P0601: The engine computer has a memory error
Internal Control Module Memory Check Sum Error
The engine computer failed its own memory check. Get it checked as soon as you can. If the engine runs erratically or shifting seems wrong, do not drive it: have it towed.
Stop driving and get help if
- The check engine light is flashing
- The temperature gauge runs high, or you see steam (overheating)
- The car loses power, hesitates badly or stalls
- You smell burning or see smoke
- A brake warning light comes on, or the brakes feel different
Pull over as soon as you can, turn the engine off, and call a tow or roadside help.
What it means
P0601 means the PCM (engine computer) ran a self-check on its internal memory and found that the stored data does not match what it calculated, like a file that has been corrupted. The checksum is a verification number; if the data in memory was altered or lost, the checksum will not match and this code is stored. The computer may also have frozen or irrational stored calibrations. Causes range from a bad PCM to low voltage events like a dead battery that corrupted memory. Before condemning the PCM, verify the electrical system is healthy.
Common causes
- Faulty or corrupted PCM memoryThe memory chips inside the PCM have developed an error. May require PCM replacement or reflash.
- Voltage spike or battery event that corrupted PCM memoryJump-starting with reversed cables, a failed alternator, or a dead battery can damage PCM memory.
- PCM software corruptionOn some platforms, a reflash with updated software resolves the checksum error without hardware replacement.
What the fix could involve
From the cheaper fix to the bigger one. Prices depend on your car, your area and the shop, so ask for a written quote that names the part and the labor before you approve it.
- PCM reflash or reprogramming
- PCM replacement and programming
Symptoms
- Check engine light on
- Erratic engine operation or control
- Transmission shift problems
- Other codes stored alongside P0601
- Possible no-start or stall
What to do next
Have the battery and charging system verified before anything else. Bring the car to a dealership or a shop with factory programming capability. Some PCM failures can be resolved with a software reflash, which is far cheaper than replacement. Replacement PCMs must be programmed to the specific VIN and vehicle configuration.
Lewis saves every code it reads to your scan history, which helps a technician see whether P0601 stands alone or appeared with other electrical faults. Get Lewis on the App Store or Google Play.
Related codes
FAQ
- Does P0601 always mean I need a new computer?
- No. Some cases are resolved by a software reflash, especially if a manufacturer has issued a technical service bulletin for the issue. Check for TSBs on your model.
- Can jump-starting cause this?
- Yes. If a jump-start was done with reversed polarity or with a very powerful source, it can send a voltage spike that damages PCM memory.
- Can I drive to the dealer?
- If it is stalling, misfiring, or shifting erratically, have it towed to avoid further damage. Either way, get it to the dealer as soon as you can.
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