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Oxygen Sensor (O2S) 1 (Behind Three Way Catalytic Converter (TWC)) Heater Z29 , Checking



Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC)) Heater Z29, Checking

The following procedure is used to diagnose Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC)) Heater Z29 for Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 which is controlled by the Motronic Engine Control Module (ECM) J623.

NOTE: When servicing terminals in harness connector of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) use only gold-plated terminals.

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

Test requirements
- Fuse S73 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.

Procedure
- Raise the vehicle.







- Disconnect the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector - 1 -.

Checking internal resistance







- Using a multimeter , check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 terminals 1 to 2 for resistance.
Specified value: 1.0 to 20.0 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 wiring from the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130 electrical harness connector terminal 1 to the Engine Component Power Supply Relay J757 socket 2/87 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.

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 to the Motronic Engine Control Module (ECM) J623 electrical harness connector T94 for an open circuit.

Oxygen Sensor (O2S) Motronic Engine Control
Behind Three Way Catalytic Module (ECM) J623
Converter (TWC) G130 electrical connector
electrical harness connector T94 terminal or test

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).
- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and if the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) J623.

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
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code.

- End of diagnosis.

Oxygen Sensor (O2S) 2 (behind Three Way Catalytic Converter (TWC)) Heater Z30, Checking

The following procedure is used to diagnose Oxygen Sensor (O2S) 2 (behind Three Way Catalytic Converter (TWC)) Heater Z30 for Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 which is controlled by the Engine Control Module (ECM) 2 J624.

NOTE: When servicing terminals in harness connector of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) use only gold-plated terminals.

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

Test requirements
- Fuse S73 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.

Procedure
- Raise the vehicle.







- Disconnect the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 electrical harness connector - 3 -.

Checking internal resistance







- Using a multimeter , check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 terminals 1 to 2 for resistance.
Specified value: 1.0 to 20.0 Ohms (at approx. 20 degrees C)

If the specification was not obtained:
- Replace the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131.

If the specification was obtained:

Checking voltage supply
Crank the engine.







- Using a multimeter, check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 electrical harness connector terminal 1 to Ground (GND) for voltage.

Oxygen Sensor (O2S) 2 Behind Measure to
Three Way Catalytic Converter
(TWC) G131 electrical harness
connector terminal

1 Ground (GND)

Specified value: Battery voltage.
Switch the ignition off.

If the specification was not obtained:
- Check the wiring from the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 electrical harness connector terminal 1 to the Engine Component Power Supply Relay J757 socket 2/87 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.

If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) 2 J624.







- Using a multimeter , check the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 electrical harness connector to the Engine Control Module (ECM) 2 J624 electrical harness connector T94a for an open circuit.

Oxygen Sensor (O2S) 2 Behind Engine Control Module
Three Way Catalytic Converter (ECM) 2 J624 electrical
(TWC) G131 electrical harness connector T94a terminal
connector terminal or test 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).
- 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) 2 J624.

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
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code.

- End of diagnosis.