Oxygen Sensor (O2S) 2 Heater, Checking

The following procedure is used to diagnose the Oxygen Sensor (O2S) 2 Heater -Z28-.

Oxygen Sensor (O2S) 2 Heater -Z28- is part ofHeated Oxygen Sensor (HO2S) 2 -G108- and cannot be serviced separately.

Observe all safety precautions: SAFETY PRECAUTIONS

View clean working conditions: CLEAN WORKING CONDITIONS

Prior to repair work, perform a preliminary check to verify the condition. Refer to. PRELIMINARY CHECK

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements

• Engine Control Module -J623- fuses OK.
• Heated Oxygen Sensor (HO2S) 2 -G108- OK.
• Fuse is 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.
• Exhaust system between catalytic converter and cylinder head properly sealed.
• Coolant Temperature at least 80° C.

Start diagnosis

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK

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

Checking internal resistance

-- Using a multimeter, check the Heated Oxygen Sensor (HO2S) 2 -G108- terminals 3 to 4 for resistance.

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

If the specification was not obtained:

-- Replace Heated Oxygen Sensor (HO2S) 2 -G108-. Refer to Repair Information.

If the specification was obtained:

Checking voltage supply

-- Switch the ignition on.

-- Using a multimeter, check the Heated Oxygen Sensor (HO2S) 2 -G108- electrical harness connector terminal 4 to Ground (GND) for voltage.

Specified value: Battery voltage.

-- switch the ignition off.

If the specification was not obtained:

-- Check the electrical harness connector for damage, corrosion, lose or broken terminals.

-- Check the wiring for a short circuit to each other, Battery voltage, Ground (GND) or an open circuit.

-- If necessary, repair the faulty wiring connection.

If the specification was obtained:

Checking Ground (GND) activation

-- Remove the Engine Control Module -J623-. Refer to Repair Information.

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

Heated Oxygen Sensor (HO2S) 2 -G108- electrical harness connector T5aq terminals:	Engine Control Module -J623- electrical connector T94 terminals:
3	73

Specified value: 1.5 Ω max.

If the specification was not obtained:

-- Check the wiring for a short circuit to each other, Battery voltage, Ground (GND) or an open circuit.

-- 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 -J623-. Refer to Repair Information.

-- 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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .