Operation CHARM: Car repair manuals for everyone.

With Manufacturer's Scan Tool




Special tools and equipment required
- Scan tool VAG 1551 or vehicle system tester VAG 1552 with cable VAG 1551/3
- Test box VAG 1598/31
- Hand multimeter VAG 1526 or multimeter VAG 1715
- Adapter set VAG 1594

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 engine must be running at idling speed.
(Connecting scan tool and selecting engine control module). Refer to "VAG 1551 Scan Tool" [1][2][3][4][5]Connecting VAG 1551 Scan Tool.

Indicated on display:


Rapid data transfer HELP
Select function XX



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

Indicated on display:


Read measured value block HELP
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 measured value block 41 ->
1 2 3 4


- Check Oxygen sensor heater status in display zone 4:
Display: Htg.aC.ON, Htg.aC.OFF (alternating)

If the display does not indicate as described:







- Remove protective cover -arrows- and separate 4-pin connector (brown) to Oxygen sensor after catalyst (G130).







- Check probe heating for continuity at Oxygen sensor connector contacts 1 and 2.

If it is determined that probe heating has an open circuit:
- Replace the Oxygen sensor after catalyst (G130).

If probe heating has continuity:







- Set multimeter to measure voltage and connect to contacts 1 and 2 on connector to control module.
- Start engine and run at idling speed.
- Measure voltage supply:

When display group 41, display zone 4 displays: Display, Htg.aC.ON:

Specification: 11.0 - 14.5 V

Display, Htg.AC.ON/Htg.AC.OFF (alternating)

Specification: Between 0.0 - 12.0 V fluctuating

- Switch off ignition.

If no voltage is present:







- Connect test box VAG 1598/31 to control module wiring harness. The engine control module remains disconnected.







- Check wiring between test box and 4-pin connector for open circuit using wiring diagram.
Contact 2 and socket 63
Wire resistance: Max. 1.5 ohms

If the specification is obtained:
- Check wiring from contact 1 to fuel pump relay (J17) according to wiring diagram.