ECM/PCM Power Input Signal
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.
Affected components
- Main relay
- Power input wire
- Ecm
Common causes
- High likelihood: Failed main relay
- Medium likelihood: Blown fuse on the ECM power feed
- Medium likelihood: Corroded connector pin at the ECM
Diagnostic notes
- The malfunction indicator lamp may illuminate
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.