P0601 Internal Control Module Memory Check Sum Error
P0601 is a generic OBD2 powertrain diagnostic trouble code for internal control module memory check sum error. The code identifies the system or circuit the engine computer flagged, but diagnosis still depends on vehicle symptoms, freeze-frame data, and related codes.
Voltage, module, and sensor-reference codes can create many false symptoms. Fix power and ground problems before chasing individual sensors.
Common symptoms
- Check engine light
- No-start or stall
- Multiple unrelated codes
- Battery light
- Intermittent drivability problems
Likely causes
- Weak battery
- Charging-system fault
- Bad ground
- Sensor reference short
- Module power relay or wiring issue
What to check before replacing parts
Test battery and charging voltage
Check main grounds
Inspect fuses and relays
Look for shared 5V reference faults
Clear and rescan after voltage repair
A code points at the system, not always the failed part. Add your vehicle, mileage, symptoms, and whether the check engine light is steady or flashing so the AI diagnostic can narrow the next step.