Tools needed
Safety glasses
Oxygen sensor socket/ open end wrench
Ratchet
Voltmeter
Testing
1. Check the wiring and connectors to the O2 Sensor for damage.
2. Check the intake and exhaust system leaks. Tese conditions would tend to create more oxygen in the exhaust and the PCM will add more fuel to the mixture.
3. A misfiring spark plug will cause unburned fuel and oxygen in the exhaust, which will cause the sensor to give a false lean reading.
4. Find a wiring diagram for your specific alternator. A heated O2 sensor will have 4 wires and non heated will have 2.
5. With a voltmeter, place the leads between the sensor wire and ground. The voltage should cycle from high to low around 0-1 Volts.
6. If the voltage is continually high, the air/fuel mixture is rich or the sensor is bad.
7. If the voltage is continually low, the air/fuel mixture is lean, the sensor may be bad, or the wire from the sensor to the PCM may have a high resistance.
8. If the sensor signal reads low or zero voltage, unplug the sensor. If the voltage increases while the sensor is unplugged, the sensor is most likely shorted to ground.
9. If there is no problem with the fuel mixture or if it is not shorted to ground, replace the sensor.
Replacing
1. Raise and support the vehicle.( see raising and supporting
vehicle)
2. Spray the bottom part of the sensor with penetrating oil.
3. Place the socket over the sensor and unscrew it just like a bolt. If the
bolt is rusted on there too much and penetrating oil will not work, you may
heat up the bottom of the sensor with a torch. Make sure you do not start the
wires on fire or any other part of the sensor system.
4. Once removed, take your new sensor and coat the threads with antiseize.
Screw the sensor on and tighten to torque specs.
5. Plug in all wires that you needed to disconnect.
6. Lower the vehicle and start engine and listenfor any exhaust leaks or
problems. Ensure proper function by test driving.
7. NOTE: When an oxygen sensor is not operating the catalytic converter may
be the cause. Always check the catalytic converter. If it needs replacement
see Catalytic converter replacement.
Safety glasses
Oxygen sensor socket/ open end wrench
Ratchet
Voltmeter
Testing
1. Check the wiring and connectors to the O2 Sensor for damage.
2. Check the intake and exhaust system leaks. Tese conditions would tend to create more oxygen in the exhaust and the PCM will add more fuel to the mixture.
3. A misfiring spark plug will cause unburned fuel and oxygen in the exhaust, which will cause the sensor to give a false lean reading.
4. Find a wiring diagram for your specific alternator. A heated O2 sensor will have 4 wires and non heated will have 2.
5. With a voltmeter, place the leads between the sensor wire and ground. The voltage should cycle from high to low around 0-1 Volts.
6. If the voltage is continually high, the air/fuel mixture is rich or the sensor is bad.
7. If the voltage is continually low, the air/fuel mixture is lean, the sensor may be bad, or the wire from the sensor to the PCM may have a high resistance.
8. If the sensor signal reads low or zero voltage, unplug the sensor. If the voltage increases while the sensor is unplugged, the sensor is most likely shorted to ground.
9. If there is no problem with the fuel mixture or if it is not shorted to ground, replace the sensor.
Replacing
1. Raise and support the vehicle.( see raising and supporting
vehicle)
2. Spray the bottom part of the sensor with penetrating oil.
3. Place the socket over the sensor and unscrew it just like a bolt. If the
bolt is rusted on there too much and penetrating oil will not work, you may
heat up the bottom of the sensor with a torch. Make sure you do not start the
wires on fire or any other part of the sensor system.
4. Once removed, take your new sensor and coat the threads with antiseize.
Screw the sensor on and tighten to torque specs.
5. Plug in all wires that you needed to disconnect.
6. Lower the vehicle and start engine and listenfor any exhaust leaks or
problems. Ensure proper function by test driving.
7. NOTE: When an oxygen sensor is not operating the catalytic converter may
be the cause. Always check the catalytic converter. If it needs replacement
see Catalytic converter replacement.