Powertrain, generic (extended)

P25FD Turbocharger/Supercharger Bypass Valve C Temperature Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

This code says bypass valve C has become too hot. Recirculation valves are placed in the charge air path close to the compressor and thus near the hot turbine side, and an electric valve's coil adds its own heat when energised for long periods. How the engine module learns the temperature – a sensor in the valve or an estimate from current and duty cycle – is not stated in any public manufacturer document, and none documents P25FD itself. To protect the coil the module will usually limit or stop driving the valve, which can then lead to surging on lift-off or reduced boost. Separate codes cover the same overheating for valves A and B (P00D7, P00D8); a valve that is jammed rather than overheated is P25FC.

Likely causes

Heat soak from the turbocharger, e.g. after hard driving or with missing heat shields
Valve coil drawing too much current due to an internal fault
Sluggish valve held energised longer than intended

Symptoms

  • Check engine lamp on
  • Fluttering on lift-off or reduced boost after hard driving

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

bypass valve cbypass solenoid

Related codes

P25FCP25F8P00D7P00D8P2BC0

References: law.cornell.edu, ms-motorservice.com, en.wikipedia.org.