Oxygen (O2) Sensor
- Warm engine to normal operating temperature. Disconnect O2 sensor connector.
- Connect voltmeter between O2 sensor harness terminal and ground. DO NOT apply voltage to O2 sensor.
- With engine at 1500-2000 RPM, turn WOT microswitch on by moving microswitch lever. See Fig 1
. Check that voltmeter reads about .8 volts.
Courtesy of GENERAL MOTORS CORP.
- With engine at 1000-1500 RPM, disconnect vacuum hose at intake manifold. Check that voltmeter reads near zero. Reconnect vacuum hose and O2 sensor connector.