What does P0601 mean?

The engine control module detected an error in its own memory.

Does P0601 always require a new ECU?

Not always. A software reflash or a power/ground fix can solve some cases, but a failed module needs replacement.

Electrical and control module

P0601 — Internal Control Module Memory Check Sum Error

The engine control module found an error when checking its own memory. The ECU may behave unpredictably, so this fault should be taken seriously.

Severity: High

Common causes

Faulty engine control module (ECU/PCM)
Software or calibration corruption
Low battery voltage or voltage spikes during programming
Poor ground or power supply to the module
Water damage or corrosion inside the module

Symptoms

Hard starting or no start
Stalling and erratic running
Reduced power or limp mode
Check engine light

How to check

Check battery voltage, power and ground connections to the ECU
Check for related power-supply or communication codes
Clear the code and see whether it returns
Reflash/update the software or repair/replace the module if the fault persists

Can you keep driving?

Not recommended: the engine management may fail without warning. Have the module checked before driving.

P0602
P0603
P0606

Frequently asked questions

What does P0601 mean?: The engine control module detected an error in its own memory.
Does P0601 always require a new ECU?: Not always. A software reflash or a power/ground fix can solve some cases, but a failed module needs replacement.

General reference information. It does not replace a diagnosis on your own vehicle. The same code can have different causes depending on make, model year and engine; check the manufacturer's documentation or ask a technician with a scan tool.