Oxygen Sensor: Description and Operation

CIRCUIT OPERATION
There are four heated oxygen sensors used on this vehicle, regardless of engine application. They are identified at the left upstream, left downstream, right upstream, and right downstream.

Power for the heated oxygen sensors is supplied on circuit A142. This circuit is HOT when the contact side of the Automatic Shut Down (ASD) relay is CLOSED. The Powertrain Control Module (PCM) controls the ASD relay by providing a ground path on circuit K51. The K51 circuit connects to cavity 67 of the PCM connector.

Circuit K41 delivers the signal from the left upstream heated oxygen sensor to the PCM. Circuit K41 connects to cavity 30 of the PCM connector.

Circuit K141 delivers the signal from the right upstream heated oxygen sensor to the PCM. Circuit K141 connects to cavity 29 of the PCM connector.

Circuit K341 delivers the signal from the left downstream heated oxygen sensor to the PCM. Circuit K341 connects to cavity 51 of the PCM connector.

Circuit K241 delivers the signal from the right downstream heated oxygen sensor to the PCM. Circuit K241 connects to cavity 1 of the PCM connector.

The PCM provides a ground for the heated oxygen sensor signals (circuits K41, K141, K241, and K341) through circuit K4. Circuit K4 connects to cavity 43 of the PCM connector.