Oxygen Sensor O2S Heater, Bank 1, Sensor 1, Checking

Observe all safety precautions: SAFETY PRECAUTIONS .

View clean working conditions: CLEAN WORKING CONDITIONS .

For wiring diagrams, component locations, and connector views, Refer to the appropriate System Wiring Diagram.

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Oxygen Sensor (O2S) Heater -Z19- fuse OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched OFF.
• A/C switched OFF.
• Ground (GND) connections between engine/transmission/chassis OK.
• Exhaust system between catalytic converter and cylinder head properly sealed.
• Coolant Temperature at least 80° C.

Test procedure 

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

Start diagnosis 

-- Remove the engine covers. Refer to the appropriate Service Information.

Fig 1: Engine Cover -1- And -2-

Courtesy of AUDI OF AMERICA, LLC

Checking internal resistance 

-- Disconnect the Heated Oxygen Sensor (HO2S) -G39- / Oxygen sensor heater -Z19- electrical harness connector -2-.

Fig 2: Identifying Heated Oxygen Sensor Connector

Courtesy of AUDI OF AMERICA, LLC

-- Using a Multimeter, check the Heated Oxygen Sensor (HO2S) -G39- electrical harness connector T6a terminals 3 to 5 for resistance.

Specified value: 4.0 to 13.0 Ω (at Approx. 20 °C).

If the specified value was Not obtained:

-- Replace the Heated Oxygen Sensor (HO2S) -G39- / Oxygen sensor heater -Z19-. Refer to the appropriate Service Information.

-- Go to Final procedures.

If the specified value was obtained:

Checking voltage supply 

-- Switch the ignition ON.

-- Using a Multimeter, check the Oxygen sensor heater -Z19- electrical harness connector T6a terminal 5 to Ground (GND) for voltage.

-- Switch the ignition OFF.

Specified value: Battery voltage.

If the specified value was Not obtained:

-- Check the Oxygen sensor heater -Z19- electrical harness connector T6a terminal 5 to Fuse SA10 in Fuse Panel A Connector or an open circuit, a short circuit to each other or Ground (GND).

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

-- If necessary, repair the faulty wiring connection.

-- Repair the circuit and replace any open fuses.

-- Go to Final procedures.

If the specified value was obtained:

Checking Ground (GND) activation 

-- Remove the Engine Control Module - J623 -. Refer to the appropriate Service Information.

-- Using a Multimeter, check the Oxygen sensor heater -Z19- electrical harness connector T6a to the Engine Control Module - J623- electrical harness connector T94 for resistance.

Specified value: 1.5 Ω max.

If the specified value was Not obtained:

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

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

-- If necessary, repair the faulty wiring connection.

-- Go to Final procedures.

If the specified value was obtained:

-- Replace the Engine Control Module - J623-. Refer to the appropriate Service Information.

Final procedures 

-- Reinstall the engine covers, if necessary. Refer to the appropriate Service Information.

-- For connector location, removal and installation procedures. Refer to the appropriate Service Information.

-- 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