P04A7Exhaust Pressure Control Valve B Position Sensor/Switch Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- An exhaust pressure control valve is an electrically driven flap in the exhaust with a position sensor or end-position switch, usually inside the actuator. Valve B is the second such flap; Bentley's V8 assigns A to bank 1 and B to bank 2. Documented uses are the flap behind the particulate filter of VW's and Audi's 2.0 TDI, which raises back pressure for the low-pressure EGR, and the sound flaps of Audi and Bentley. P04A7 means valve B's position signal is valid but does not fit the commanded position or the learned end stops. No manufacturer document available to us uses this code; the description mirrors the valve A counterpart P048C and CARB's monitoring requirement for input and output components.
- What you may notice
- Check engine light on
- Flap without function, exhaust sound changed
- VW/Audi TDI: EGR fault P0401 possible
- Likely causes
- LikelyFlap or shaft corroded or coked (stiff)
- PossibleEnd positions not relearned after replacement
- PossiblePosition sensor in the actuator drifting
- RareContact resistance 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: €150 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.