Internal Control Module Read Only Memory (ROM) Error
ECU self-test detected a ROM/checksum failure on the program memory. The control software cannot be trusted; vehicle typically defaults to limp-home with reduced function.
Affected components
- Ecm
Common causes
- High likelihood: ECU internal ROM fault
- Low likelihood: Module software outdated, reflash may resolve
- Low likelihood: Supply voltage outside specification
Possible symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Diagnostic notes
- The malfunction indicator lamp may illuminate
- Reduced-power or limp mode may occur
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.