Oxygen Sensor and Oxygen Sensor Regulation Before Catalytic Converter,Checking

Oxygen Sensor and Oxygen Sensor Regulation before Catalytic Converter, Checking

Heated Oxygen Sensor 1

• Use only gold-plated terminals when servicing terminals in the electrical harness connectors of the Heated Oxygen Sensor (HO2S) (G39).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Motronic Engine Control Module (ECM) (J623) fuses OK.

• The Oxygen Sensor (O2S) Heater (Z19) before catalytic converter 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.

• Exhaust system between catalytic converter and cylinder head properly sealed.

• Coolant Temperature at least 80 °C.

Function test

- Perform the function test located in diagnostic mode 06. Refer to => [ OBDMID 01 ($01): Oxygen Sensor
Monitor Bank 1 - Sensor 1 ] Diagnostic Mode 06 - Read Test Results For Specific Diagnostic Functions.

If specified values are obtained:

- End diagnosis and switch the ignition off.

If the specified values are not obtained:

Procedure

- Remove the rear engine cover - arrows -.

- Remove the vacuum lines - 3 - and - 4 - from the air guide hose.

- Disconnect the Mass Air Flow (MAF) Sensor (G70) electrical harness connector - 1 -.

- Loosen the hose clamps - 2 - and - 5 - and remove the air guide hose.

- Disconnect the Heated Oxygen Sensor (HO2S) (G39) electrical harness connector - 1 -.

Checking primary voltage

- Crank the engine.

- Using a multimeter, check the Heated Oxygen Sensor (HO2S) (G39) electrical harness connector terminals 2 to 6 for voltage.

Specified value: 0.400 to 0.500 Volts

- Switch the ignition off.

If the specified value was not obtained:

- Replace Heated Oxygen Sensor (HO2S) (G39).

If the specified value was 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 Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Removing and Installing ] Service and Repair.

- Using a Multimeter, check the Heated Oxygen Sensor (HO2S) (G39) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T94 terminals 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 found in the wiring:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Removing and Installing ] Service and Repair.

Assembly is performed in the reverse order of 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 Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End of diagnosis.

Heated Oxygen Sensor 2

• Use only gold-plated terminals when servicing terminals in the electrical harness connectors of the Heated Oxygen Sensor (HO2S) 2 (G108).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Motronic Engine Control Module (ECM) (J623) fuses OK.

• The Oxygen Sensor (O2S) 2 Heater (Z28) before catalytic converter 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.

• Exhaust system between catalytic converter and cylinder head properly sealed.

• Coolant Temperature at least 80 °C.

Function test

- Perform the function test located in diagnostic mode 06. Refer to => [ OBDMID 05 ($05): Oxygen Sensor Monitor Bank 2 - Sensor 1 ] .

If specified values are obtained:

- End diagnosis and switch the ignition off.

If the specified values are not obtained:

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.

Start diagnosis

- Remove the rear engine cover - arrows -.

- Disconnect the Heated Oxygen Sensor (HO2S) 2 (G108) electrical harness connector - 3 -.

Checking primary voltage

- Using a multimeter, check the Heated Oxygen Sensor (HO2S) 2 (G108) electrical harness connector terminals 2 to 6 for voltage.

Specified value: 0.400 to 0.500 Volts

- Switch the ignition off.

If the specified value was not obtained:

- Replace the Heated Oxygen Sensor (HO2S) 2 (G108).

If the specified value was 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 Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Removing and Installing ] Service and Repair.

- Using a Multimeter, check the Heated Oxygen Sensor (HO2S) 2 (G108) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T94 terminals for an open circuit.