Control Checking - Heated Oxygen Sensor

HEATED OXYGEN SENSOR (HO2S) AND OXYGEN SENSOR CONTROL, CHECKING.

Test using VAG 1551 Scan Tool (ST) with engine idling.

^ Engine basic setting OK

^ Exhaust system not leaking between Three Way Catalytic converter (TWC) and cylinder head.

Voltage Supply for Heated Oxygen sensor heater circuit OK => Repair Group 01, Output Diagnostic Test Mode.

^ VAG 1551 Scan Tool connected. Go to "Read Measuring Value Block" function (08) display group 01 => Repair group 01.




Indicated on display (1-4 = display fields)



Continue testing only when:

^ Engine Coolant Temperature is over 80°C (176°F - channel 2)

^ Engine has run 2 minutes at idle

- Read Oxygen Sensor factor in channel 3.

^ Value displayed fluctuates up and down If value in channel 3 does not fluctuate:

- Insure that HO2S heater is functioning properly.

- Briefly raise engine speed above 2000 rpm and repeat test.

- Press buttons -0- and -6- to select Function "End Output".

- Press -0- to confirm input.

If Oxygen Sensor display 1.00 does not change even during acceleration:

- Disconnect harness connector from Engine Coolant Temperature Sensor.

- Press buttons -0- and -5- to select Function "Erase DTC Memory".

- Press -Q- to confirm input.

- Unplug Heated Oxygen sensor harness connector.




- Connect adapter lead from VW 1594 to cavity 4 (wiring to Motronic Engine Control Module J220) and hold to Ground (GND).

^ Value in channel 3 must increase.

If YES:

- Replace Heated Oxygen Sensor.


If NO:

- Perform VAG 1598 Electrical test of wiring to HO2S, Test Step 16, Repair Group 01, page 01-34

- Contact VW Technician's Helpline if it is necessary to replace Motronic Engine Control Module (ECM) (J220) -> page 24-7, item 14.

- Connect Engine Coolant Temperature

Sensor.

- Press -> button

- Press buttons -0- and -5- buttons to select Function "Erase DTC Memory".

- Press -Q- to confirm input.

- Press -> button

- Press buttons -0- and -6- to select Function "End output".

- Press -Q- to confirm input.