Oxygen Sensor: Description and Operation

When the Automatic Shut Down (ASD) relay contacts CLOSE, they connect circuits A16 and K125. Circuit K125 splices to supply voltage to the heated oxygen sensors.

Circuit K141 delivers the signal from the upstream heated oxygen sensor to the PCM. Circuit K141 connects to cavity A24 of the PCM. Circuit K341 deliver the signal from the downstream oxygen sensor and connects to cavity A25 of the PCM.

The PCM provides a ground for the heated oxygen sensor signals (circuits K141 and K341) through circuit K4. Circuit K4 connects to cavity A4 of the PCM connector.

Circuit Z11 provides a ground for the heater circuit in the sensors.