Oxygen Sensor: Testing and Inspection

NOTE: Oxygen sensor problems may set Diagnostic Trouble Codes 15 and/or 17 (left side), and 23 and/or 24 (right side).

TERMINAL VOLTAGE CHECK

Oxygen Sensor Terminal Voltage:

1. Warm engine to operating temperature.
2. Connect Engine Signal Monitor (SST 49 9200 162) to PCME. Connect voltmeter to output connectors as shown.
3. Run engine at 4500 rpm until voltmeter indicates approximately 0.7V.
4. Abruptly raise and lower engine speed several times:
a. When speed is increased, meter should read above 0.5V.
b. When speed is decreased, meter should read below 0.4V.

NOTE: With brake pedal depressed, monitor lamp shows operation of right sensor. With brake pedal released. monitor lamp shows operation of left sensor.

5. If not as specified, replace sensor.

SENSITIVITY CHECK

Oxygen Sensor Sensitivity Check:

1. Warm engine to operating temperature.
2. Connect System Selector (SST 49 B019 9A0) and Self-Diagnosis Checker (SST 49 H018 9A1), or aftermarket equivalents, to data link connector.
3. Set switch "A" to position "1." Set test switch of "O2 MONITOR."
4. Raise engine speed from 2000 to 3000 rpm. Check that monitor lamp flashes at least 8 times in 10 seconds.
5. If not as specified, replace sensor.
6. Turn ignition "OFF." To erase PCME service code created during testing, disconnect battery negative terminal and depress brake pedal for at least 20 seconds.

SENSOR HEATER RESISTANCE CHECK

Oxygen Sensor Heater Resistance Check:

1. With ignition "OFF," unplug sensor connector.
2. Measure resistance across terminals "C" and "D" as shown on image.

Approx. 6 ohms @ 68°F (20°C)

3. If not as specified, replace sensor.