P0601 Code: Control Module Memory — Causes & Fix
P0601 means the ECM/PCM has failed its internal memory (checksum) self-test — an internal fault in the control module.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $60 – $900
- Time to fix
- 30 minutes – 2 hours
What it means
Causes include an internal ECM fault, corrupted programming, or poor power/ground to the module. P0601 is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer petrol car or light truck regardless of make. Fix the underlying fault, then clear the code with an OBD-II scan tool — it will return if the problem isn't resolved.
Symptoms
- Check engine light on
- Poor running or no-start
- Other systems affected
How to fix it
- 1
Check module power and grounds
1. Inspect the ECM power and ground connections. 2. Confirm healthy battery/charging voltage.
- 2
Reflash or replace the ECM
1. If power/grounds are good, the ECM may need reprogramming or replacement. 2. Clear the code after repair.
Frequently asked questions
Does P0601 mean a new ECM?
Often, but not always — verify power and grounds first, and check whether a reflash resolves it before replacing the module.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.