Internal Control Module Memory Check Sum Error
What does P0601 mean?
The P0601 code means the vehicle's onboard diagnostic system has detected: Internal Control Module Memory Check Sum Error. This is a critical severity code.
Common Symptoms
- Check Engine Light illuminated
- Engine may run rough or stall
- Multiple system malfunctions
- Vehicle may not start
- Erratic gauge behavior
Probable Causes (Ranked by Likelihood)
- Corrupted ECM/PCM internal memory Very High
- Failed ECM/PCM reprogramming attempt High
- Electrical spike or voltage surge damaging ECM memory Moderate
- Defective ECM/PCM hardware Moderate
Step-by-Step Diagnostic Procedure
-
Clear the code and recheck -- if it returns immediately, the ECM has a permanent fault
-
Check battery voltage and charging system -- low voltage can corrupt ECM memory
-
Verify ECM grounds are clean and tight
-
Attempt an ECM reflash or reprogramming with factory software
-
Replace the ECM/PCM if reflashing does not resolve the checksum error
Frequently Asked Questions
Can I drive with code P0601?
Drive short distances only. Internal control module errors can cause unpredictable engine behavior.
Does P0601 mean I need a new ECM?
Not always. Some internal module errors can be resolved by reprogramming or reflashing the ECM with factory software. However, hardware failures (RAM, ROM, processor) typically require ECM replacement.
How much does an ECM replacement cost?
ECM replacement typically costs $300-$1500 including the part and programming. The ECM must be programmed with the correct calibration and vehicle options for your specific VIN.