P0601 Code: Internal Control Module Memory Check Sum Error
🟠 Moderate severity · drivable
Drivable, but the engine computer's memory has a fault, which usually requires reprogramming or replacement.
What P0601 means
The engine control module (PCM) has detected an error in its own internal memory — a checksum mismatch. This usually means the PCM's software is corrupted or the module is failing.
Symptoms
- Check engine light is on
- Possible running problems
- Multiple codes may appear
- Possible no-start
Common causes
- most common: Faulty engine control module (PCM)
- common: Low battery voltage corrupting memory
- less common: Failed software update
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Reprogram (reflash) the engine control module | Mechanic | $100–300 |
| Replace the engine control module | Mechanic | $500–1500 |
Frequently asked questions
Can I drive with a P0601 code?
Sometimes, but the PCM may fail. Get it reprogrammed or replaced soon.
What is the most common cause of P0601?
A faulty engine control module or corrupted software.
How much does it cost to fix a P0601?
Reprogramming is $100–$300; a replacement PCM is $500–$1,500.
Related codes
P0600
P0600 Code: Serial Communication Link Malfunction
P0606P0606 Code: ECM/PCM Processor Fault
P0602P0602 Code: Control Module Programming Error
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.