Heated oxygen sensors are located in the exhaust pipes below the exhaust manifolds. The sensors react with the oxygen in the exhaust gases and generates a voltage based on this reaction. A low voltage indicates too much oxygen or a lean condition, while a high voltage indicates not enough oxygen or a rich condition.
- Disconnect the Oxygen Sensor (O 2 S). Measure resistance between PWR and GND (heater) terminals of the sensor. If the reading is about 6 ohms at 68°F (20°C). the sensor's heater element is okay.
- With the O 2 S connected and engine running, measure voltage with DVOM between terminals HO 2 S and SIG RTN (GND) of the oxygen sensor connector. If the voltage readings are about equal to those in the table, the sensor is okay.
- Disconnect the HO2S.
- Measure the resistance between PWR and GND terminals of the sensor. Resistance should be approximately 6 ohms at 68°F (20°C). If resistance is not within specification, the sensor's heater element is faulty.
- With the HO2S connected and engine running, measure the voltage with a Digital Volt-Ohmmeter (DVOM) between terminals HO2S and SIG RTN (GND) of the oxygen sensor connector. Voltage should fluctuate between 0.01-1.1 volts. If voltage fluctuation is slow or voltage is not within specification, the sensor may be faulty.
REMOVAL & INSTALLATION
See Figure 1
- Disconnect the negative battery cable.
- Raise and safely support the vehicle.
- Disconnect the heated oxygen sensor from the engine control sensor wiring.
If excessive force is needed to remove the sensors, lubricate the sensors with penetrating oil prior to removal.
- Remove the sensors from the Y pipe or left manifold with a sensor removal tool T94P-9472-A or equivalent.
- Install the sensor in its correct location, tighten to 26-34 ft. lbs. (36-46 Nm).
- Connect the sensor electrical wiring.
- Lower the vehicle.
- Connect the negative battery cable.