P2505
ECM/PCM Power Input Signal
What it means
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.
Is it safe to drive?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Failed main relay
highOne of the most commonly reported causes for this code — check this first.
Blown fuse on the ECM power feed
mediumA plausible cause — test and verify before replacing parts.
Corroded connector pin at the ECM
mediumA plausible cause — test and verify before replacing parts.
Related help
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