P04A0Exhaust Pressure Control Valve B 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. P04A0 is the function check of valve B: it is electrically sound but does not reach its target or full travel. Bentley documents it on the V8 of 2023 for bank 2 (with P04A8) and on the Bentayga (with P049F): the code sets when the actuator does not run through its full range, caused by sludge at the commutator or a stiff flap.
- What you may notice
- Check engine light on
- Flap without function, exhaust sound changed
- VW/Audi TDI: EGR fault P0401 possible
- Likely causes
- LikelyFlap actuator worn, commutator dirty
- PossibleFlap shaft stiff (corrosion, deposits)
- PossibleWiring or contacts
- RareBasic setting not carried out
- 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: €200 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.