P0498moderate severityPowertrain
Evaporative Emission System Vent Valve Control Circuit Low
on 2002 Audi A6 3.0L V6 · AWD
What this code means
The PCM detects low voltage in the EVAP vent valve control circuit. This can prevent the vent valve from operating correctly during leak tests.
Symptoms
- Check engine light on
- Failed EVAP monitor
- No noticeable driving symptoms
Common causes
- Short to ground in vent valve wiring
- Faulty vent valve solenoid
- Corroded connector at vent valve
- Faulty PCM driver circuit
Diagnostic steps
- Scan and record freeze frame data
- Inspect vent valve wiring and connector
- Measure vent valve circuit voltage
- Test vent valve solenoid resistance
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