Functional check on warning lamp

WARNING: This page is about a different car, the 2003 Audi S6 and 2002 Audi S6. However, it is still accessible from the selected car via links, so may be relevant.

Start engine.
Specified value: If no DTCs relating to the electronic throttle system are stored in the DTC memory the EPC warning lamp should illuminate for about 3 seconds after the engine is started.

If the EPC warning lamp does not illuminate:

Check wiring from engine control module to EPC warning lamp in instrument cluster.
Check DTC memory of engine control module. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING AND ERASING .