Oxygen Sensor Heater After Catalytic Converter, Checking
Oxygen Sensor Heater after Catalytic Converter, Checking
This procedure is used to check Oxygen Sensor (O2S) Heater (Z29) or Oxygen Sensor (O2S) Heater ( Z30).
• When servicing terminals in harness connector of Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC) Heater, use only gold-plated terminals.
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) (G130) fuse OK.
• The Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G131) fuse OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position " P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ General Diagnosis ] General Diagnosis.
Start diagnosis
- Disconnect the Oxygen Sensor (O2S) Heater (Z29 ) electrical harness connector - 2 -.
To disconnect the Oxygen Sensor (O2S) Heater (Z30), perform the following steps:
- Remove the screw - arrow - retaining the coolant reservoir.
- Disconnect the Engine Coolant Level (ECL) Warning Switch (F66) electrical connector from the bottom of the coolant reservoir and set aside the coolant reservoir with the coolant hoses - 1 - and - 2 - connected.
- Disconnect the Oxygen Sensor (O2S) Heater (Z30 ) electrical harness connector - 1 -.
Checking internal resistance
- Using a multimeter, check the Oxygen Sensor (O2S) Heater terminals 1 to 2 for resistance.
Specified value: 1.0 to 20.0 ohms (at approx. 20° C)
If the specification was not obtained:
- Replace the faulty Heated Oxygen Sensor (HO2S) behind the Three Way Catalytic Converter (TWC). Refer to Fuel Injection and Ignition Repair Information.
If the specification was obtained:
Checking voltage supply
- Switch the ignition on.
- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) electrical harness connector terminal 1 to Engine Component Power Supply Relay (J757) terminal 2/87 for voltage.
- Switch the ignition off.
Specified value: Battery voltage.
If the specification was not obtained:
- Check the wiring for a short circuit to each other, Ground (GND), or an open circuit.
- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.
If the specification was obtained:
Checking Ground (GND) activation
If the manufacturers test box is being used. Perform the following step.
- Install the test box. Refer to Fuel Injection and Ignition Repair Information.
If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) (J623 ). Refer to => [ ECM, Removing and Installing ] ECM, Removing and Installing.
- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) electrical harness connector terminal 2 to the Engine Control Module (ECM) (J623) electrical harness connector T94 for an open circuit.
Specified value: 1.5 ohms max.
If the specification was not obtained:
- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring and if the voltage supply was OK:
- Replace the Engine Control Module (ECM) (J623 ). Refer to => [ ECM, Removing and Installing ] ECM, Removing and Installing.
Assembly is performed in reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.
- End of diagnosis.