P0603 Code: Control Module KAM Error — Causes & Fix
P0603 means the ECM/PCM keep-alive memory (KAM) has failed or been lost — the module's stored adaptive learning was corrupted or reset.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $40 – $600
- Time to fix
- 30 minutes – 2 hours
What it means
Causes include a weak/disconnected battery, poor ECM power/ground, or an internal module fault. P0603 is a generic OBD-II code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer OBD-II vehicle 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
- Rough running until relearned
- Reset adaptive settings
How to fix it
- 1
Check battery and ECM power
1. Test the battery and ECM power/ground connections. 2. Repair loose or corroded connections.
- 2
Reset/relearn
1. Clear the code and allow the ECM to relearn. 2. If it recurs, suspect an internal module fault.
Frequently asked questions
Can a weak battery cause P0603?
Yes — losing power to the ECM can wipe keep-alive memory. Check the battery and ECM power connections first.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.