Oxygen Sensor Regulation in Center Three Way Catalytic Converter, Checking
Oxygen Sensor Regulation in Center Three Way Catalytic Converter, Checking
• Use only gold-plated terminals when servicing terminals in the electrical harness connectors of the Oxygen Sensor (O2S) 2 in center Three Way Catalytic Converter (TWC) (G465).
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• Fuse 21 in Fuse Panel B is OK.
• Engine Control Module (ECM) (J623) fuses 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 connections between engine/transmission/chassis OK.
• Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Start diagnosis
- Connect scan tool.
- Start the engine and let it run at idle.
- Select "Diagnostic mode 6: Check test results of components that are not continuously monitored".
- Select Monitor-ID $02: Oxygen sensor monitoring before catalytic converter.
- Check the values at idle and compare to the Monitor-ID $02 tables. Refer to => [ Monitor-ID $02: Oxygen Sensor Monitor Bank 1- Sensor 2 ] Diagnostic Modes 01 - 0A.
If the specified value was obtained:
- Turn the ignition OFF. Fault is not active at this time. Check for poor connections, loose terminals and harness check.
If the specified value was Not obtained:
Checking primary voltage
- Disconnect the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G465) electrical harness connector.
- Switch the ignition ON.
- Using a multimeter, check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G465) electrical harness connector terminals 3 to 4 for voltage.
Specified value: 0.400 to 0.500 Volts
- Switch the ignition OFF.
If the specified value was obtained:
- Replace the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G465). Refer to the Repair Information.
If the specified value was Not obtained:
Checking wiring
If the manufacturers test box is being used, perform the following step.
- Install the test box.
If the manufacturers test box is not being used, perform the following step.
- Remove the Engine Control Module (ECM) (J623). Refer to the Repair Information.
- Using a multimeter, check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) (G465) electrical harness connector terminals to the Engine Control Module (ECM) (J623) electrical harness connector T94 terminals for resistance.
Specified value: 1.5 ohms Max.
If the specified value was Not obtained:
- Check the wiring for an open, high resistance, short circuit to each other, Battery positive or Ground.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring:
- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 0A.
- Perform a road test to verify active fault.
If the DTC does Not return:
Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Engine Control Module (ECM) (J623). Refer to the Repair Information.
- Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 0A.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 0A.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.