Oxygen Sensor Heater Bank 2 Sensor 1, Checking

Oxygen Sensor Heater Bank 2 Sensor 1, Checking

• Oxygen Sensor Heater Bank 2 Sensor 1 (Z28) is part of HO2S Oxygen Sensor Bank 2 Sensor 1 (G108) and cannot be serviced separately.

• When servicing terminals in the electrical harness connector of HO2S Oxygen Sensor Bank 2 Sensor 1 (G108) , use only gold-plated terminals.

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (SB-12) 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 connections between engine/transmission/chassis OK.

• Ignition switched Off.

Test procedure

- Observe safety precautions. Refer to => [ Safety Precautions ] Safety Precautions

- Observe Clean Working Conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions

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

Start diagnosis

- Disconnect the HO2S Oxygen Sensor Bank 2 Sensor 1 (G108) electrical harness connector- 4 -.

Checking internal resistance

- Using a multimeter, check the Oxygen Sensor Heater Bank 2 Sensor 1 (Z28) terminals 3 to 4 for resistance.

Specified value: 2.5 to 10.0 ohms (at approx. 20° C)

If the specification was Not obtained:

- Replace HO2S Oxygen Sensor Bank 2 Sensor 1 (G108). Refer to the repair information.

If the specification was obtained:

Checking voltage supply

Switch the ignition On.

- Using a multimeter, check the Oxygen Sensor Heater Bank 2 Sensor 1 (Z28) electrical harness connector terminal to ground for voltage.






Specified value: above 9.50 V.

Switch the ignition Off.

If the specification was Not obtained:

- Check the Oxygen Sensor Heater Bank 2 Sensor 1 (Z28) electrical harness connector terminal 4 to fuse 12 in Fuse Panel B for high resistance, a short to ground, or an open circuit.

- 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 wiring

- Remove the Engine Control Module (ECM) (J623). Refer to the repair information.

- Using a multimeter, check the Oxygen Sensor Heater Bank 2 Sensor 1 (Z28) electrical harness connector 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 high resistance, an open or a short to voltage 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 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 mentioned sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

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