Component Tests and General Diagnostics

Immobilizer, Troubleshooting

Requirements

- Voltage supply OK.
- Adapter cable between control module for immobilizer and VAG 1551 OK.
- Valid wiring diagram available.

Symptom:

- Engine does not start

When started, engine starts and then switches off after approx. 1 second.

- Connect VAG 1551 Scan Tool (ST) and initiate On Board Diagnostic (OBD).
- Select Engine Control Module (ECM) using address word 01.
- Check DTC memory (function 02).

Possible cause:

- DTC 17978 "Engine Control Module (ECM) locked" is stored in DTC memory, i.e.:


NOTE: Control module for immobilizer did not reactivate the Engine Control Module (ECM)!


- Erase DTC memory (function 05) and end output.
- Select control module for anti-theft immobilizer using address word 25.
- Check DTC memory (function 02) and evaluate using DTC table if necessary.
- After completing repair work and adaptation of components of immobilizer, always conclude by checking DTC memory of Engine Control Module (ECM) and erasing DTC memory if necessary.

- DTC 17978 "Engine Control Module (ECM) locked" is not stored in DTC memory, i.e.:


NOTE: There is no malfunction in the electronic immobilizer!


- Refer to engine system troubleshooting.

Symptom:
- key adaptation malfunctioning or incorrect

DTC 01179 "key programming incorrect" is stored in DTC memory of control module for anti-theft immobilizer.

- Select control module for anti-theft immobilizer using address word 25.

Example of indication on display:


WVWZZZ70Z1H000035 VWZ1Z0Y0371425 ->


- Compare 14-digit identification number indicated at right in display with identification number on key chain.


NOTE: If the two identification numbers do not match, use the identification number indicated in the display to obtain the secret number from the corporate radio/immobilizer code retrieval system.


- Adapt all keys after entering the correct secret number.