OBD-II code · Powertrain (generic, extended)

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.

Is it safe to drive with P25D6?

Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.

Common causes

  • Most likelySoot or carbon deposits prevent valve from reaching the stop
  • PossibleWorn linkage between actuator and valve flap
  • PossiblePosition sensor not aligned with valve shaft

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
1.5–5 h
Emissions test
Likely to fail
Parts involved
Exhaust Heat Exchanger, Bypass Valve Actuator, Position Sensor

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.