Powertrain, generic (extended)

P258A Vacuum Pump Control Circuit A/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P258A stands for an open or otherwise faulty control circuit A of an electric vacuum pump, which supplies the brake booster on engines that provide too little manifold vacuum, such as hybrids, downsized turbo petrol engines and diesels. Ford's 2018-2019 hybrid OBD summary assigns it to the brake system module: with the pump relay commanded off, a monitoring line voltage outside 1.3-5.0 V for 100 ms sets the code (legacy brake code C1035). Stellantis case S2209000006 explains that the PCM can log P258A after a crank longer than 2.5 s because the pump is unpowered while cranking; in that case the code may simply be cleared, but a P258B alongside points to the pump itself. P258B to P258D cover performance, low and high faults, P25EE the open fault of circuit B. Braking assist can be reduced.

Likely causes

Faulty pump relay, blown fuse or poor relay contact
False entry after a long engine crank while the pump is unpowered
Open wire or loose connector between module, relay and pump
Failed electric vacuum pump

Symptoms

  • Engine or brake warning lamp on
  • Harder brake pedal at low speed or after several stops
  • Start-stop function disabled

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–700
Time0.3–2.5 h

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

Parts involved

vacuum pumpwiring harness

Related codes

P258BP258CP258DP25EEP050F

References: fordservicecontent.com, static.nhtsa.gov, law.cornell.edu.