P0403moderate severityPowertrain
EGR Control Circuit
on 2008-2015 Audi R8 4.2L V8 · AWD
What this code means
Malfunction in the EGR valve control circuit (electrical EGR valves).
Symptoms
- Check Engine Light
- EGR not functioning
- Increased emissions
Common causes
- Faulty EGR valve
- Wiring damage
- PCM driver failure
- Corroded connector
Diagnostic steps
- Test EGR valve solenoid resistance
- Check wiring
- Command EGR with scan tool
- Test PCM output
Repair notes
Replace EGR valve or repair wiring.
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