Powertrain, generic (extended)

P2531 Ignition Switch Run Position Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

The engine module logs P2531 if the run-position input stays low although the vehicle state says the ignition is on, for example while the engine runs or the network reports run. The supply side is the usual suspect: an open fuse, a relay that does not pull in, a wire grounded on the body or a switch contact that no longer carries current. The module then behaves as if the key were turned off and may start shutting down. Ford's 2014 BOSS 302S code table is the one public manufacturer listing; there P2531 carries the M marker, so Ford lights the MIL for it, unlike the neutral P2530 and the high-side P2532. No thresholds are published. Drivers may face a stall, a restart problem or several warning lamps at once.

Likely causes

Open fuse in the run circuit
Run signal wire shorted to ground
Run relay not closing

Symptoms

  • MIL on
  • Engine stalls or will not restart
  • Several warning lamps or communication codes at once

Repair estimate

DifficultyMediumDIY possible
Parts and labour€10–400
Time0.5–3 h

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

Parts involved

ignition switchwiring harness

Related codes

P2530P2532P2534

References: performanceparts.ford.com, law.cornell.edu.