Oxygen Sensor (O2) Test
- Warm engine to operating temperature. Run engine at fast idle. Disconnect O2 sensor. Connect a high impedance voltmeter between O2 sensor terminal "A" and ground. See Fig 1
.
- Observe voltmeter while rapidly accelerating and decelerating engine speed. Voltage should be 0.5-1.0 volt while accelerating and 0-0.4 volt while decelerating. If sensor is not operating to specifications, replace O2 sensor. Ensure new oxygen sensor has anti-seize compound applied to threads. Tighten sensor to 21-36 ft. lbs. (29-49 N.m).
Courtesy of MAZDA MOTORS CORP.