OXYGEN SENSOR HEATERS, CHECKING Audi A3 8P facelift

OXYGEN SENSOR HEATERS, CHECKING

The following procedure is used to diagnose Oxygen Sensor (O2S) Heater -Z19- for Heated Oxygen Sensor (HO2S) -G39- and Oxygen Sensor (O2S) 2 Heater -Z28- for Heated Oxygen Sensor (HO2S) 2 -G108-.

Note. When servicing electrical harness connector terminals for the Heated Oxygen Sensor (HO2S) -G39-, use only gold-plated terminals.

Special tools and workshop equipment required

1. Multimeter.
2. Wiring diagram.

Test requirements

1. The Oxygen Sensor (O2S) Heater -Z19- for Heated Oxygen Sensor (HO2S) -G39- and Oxygen Sensor (O2S) 2 Heater -Z28- for Heated Oxygen Sensor (HO2S) 2 -G108- fuses OK.
2. Battery voltage at least 12.5 volts.
3. All electrical consumers such as, lights and rear window defroster, switched off.
4. Vehicles with automatic transmission, shift selector lever into position "P" or "N".
5. A/C switched off.
6. Ground (GND) connections between engine/transmission/chassis OK.
7. Ignition switched off.

Test procedure

Perform a preliminary check to verify the customers complaint. Refer to GENERAL DIAGNOSIS .

Start diagnosis

Remove the engine cover with air filter.

Checking internal resistance

Disconnect the Heated Oxygen Sensor (HO2S) -G39- electrical harness connector -2- or the Heated Oxygen Sensor (HO2S) 2 -G108- electrical harness connector -1-.

Scheme 18

Using a multimeter, check the Heated Oxygen Sensor (HO2S) -- terminals 3 to 4 for an open circuit.

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

If the specification was not obtained

Replace the 2- Heated Oxygen Sensor (HO2S) -G39- or the 1- Heated Oxygen Sensor (HO2S) 2 -G108-.

If the specification was obtained

Checking voltage supply

Using a multimeter, check the Heated Oxygen Sensor (HO2S) -- electrical harness connector terminal 4 to theFuel Pump (FP) 2 Relay -J49- terminal 2/87 for voltage.

Scheme 19

Specified value: Battery voltage.

If the specification was not obtained

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

Check the electrical harness connector for damage, corrosion, lose 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. Refer to Repair information.

If the manufacturers test box is not being used. Perform the following step.

Remove the Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE, REPLACING .

Using a multimeter, check the Heated Oxygen Sensor (HO2S) -- electrical harness connector to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T121 for an open circuit.

Specified value: 1.5 ohms max.

If the specification was not obtained

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

Check the electrical harness connector for damage, corrosion, lose 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 Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE, REPLACING .

Install the engine cover with air filter.

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»(ref-496052-S19620787362012082100000) .
2. If necessary, erase the DTC memory. Refer to «DIAGNOSTIC MODE 04 - ERASE DTC MEMORY»(ref-496052-S08323179062012082100000) .
3. If the DTC memory was erased, generate readiness code. Refer to «READINESS CODE»(ref-496052-S02985333272012082100000) .

End of diagnosis.