Internal Control Module Memory Check Sum Error
The ECU's internal memory checksum does not match the expected value at startup — the firmware/calibration in flash has become corrupt. Often appears after a failed flash, low battery during programming, or genuine module hardware failure.
Affected components
- Ecm
Common causes
- Medium likelihood: Failed flash / interrupted programming
- Medium likelihood: Module hardware failure
- Low likelihood: Module software outdated, reflash may resolve
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.