OBD-II code · Powertrain (generic)
P0601 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.
Is it safe to drive with P0601?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- PossibleFailed flash / interrupted programming
- PossibleModule hardware failure
- Less likelyModule software outdated, reflash may resolve
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–6 h
- Emissions test
- Usually unaffected
- Parts involved
- Ecm
Related codes
- P05FEActive Grille Air Shutter C Performance Stuck Off
- P05FFBrake Pressure Sensor and Brake Pedal Position Sensor Correlation
- P0600Serial Communication Link
- P0602Control Module Programming Error
- P0603Internal Control Module Keep Alive Memory (KAM) Error
- P0604Internal Control Module Random Access Memory (RAM) Error
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.