 voltage is out of predetermined range, DTC P0154 will set.

For duplication of DTC, ensure no misfire, fuel injector circuit, fuel trim, EVAP system, EGR, CKP, MAF, TP, IAT, MAP or ECT sensor DTCs are set, system voltage is greater than 9 volts, and engine has been running for at least 4 minutes.