The Heated Oxygen Sensors (HO2S) perform the following:
The catalyst monitor sensors:
Removal & Installation
- Disconnect the negative battery cable.
- If necessary, raise and safely support the vehicle.
Disconnect the sensor electrical connector(s).
NOTEIf necessary, lubricate the sensor threads with penetrating and lock lubricant to make removal easier.
Using Special Tool 303-476, or equivalent HO2S sensor socket, remove the sensor.
Installation is the reverse of the removal procedure, noting the following:
- Apply a light coat of anti-seize lubricant to the threads of the sensor before installing it.
- Tighten the sensor to 48 Nm (35 lb-ft).
- Disconnect the Heated Oxygen Sensor (HO2S) connector. Measure the resistance between the HO2S heater and VPWR on sensor side of harness. The reading should be approximately 3-30 ohms. If resistance is not within specifications, the sensor may be faulty.
- With the engine running and HO2S sensor in place measure the voltage with digital multimeter between terminals HO2S and SIGRTN at the sensor harness. The voltage should read approximately 0.01-1.0V. If the reading is off or the voltage fluctuation is very slow suspect faulty sensor.
Check for unmetered air leaks at intake manifold gasket leaks, hoses connecting to the mass air flow (MAF) sensor assembly, PCV system. Fuel calculations can be affected by unmetered air leaks.