With Manufacturer's Scan Tool

Oxygen Sensor (02S) Heater (Behind TWC) , Checking


NOTE:
- Harness connector for Oxygen Sensor (O2S) heater: 4-pin, black
- Component locations


Required special tools and test equipment
- VAG 1551 or VAG 1552 Scan Tool (ST) with VAG 1551/3 adapter cable
- VAG 1598/22 test box
- Multimeter US 1119 (Fluke 83 or equivalent)
- VW 1594 connector test kit
- Wiring diagram

Test requirements
- Fuse for Oxygen Sensor (02S) heater OK
- Engine Coolant Temperature (ECT) at least 85 °C (185 °F)

Checking
- Connect VAG 1551 or VAG 1552 scan tool and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle). Connecting VAG 1551/1552 Scan Tool

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.

Indicated on display


Read Measuring Value Block HELP
Input display group number XXX


- Press buttons -0-, -4- and -1- to input display group number 41, and press -Q- button to confirm input.

Indicated on display (1-4 = display fields)


Read Measuring Value Block 41 ->
1 2 3 4


- Compare display and specified values (display fields 3 and 4):

Display Group 41:

If displayed values are OK (as specified):
- Press -> button to advance program sequence.
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.
- Switch ignition off.

Continuation
- Disconnect 4-pin connector (black) for Oxygen Sensor (02S) 2 -G108- behind Three Way Catalytic Converter (TWC).







- Connect multimeter US 1119 (Fluke 83 or equivalent) between HO2S connector terminals 1 and 2, using VW 1594 connector test kit.
- Measure resistance.
Specified value: 0.00 - 19.9 Ohms

If resistance is NOT OK:
- Replace Heated Oxygen Sensor (HO2S) behind TWC -G108-.

If resistance is OK:
- Switch multimeter to 20 VDC measuring range.







- Connect multimeter between harness connector terminals 1 and 2 (to ECM), using VW 1594 connector test kit.
- Measure voltage supply and check display in display group 41, display field 4.

If display = Htg.aC.ON:
- Specified value: 11.0 - 14.5 volts

If display is switching between "Htg.aC.ON" and "Htg.aC.OFF"
- Specified value: 0.0 - 12.0 volts (oscillating)

If there is no voltage:







- Connect multimeter between harness connector terminal 1 (to ECM) and vehicle Ground, using VW 1594 connector test kit.
Specified value: 11.0 - 14.5 volts

If there is still no voltage:
- Check wiring between terminal 1 and relay panel using appropriate wiring diagram.

If there is voltage:







- Connect multimeter between harness connector terminal 2 (to ECM) and Battery Positive Voltage (B+), using VW 1594 connector test kit.
- Measure voltage supply and check display in display group 41, display field 4.

If display = Htg.aC.ON:
- Specified value:11.0 - 14.5 volts

If display switches between "Htg.aC.ON" and "Htg.aC.OFF:"
- Specified value: 0.0 - 12.0 volts (oscillating)
- Switch ignition off.

If there is no voltage:
- Connect VAG 1598/22 test box to ECM harness connector. Connecting VAG 1598/22 Test Box







- Check wiring for open circuit between ECM/test box and 4-pin HO2S harness connector (to ECM).
- Connector terminal 2 to ECM/test box socket 28
- Specified value: max. 1.5 Ohms

If wiring is OK:
- Replace ECM -J220-
- Carry out adaptation of throttle valve control module to ECM.
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code.
Readiness Code Reading
Readiness Code, Generating