Possible cause
WARNING: This page does not describe the selected car, but rather 27 other vehicles, including the 2002 Volkswagen Cabrio, 2001 Volkswagen Cabrio, 2000 Volkswagen Cabrio, 1999 Volkswagen Jetta, and 1999 Volkswagen Golf. However, it is still accessible from the selected car via links, so may be relevant.
- DTC 17978 "Engine Control Module blocked" is stored in DTC memory, this means: The Immobilizer Control Module (ICM) has not released the ECM.
- Erase DTC memory (function 05) and end output.
- Select Immobilizer Control Module (ICM) with address word 25.
- Check DTC memory (function 02), interrogate with DTC table, and repair if necessary.
- After repair and matching immobilizer components check Engine Control Module memory and erase DTCs, if necessary.
- DTC 17978 "Engine Control Module blocked" is not stored in DTC memory, this means: No immobilizer malfunction.
- Perform On Board Diagnostic (OBD) per DTC table.