Powertrain, generic (extended)

P2505 ECM/PCM Power Input Signal

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2505 covers the supply inputs of the engine module in general. GM documents it in the 2014 diesel engine table 14OBDG04: the module checks its permanent battery feed, the line that keeps the engine-off timer alive while the ignition is off. If that constant supply was interrupted, the module flags P2505 as soon as the ignition is on; a single event is enough, the test is evaluated a single time per trip and the code is GM type B, so the MIL follows on the second failing trip. Without that feed the module cannot know how long the engine was off, which other diagnostics rely on. Ford lists P2505 without MIL marker for the 2014 BOSS 302S. P2506 to P2509 narrow the fault to plausibility, low, high and intermittent.

Likely causes

Battery disconnected or permanent-feed fuse removed or blown
Open or corroded permanent supply wire or connector
Supply monitoring inside the module defective

Symptoms

  • MIL after two trips (GM)
  • Often no drivability complaint
  • Learned values may be lost

Repair estimate

DifficultyMediumDIY possible
Parts and labour€10–400
Time0.3–2 h

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

Parts involved

main relaypower input wireecm

Related codes

P2506P2507P2508P2509P0560

References: gsi.ext.gm.com, performanceparts.ford.com, law.cornell.edu.