P2505

  • Powertrain
  • Manufacturer-specific
SeveritySeverity level 3 of 5: Diagnose soon.

Diagnose soon

Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.

Standard definition

ECM/PCM Power Input Signal

This code is in our catalogue but has not yet been through editorial review, so the guidance below is limited to what our structured data supports. We publish deeper diagnostic content only after a code has been reviewed — here is why.

In plain English

The ECM/PCM monitors the main switched battery feed (typically terminal 15 / ignition-switched supply via the main relay). A general fault is reported — either the input is missing entirely or it does not match the expected timing relative to ignition state. Engine may not start or stay running.

A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.

Can I keep driving?
Safe to drive
Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.
Urgency
Diagnose soon
Will it pass emissions
Not affected
Check engine light
Solid
Likely causes
#CauseHow oftenComponent
1Failed main relayVery common
2Blown fuse on the ECM power feedCommon
3Corroded connector pin at the ECMCommon

Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.

Components involved
  • Main Relay
  • Power Input Wire
  • ECM
Sources
Definition
Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.
Diagnostic guidance
Written and reviewed in-house. See our editorial policy.
Review status
Awaiting review

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