P0603Internal Control Module Keep Alive Memory (KAM) Error
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Keep alive memory holds learned values – fuel trim, idle and shift adaptation, readiness status – while the engine is off, as long as the module has constant battery power; CARB defines it as memory that is lost when the battery or fuse is disconnected. The module stores a checksum of this memory at shutdown and compares it at the next start (Ford, GM Europe); GM calls the check 'long term memory reset', and the Ford diesel watches the supply of its engine-off timer chip (below 0.25 V). By far the most common trigger is outside the module: a disconnected, flat or replaced battery or an interrupted constant feed – Nissan bulletins name exactly this and ask for at least 11 V before clearing. Learned values then start from default and the readiness monitors are reset. Whether the lamp comes on depends on the maker.
- What you may notice
- Check engine light on (depending on the maker)
- Rough idle or changed shifting until values are relearned
- Readiness monitors reset
- Often right after battery work
- Likely causes
- LikelyBattery disconnected, deeply discharged or replaced
- PossibleInterrupted constant power feed to the module (fuse, wire, corrosion)
- RareMain relay drops out too early, memory not saved completely at shutdown
- RareInternal memory defect (EEPROM/NVM)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €0 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.