P0474moderate severityPowertrain
Exhaust Pressure Control Valve Circuit Intermittent
on 2000 Audi A6 2.7L Turbo V6 · AWD
What this code means
The exhaust pressure control valve circuit shows an intermittent fault. The signal drops out or fluctuates, common on diesels with exhaust backpressure valves.
Symptoms
- Check engine light on
- Rough running or reduced power
- Poor cold-start performance
Common causes
- Loose or corroded connector
- Damaged wiring harness
- Faulty exhaust pressure control valve
- Bad PCM
Diagnostic steps
- Read code and check freeze frame
- Wiggle-test wiring and connectors
- Monitor valve signal for dropouts
- Repair wiring or replace valve
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