OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P25D6

Exhaust Heat Exchanger Exhaust Bypass Valve A Position Sensor Stop Performance

During self-calibration of the exhaust heat exchanger bypass valve A, the position sensor never reached the expected mechanical stop. The controller cannot zero the position reference, so commanded openings will be inaccurate.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / D6

Possible causes

  • Soot or carbon deposits prevent valve from reaching the stop high
  • Worn linkage between actuator and valve flap medium
  • Position sensor not aligned with valve shaft medium

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 250–1500 €
  • Estimated time: 1.5–5 h
  • Component: exhaust heat exchanger
  • Component: bypass valve actuator
  • Component: position sensor
  • MIL / check engine light
  • emissions-relevant

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication