Circuit Description

The Powertrain Control Module (PCM)/Engine Control Module (ECM) monitors Oxygen Sensor (O2S1) to determine time taken for O2S1 to become active after a cold start. The PCM/ECM supplies a reference voltage of about 4.5 volts to O2S1. During monitoring period, PCM/ECM measures elapsed time taken for O2S1 output voltage to vary by +0.126 volts from mean bias voltage (.45 volts). With this information PCM/ECM can determine if O2S1 is functioning properly and has become active within specified time limit. If too much time is needed for O2S1 output voltage to vary, DTC P1130 will be set.