With Manufacturer's Scan Tool

Heated Oxygen Sensor (HO2S) For Oxygen Sensor After Three Way Catalytic Converter (TWC), Checking

Special tools, test equipment and auxiliary items
- VAG 1551 scan tool or VAG 1552 mobile scan tool with VAG 1551/3B cable
- VAG 1598/31 test box
- VAG 1526 hand multimeter or VAG 1715 multimeter
VAG 1594 adapter set
- Electrical Wiring Diagrams

Test conditions






- All fuses must be OK
- Battery voltage must be at least 11.5 V
- Fuel pump relay must be OK

Test sequence
- Connect VAG 1551 scan tool (or VAG 1552). Start engine and select "Address word" 01 of Motronic Engine Control Module (ECM) -J220-. Engine must be running at idle speed.

Indicated on display

Rapid data transfer HELP
Select function XX

- Press buttons -0- and -8- for function "Read measuring value block" and confirm entry with -Q- button.

Indicated on display

Read measuring value block
Input display group number XXX

- Press buttons -0-, -4- and -1- for "Display group number 41" and confirm entry with -Q- button.

Indicated on display (1 to 4 = Display zones)

Read measuring value block 41 ->
1 2 3 4

- Check status of Heated Oxygen Sensor (HO2S) behind Three Way Catalytic Converter (TWC) in display field 4: Display: Htg.aC.ON, Htg.aC.OFF (alternating)






If the specification is obtained:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.

Continuation

If the specifications are not obtained:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.






- Remove protective cover -arrows- and separate 4-pin connector (brown/black) -1- to Oxygen sensor after Three Way Catalytic Converter (TWC) -G130-.






- Set multimeter to check resistance and connect it to terminals 1 + 2 of Oxygen Sensor connector. Check Oxygen Sensor heating for continuity

If it is determined that Oxygen Sensor heating has an open circuit:
- Replace Oxygen Sensor (O2S) after Three Way Catalytic Converter (TWC) -G130-
- Check DTC Memory, if necessary, repair any malfunctions and then erase DTC memory.
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive, readiness code must be generated again.

If oxygen sensor heating has continuity:

Checking voltage supply






- Set multimeter to measure voltage and connect to terminal 1 (connector to Motronic Engine Control Module (ECM) -J220-) and Ground (GND).
- Start engine and run at idling speed.
- Check voltage supply:

Specification: 11.0 to 14.5 V

If no voltage is present:
- Check wiring from terminal 1 to Fuel Pump (FP) Relay -J17- according to Electrical Wiring Diagram.

If the specification is obtained:






- Connect multimeter using auxiliary cables from VAG 1594 to measure voltage at terminals 1 + 2 (connector to Motronic Engine Control Module (ECM) -J220-).
- Measure voltage supply and observe display group 41, display zone 4.

Display: Htg.aC.ON:
- Specification: 11.0 to 14.5 V

Display: Htg. aC.ON/Htg.aC.OFF (alternating):
- Specification: Between 0.0 to 12.0 V fluctuating

If no voltage is present:
- Switch off ignition.
- Remove inner plenum chamber cover, left






- Connect VAG 1598/31 test box to control module wiring harness. Motronic Engine Control Module (ECM) -J220- is not connected by this action.






- Check wiring for open circuit between test box and 4-pin connector according to Electrical Wiring Diagram.
terminal 2 + socket 63:
Wire resistance: Max. 1.5 Ohms

If no wiring malfunction is found:
- Replace Motronic Engine Control Module (ECM) -J220-.