See Figures 1 and 2
The oxygen sensor or Heated Exhaust Gas Oxygen (HEGO) sensor supplies the ECU with a signal which indicates a rich or lean condition during engine operation. This input information assists the ECU in determining the proper air/fuel ratio. The oxygen sensor is threaded into the exhaust manifold on all vehicles.
Except Engines Equipped With MAF Sensor
- Disconnect the oxygen sensor from the vehicle harness.
- Connect a voltmeter between the HEGO signal terminal of the oxygen sensor connector and the negative battery terminal.
- Disconnect and plug the vacuum line at the MAP sensor and set the voltmeter on the 20 volt scale.
- Apply 10-14 in. Hg (34-47 kPa) of vacuum to the MAP sensor.
- Start the engine and run it at approximately 2000 rpm for 2 minutes.
- If the voltmeter does not indicate greater than 0.5 volts within 2 minutes, replace the sensor.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Disengage the oxygen/heated exhaust gas oxygen sensor electrical connector.
- Remove the sensor from the exhaust manifold or exhaust pipes, as applicable.
- Install the sensor in the exhaust manifold or pipe.
- Engage the sensor electrical connector.
- Connect the negative battery cable.