P00D8Turbocharger/Supercharger Bypass Valve B Temperature Too High
- 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
- Bypass valve B is the electric compressor recirculation valve, mounted close to the hot compressor and turbine housing. This code reports that its temperature is too high. How the temperature is detected is not described in published manufacturer documents; a documented principle for comparable turbocharger solenoids estimates the coil temperature from current, supply voltage and duty cycle and protects the coil by limiting or switching it off. With the valve switched off, the compressor may surge when lifting off the throttle. None of the published manufacturer documents searched uses this code; the explanation follows regulations and comparable manufacturer monitors.
- What you may notice
- Check engine light on (manufacturer-dependent)
- Whistling or fluttering when lifting off the throttle
- Slight loss of power
- Likely causes
- PossibleValve energised for unusually long periods, e.g. due to boost control problems
- PossibleCoil with shorted turns or aged
- PossibleHeat shield missing or exhaust leak near the turbocharger
- RareContact resistance or supply fault distorting the estimate
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €40 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.