Powertrain, generic (extended)

P25F1 Vacuum Pump Control Circuit B High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P25F1 marks a high reading on the vacuum pump's second (B) control circuit: the module sees voltage on the switched side when it should be low, for example because the line is shorted to battery voltage, the relay contacts have welded together or the pump has lost its ground. In the welded-relay case the pump keeps running after it has been switched off, which wears it out and drains the battery. No manufacturer documents P25F1 publicly. Ford's hybrid summary checks the comparable circuit A against a 1.3 to 5.0 V window with the relay open, a pattern that would also catch a supply that is stuck on. CARB 13 CCR 1968.2 requires electrical outputs to be checked for circuit faults. The opposite fault is P25F0, and P25EE is the open circuit. Drivers may hear the pump running constantly.

Likely causes

Pump relay contacts welded closed
Feedback or supply line shorted to battery voltage
Lost ground connection at the pump

Symptoms

  • Vacuum pump running constantly, even with the vehicle switched off
  • Discharged 12 V battery
  • Warning lamp on

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–600
Time0.3–2.5 h

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

Parts involved

vacuum pumppump relaywiring harness

Related codes

P25EEP25EFP25F0P258D

References: fordservicecontent.com, law.cornell.edu.