P0479Exhaust Pressure Control Valve A Intermittent
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The exhaust pressure control valve is a flap in the exhaust: on older Navistar/Ford diesels a warm-up flap that raises back pressure when cold, on Ram and others an exhaust brake, on VW's 2.0 TDI a flap that drives the low-pressure EGR, and on Audi and Bentley a sound flap. P0479 means an intermittent circuit or function fault of valve A. No manufacturer document available to us uses this code; Audi describes its flap faults as mostly sporadic under P0475/P0477, and Bentley distinguishes intermittent from static faults in the fault memory. Typical causes are a loose contact or commutator wear in the flap motor. CARB requires output components to be monitored.
- What you may notice
- Check engine light on, possibly only after several events
- Occasional flap noise or malfunction
- Likely causes
- LikelyLoose contact in connector or wire
- PossibleFlap motor with commutator wear
- PossibleMoisture in the connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.