ECM/PCM Power Input Signal High
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.
Affected components
- Alternator regulator
- Power distribution
Common causes
- High likelihood: Alternator regulator overvoltage
- Medium likelihood: Improper external power source or jump-start
Diagnostic notes
- The malfunction indicator lamp may illuminate
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.