Oxygen Sensor Heater Behind Catalytic Converter, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Oxygen Sensor Behind Three Way Catalytic Converter -G130- fuse is OK.
  Fig 1: Oxygen Sensor Heater Behind Catalytic Converter, Checking

  Courtesy of AUDI OF AMERICA, LLC
• 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 

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

Start diagnosis 

-- Remove the right vehicle floor cover -arrows-.

Checking internal resistance 

-- Disconnect the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector -arrow-.

-- Using a multimeter, check the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector terminals 1 to 2 for resistance.

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

If the specified value was Not obtained:

-- Replace the Oxygen Sensor Behind Three Way Catalytic Converter -G130-. Refer to the Repair information.

If the specified value was obtained:

Checking voltage supply 

-- Turn the ignition switch ON

-- Using a multimeter, check the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector terminal 1 to engine ground.

-- Turn the ignition switch OFF.

Specified value: Battery voltage.

If the specified value was Not obtained:

-- Check the wiring from O2 heater fuse in Fuse Panel B to terminal 1 of the Oxygen Sensor Behind Three Way Catalytic Converter -G130- for an open, high resistance, short circuit or Ground. Refer to Wiring Diagrams for fuse number.

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

-- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

Checking Ground activation 

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

-- Using a multimeter, check the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector terminal 2 to the Engine Control Module (ECM) -J623- electrical harness connector T94 terminal 29 for an open circuit according to the wiring diagram.

Specified value: 1.5 Ω max.

If the specified value was Not obtained:

-- Check the wiring for an open or high resistance.

-- 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 if the voltage supply was OK:

-- Replace the Engine Control Module (ECM) -J623-. Refer to the Repair information.

-- Install the right vehicle floor cover.

Final procedures 

After the 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 .