P048BExhaust Pressure Control Valve A Position Sensor/Switch Circuit
- 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 A is the first 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. P048B is the general circuit fault or open circuit of valve A's position sensor or end switch. VW's 2.0 TDI of 2009–13 sets it with a corroded flap; on the 2015 engine it appears with P048E, P0475, P0477 and P0478 and the actuator with its integrated electronics is replaced; Bentley's V8 of 2023 reports it for bank 1 together with P048D. As the sensor sits in the actuator, a circuit fault often means actuator electronics.
- What you may notice
- Check engine light on
- Flap without function, exhaust sound changed
- VW/Audi TDI: EGR fault P0401 possible
- Likely causes
- LikelyActuator with integrated position sensor faulty
- LikelyConnector or wire at the underbody corroded, chafed or open
- RareEngine module (sensor supply or input)
- 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 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.