P2104critical severityPowertrain
Throttle Actuator Control System Forced Idle
on 2008 Audi R8 4.2L V8 · AWD
What this code means
ECM has forced the engine to idle speed only due to a detected throttle control fault.
Symptoms
- Engine stuck at idle
- Check engine light
- Vehicle barely moves
- Traction control light on
Common causes
- Throttle body failure
- APP sensor fault
- Wiring issue
- ECM detected conflicting throttle signals
Diagnostic steps
- Scan for other DTCs
- Check APP sensor signals
- Inspect throttle body
- Clear codes and test
Repair notes
Diagnose root cause from accompanying DTCs. This is a protective measure.
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