Oxygen Sensor Heater Bank 1 Sensor 2, Checking

Special tools and workshop equipment required 

• multimeter.
• Wiring diagram.

Test requirements

• The HO2S Oxygen Sensor Bank 1 Sensor 2 -G130- 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 

-- Observe Clean Working Conditions. Refer to CLEAN WORKING CONDITIONS 

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

Start diagnosis

Checking internal resistance 

-- Disconnect the HO2S Oxygen Sensor Bank 1 Sensor 2 -G130- electrical harness connector -1-.

-- Using a multimeter, check the Oxygen Sensor Heater Bank 1 Sensor 2 -Z29- terminals 1 to 2 for resistance.

Specified value: 1.0 to 20.0 Ω (at approx. 20° C)

If the specification was not obtained:

-- Replace the faulty HO2S Oxygen Sensor Bank 1 Sensor 2 -G130-. 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 1 Sensor 2 -Z29- electrical harness connector terminal 1 to ground for voltage.

Specified value: 10.10 to 11.70 V

Switch the ignition off.

If the specification was not obtained:

-- Check the wiring from fuse 45 in Fuse Panel B to the O2S heater terminal 1 for high resistance, a short circuit 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 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-. Refer to the Repair information.

-- Using a multimeter, check the Oxygen Sensor Heater Bank 1 Sensor 2 -Z29- electrical harness connector to the Engine Control Module (ECM) -J623- electrical harness connector T94 for an open circuit.

Oxygen Sensor Heater Bank 1 Sensor 2 -Z29- electrical harness connector terminal	Engine Control Module (ECM) -J623- electrical connector T94 terminal or test box socket
2	7

Specified value: 1.5 Ω 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.

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to READINESS CODE .

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-. 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 .
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 .