Diagnostic Trouble Code (DTC) memory
WARNING: This page is about a different car, the 2001 Volkswagen Jetta, 2001 Volkswagen Golf, 2000 Volkswagen Jetta, 2000 Volkswagen Golf, and 2000 Volkswagen GTI. However, it is still accessible from the selected car via links, so may be relevant.
Check DTC memory of all control modules. Refer to Automatic test sequence