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WARNING: This page is about a different car, the 2002 Audi S4. However, it is still accessible from the selected car via links, so may be relevant.
Idle speed, ignition timing and ignition timing advance are controlled by the ECM and are not adjustable. When engine is idling the ECM tries constantly to adjust actual engine speed so that it matches specified value. This means that the actual engine speed when idling should always be approximately the same as the specified engine speed. If the idle speed is too high or too low, or if the engine does not idle smoothly, and there are no malfunctions stored in the DTC memory, perform the following tests:
- Check intake system for un-metered air (vacuum leaks).
- Check Throttle Valve Control Module. See AIR INDUCTION SYSTEMS in SYSTEM & COMPONENT TESTING article.
- Check EVAP canister purge regulator valve for constant open condition. Perform testing procedure under appropriate EVAP valve related DTC in appropriate SELF-DIAGNOSTICS article.
- Preform adaptation of Throttle Valve Control Module. See THROTTLE VALVE CONTROL MODULE ADAPTATION under DIAGNOSTIC FUNCTION 04 - BASIC FUNCTION in appropriate SELF-DIAGNOSTICS article.