With Manufacturer's Scan Tool

Heated Oxygen Sensor (HO2S) -G39-, Checking

NOTE: Only gold-plated contacts must be used to repair the contacts in the oxygen sensors connectors.

Special tools, test equipment and auxiliary items

- Scan tool VAG 1551 or vehicle system tester VAG 1552 with cable VAG 1551/3B
- Test box VAG 1598/31
- Multimeter (Fluke 83 or equivalent)
- Adapter set VAG 1594
- Wiring diagram

Check conditions






- Fuse 43 must be OK
- The battery voltage must be at least 11.5 V
- Fuel pump relay must be OK

Test sequence

- Connect scan tool VAG 1551 (VAG 1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idle speed. Connecting scan tool and selecting engine control module. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG 1551 Scan Tool", Testing and Inspection

Indicated on display

Rapid data transfer HELP
Select function XX


- Press keys 0 and 8 for the function "Read measuring value block" and confirm entry with Q key.

Indicated on display

Read measuring value block
Input display group number XXX

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

Indicated on display (1-4 = Display zones)

Read measuring value block 41 ->
1 2 3 4

- Check status of HO2S in display field 2.

Display Group 41:

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

Continuation

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






- Remove protective cover -arrows- and separate 6-pin connector (black) -1- HO2S -G39-.

Checking voltage supply






- Connect multimeter using auxiliary cables from VAG 1594 to measure voltage at contacts 3 and 4 (connector to engine control module).
- Start engine and run at idle speed.
- Measure voltage supply and observe the display group 41, display zone 2.

Display: Htg.bC.ON:
Specification: 11.0 - 14.5 V

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

- Switch off ignition.

If no voltage is present:
- Remove inner plenum chamber cover, left:






- Connect test box VAG 1598/31 to control module wiring harness. The engine control module is not connected by this action.






- Check wiring for open circuit between test box and 6-pin connector according to wiring diagram.
Contact 4 + socket 5
Wire resistance: Max. 1.5 Ohms

If the specification is obtained:
- Check wire for open circuit between 6-pin connector contact 3 and fuel pump relay -J17- using wiring diagram.
Wire resistance: max. 1.5 Ohms