P0601 code meaning
Internal Control Module Memory Checksum Error
Powertrain system Generic code P06xx codes Check engine light
What P0601 means
The module continuously calculates a checksum over its program and calibration memory (flash) and compares it with the stored value; on newer units the flash error correction also reports bit errors it cannot repair. A mismatch means the stored software is corrupted. GM sets P0601 in the engine module after one failed pass (or five once the first pass is complete) and turns on the lamp in the first trip; in body modules after two trips. Ford reports the same check as P0605, while GM, VW and Mazda use P0601. Typical causes are an interrupted reflash and manufacturer software errors – VW (2.0 TFSI) and Mazda (MX-5 2013) fixed it by reprogramming. The code alone does not say which module set it – the scan tool shows whether it is the engine, transmission, brake or body module.
P0601 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0601
- Check engine light on
- Often no change in driving
- Possibly no start or limp mode if the software is badly damaged
- Transmission limp mode if the transmission module is affected
Common causes of P0601
- Most likelyInterrupted or faulty reprogramming
- PossibleFaulty module software (update available)
- PossibleDefective flash memory in the module
- Less likelyLow voltage, voltage dips or a poor ground or supply at the module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Engine control moduleControl module power supplyControl module ground
What each part of P0601 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 6 | Area: computer (engine control module) and output circuits. |
| 01 | The exact fault in that area. |
What to do next
- Note P0601 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0601
What does P0601 mean?
P0601 means "Internal Control Module Memory Checksum Error". The module continuously calculates a checksum over its program and calibration memory (flash) and compares it with the stored value; on newer units the flash error correction also reports bit errors it cannot repair. It is a generic code, so it means the same on every make.
Is it safe to drive with P0601?
Drive gently and only to a workshop. With P0601 the car can go into limp mode (reduced power) to protect itself.
Will P0601 fail an emissions test?
Yes, it can. P0601 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0601 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0601 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.