Circuit Description

Powertrain Control Module (PCM) supplies about.45 volt (450 mV) to Heated Oxygen Sensor (HO2S). The HO2S generates a voltage that varies from about one volt (1000 mV) when exhaust is rich to about.10 volt (10 mv) when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S voltage remains at or near.45 volt (450 mv) for an extended period of time, DTC will set.

For duplication of DTC, ensure:

• DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358 and P1258 are not set.
• Ignition voltage is greater than 9 volts.
• AIR, EGR and catalyst diagnostics are not active.
• Fuel system is operating in closed-loop.
• Engine run time is greater than 70 seconds.