P048DExhaust Pressure Control Valve A Position Sensor/Switch Circuit Low
- 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. P048D means valve A's position signal is below its permitted voltage window – the signal wire is shorted to ground or the sensor's 5 V supply is missing. Bentley's Continental and Flying Spur V8 of 2023 report it for bank 1 together with P048B; the bulletin advises checking wiring and contacts, otherwise replacing the actuator and carrying out the basic setting.
- What you may notice
- Check engine light on
- Flap without function, exhaust sound changed
- VW/Audi TDI: EGR fault P0401 possible
- Likely causes
- LikelySignal wire shorted to ground (chafed at the underbody)
- LikelyPosition sensor or actuator faulty internally
- Possible5 V sensor supply open or shorted
- PossibleMoisture or corrosion 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: €100 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.