Oxygen Sensor
This sensor is mounted in the exhaust manifold. It supplies a low voltage when fuel mixture is lean (too much oxygen) and a higher voltage when fuel mixture is rich (not enough oxygen). Oxygen sensor must be hot to function properly. The oxygen sensor measures quantity of oxygen only.
NOTE:
No attempt should be made to measure oxygen sensor voltage output. Current drain of voltmeter could permanently damage sensor, shift sensor calibration range and/or render sensor unusable. DO NOT
connect jumper wire, test leads or other electrical connectors to sensor. Use these devices only on ECM side of harness after disconnecting from sensor.