P0601: Internal Control Module Memory Checksum Error
What to do
May be driveable, may not. This is a fault inside the control module rather than in a sensor or actuator, so it needs a franchised dealer or a specialist with manufacturer programming tools — there is no part to swap and general-purpose scan tools cannot repair it. If it appeared immediately after a battery change, a jump start, or software work, say so: that is very likely the cause and it affects how it is approached.
What this code means
The module's stored program failed its own integrity check. A checksum is a value calculated across the whole of the stored software and compared against a recorded figure — when they disagree, the module knows its own contents have changed and refuses to trust them.
The honest thing to say about this code is that it is not usually repairable by replacing a part. Either the memory has genuinely degraded, or the stored program was corrupted — and corruption most often happens during a failed software update, or when battery voltage collapses while a module is writing to memory.
That second cause is worth stating plainly because it is preventable: jump-starting badly, or a battery disconnected mid-update, can corrupt a module that was perfectly healthy. It is also why any workshop reprogramming a module puts a stabilised supply on the battery first.
Likely causes
Start here
- Corrupted module software · specialist
- Failed software update · specialist
- Voltage collapse during memory write · specialist
Less common
- Degraded module memory · specialist
- Failing battery · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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