What P0603 means
Internal Control Module Keep Alive Memory (KAM) Error
How to diagnose
- Read freeze frame data. When P0603 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P0603 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P0603 for slightly different failure modes:
| AUDI | Lack of proper voltage to the Keep Alive Memory connection on the PCM, Defective PCM Keep Alive Memory Module (KAM), Defective PCM ground circuit(s), Defective PCM controlled output devices |
| BMW | Internal Control Module Keep Alive Memory (KAM) Error |
| FIAT | Fault redundant memory EEPROM, |
| FORD | Powertrain Control Module KAM Test Error |
| HONDA | ECM/PCM Internal Control Module Keep Alive Memory (KAM) Error |
| MITSUBISHI | Internal Control Module Keep Alive Memory (KAM) Error; EEPROM fail |
| NISSAN | Internal Control Module Keep Alive Memory (KAM) Error |
| VOLKSWAGEN | Control Module Long Term Memory Reset |
Read P0603 on your own car
DIY Fix My Car reads P0603 plus 25,000+ other DTC codes with manufacturer-specific descriptions. Includes freeze frame data, likely fix parts, and AI mechanic chat. Download free.