Oxygen Sensor: Testing and Inspection

OUTPUT VOLTAGE

Oxygen Sensor Testing:

1. Warm engine to operating temperature and run at idle.
2. Disconnect oxygen sensor connector. Connect voltmeter between sensor and ground.
3. Increase and decrease engine speed suddenly several times. Verify that meter reads 0.5 - 1.0V when speed is increased and 0 - 0.4V when speed is decreased.
4. If not as specified, replace sensor.

SENSITIVITY

NOTE: This test requires a chassis dynamometer and use of Mazda Self-Diagnosis Checker (SST #49 H018 9A1) or suitable aftermarket "Scan" tool.

1. Set up vehicle on dynamometer.
2. Connect test tool to check connector (Green: 6-pin) Do not ground test connector (Green: 1-pin).
3. Warm up engine and run at idle.
4. Shift into low gear.
5. Increase engine speed to 2000 - 3000 rpm. Verify that monitor lamp flashes more than 8 times during a 10 second period.
6. If not as specified, replace sensor.