Parts
$200–1200
P0601 — Internal Control Module Memory Check Sum Error
CAUTIONIs it safe to drive? The ECM failed its own internal memory self-test — this is a serious ECM fault; get it to a shop with factory scan equipment before trusting the vehicle on long trips.
What P0601 means
When the ECM powers up, it runs a checksum test on its own internal memory. P0601 means the calculated checksum didn't match the stored value — indicating corrupted program memory, a failed memory chip, or (rarely) a voltage spike that scrambled data. Not a sensor or wiring code.
Most likely causes (in order)
- ECM memory corrupted from a voltage spike (load dump, jump-start surge)
- Internal memory chip failed (age or heat)
- Battery disconnected while ECM was writing data
- Aftermarket tune or module flash went wrong
- ECM failed from moisture, heat, or vibration damage
Symptoms you might notice
- CEL on
- multiple stored codes across systems
- engine may run poorly or not start
- transmission stuck in failsafe
What to check first
Check battery terminals and ground connections first — a weak ground causes voltage spikes that corrupt ECM memory, and tightening a corroded ground sometimes resolves it. If the code returns after a battery reset, the ECM likely needs replacement or remanufacturing.
Repair cost & difficulty
Labor
1–3 hr
Difficulty
Advanced