Code result
P2508
ECM/PCM Power Input Signal High
Moderate severity
What it means
The ECM/PCM switched-battery input reads above the upper threshold. Most often caused by a charging system overvoltage (failed alternator regulator) or wrong jump-start procedure. Sustained high voltage risks damaging ECU electronics.
Is it safe to drive?
Use caution
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
Alternator regulator overvoltage
highOne of the most commonly reported causes for this code — check this first.
Improper external power source or jump-start
mediumA plausible cause — test and verify before replacing parts.
Related help
Get the full diagnosis
Add your vehicle and see step-by-step repair help, recalls, and TSBs in Wrenchify.
Diagnose P2508 freeNo credit card required