P0088high severityPowertrain
Fuel Rail/System Pressure - Too High
on 2004 Audi A6 3.0L V6 · AWD
What this code means
The fuel rail pressure is higher than the PCM commanded value.
Symptoms
- Check Engine Light
- Hard starting
- Rich running
- Injector damage risk
- Black exhaust smoke
Common causes
- Faulty fuel pressure regulator
- Restricted fuel return line
- Stuck fuel pressure relief valve
Diagnostic steps
- Monitor fuel pressure with scan tool
- Test fuel pressure regulator
- Check return line for restriction
- Inspect relief valve
Repair notes
Replace fuel pressure regulator or clear fuel return restriction.
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