Internal Control Module Memory Check Sum Error
The engine computer checks on start-up that its internal program is intact by calculating a “checksum”. This code means that check has failed.
What the car has detected
On start-up, the engine computer's memory self-test did not give the expected result. The test runs even if the voltage is wrong, so low voltage can also cause it.
You may notice nothing, or the engine may run unevenly or fail to start. Get it checked soon and rule out a battery problem first.
Symptoms
- Engine warning light on
- Uneven running or hard starting in some cases
- Other voltage codes stored at the same time
Possible causes
- Low voltage during start-up (weak battery or poor earth points)
- Damaged engine computer memory, for example after an unofficial remap
- Failed engine computer
Checks for the garage
- Test the battery and charging system
- Check the engine computer's supply and earth points
- Clear the codes and see whether P0601 returns with correct voltage
- Check the software version and whether it has been modified
- Replace or reprogram the engine computer only as a last step
Next step
Have the battery, charging and earth points checked first, and whether the engine computer has modified or outdated software.
Go to a garage: checking and reprogramming the engine computer needs manufacturer equipment. This kind of internal fault usually can't be repaired, but often the real cause is voltage.