Ho2S Front Oxygen Sensor Bank 2 Sensor 1, Checking

The following procedure is used to diagnose both HO2S Oxygen Sensor Bank 1 Sensor 1 -G39- and HO2S Oxygen Sensor Bank 2 Sensor 1 -G108-

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements

• The Oxygen Sensor Heater Bank 2 Sensor 1 -Z28- fuse OK.
  Fig 1: Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• The Oxygen Sensor Heater Bank 2 Sensor 1 -Z28- before catalytic converter OK. Refer to.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Exhaust system between catalytic converter and cylinder head properly sealed.
• Coolant Temperature at least 80° C.

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 .

Function test 

-- Perform the function test in Diagnostic Mode 06. Refer to DIAGNOSTIC MODE 06 - READ TEST RESULTS FOR SPECIFIC DIAGNOSTIC FUNCTIONS .

-- Switch the ignition off.

If the specified values were not obtained:

Start Diagnosis 

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

Checking primary voltage 

-- Using a multimeter, check the HO2S Oxygen Sensor Bank 2 Sensor 1 -G108- electrical harness connector terminals 1 to 5 for voltage.

Specified value: 0.40 to 0.50 V

-- Switch the ignition off.

If the specified value was obtained:

-- Replace the HO2S Oxygen Sensor Bank 2 Sensor 1 -G108-.

If the specified value was not 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 the Repair information.

-- Using a multimeter, check the HO2S Oxygen Sensor Bank 2 Sensor 1 -G108- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T94 terminals for an open circuit.

HO2S Oxygen Sensor Bank 2 Sensor 1 -G108- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals or test box sockets
1	59
2	84
3	73
5	83
6	62

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:

Generate readiness code. Refer to READINESS CODE .

If the DTC does return, no malfunction is detected in the wiring and the voltage supply is 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 .