Oxygen Sensor Heater Z29, Checking

Oxygen Sensor Heater Z29, Checking

NOTE:
- Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC)) Heater Z29 is part of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 and cannot be serviced separately.
- Vehicle must be raised before electrical harness connector for the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 is accessible.
- When servicing terminals in harness connector of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130, use only gold-plated terminals.

Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.

Test requirements
- Fuse SB46 OK.
- The Motronic Engine Control Module (ECM) Power Supply Relay 2 J670 OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- 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. Preliminary Check

Start diagnosis







- Remove the right underbody trim - arrows -.







- Disconnect the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector - arrow -.

Checking internal resistance







- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector terminals 1 to 2 for resistance.

Specified value: 0.0 to 30.0 Ohms (at approx. 20 degrees C)

If the specification was not obtained:
- Replace the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130.

If the specification was obtained:

Checking voltage supply
- Crank the engine







- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector terminal 1 to Ground (GND) for voltage.

Oxygen Sensor (O2S) Behind Measure to
Three Way Catalytic Converter
(TWC) G130 electrical harness
connector terminal
1 Ground (GND)

Specified value: Battery voltage.

- Switch the ignition off.

If the specification was not obtained:
- Check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector terminal 1 to the Motronic Engine Control Module (ECM) Power Supply Relay 2 J670 socket 2/87 for an open circuit or short circuit to each other, Battery (+), and Ground (GND).
- Check the electrical harness connector for damage, corrosion, loose 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.

If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J623.







- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector terminal 2 to the Motronic Engine Control Module (ECM) J623 electrical harness connector T94 terminal 7 for an open circuit.

Oxygen Sensor (O2S) Behind Motronic Engine Control Module
Three Way Catalytic Converter (ECM) J623 electrical harness
G(TWC) 130 electrical harness connector T94 terminal or test
connector terminal box socket
2 7

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, loose 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 Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130.
- Erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory.
- Perform a road test to verify repair.

If the DTC does not return:
Repair complete, Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) J623.
- Assembly is performed in the reverse of the removal.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:

1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

End of Diagnosis