OBD-II · Engine and powertrain (P)
P0603
Internal control module keep-alive memory (KAM) error
What it means
The ECU's memory that holds learned values did not survive the last switch-off, often after the battery was disconnected or went flat.
Symptoms
- engine warning light
- possible limp mode, stalling or no start
- sometimes no noticeable change
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | battery disconnected or run flat |
| 02 | poor ECU permanent power feed or earth |
| 03 | blown fuse for the ECU permanent supply |
| 04 | internal ECU fault |
What to check, step by step
- 01Check whether the battery was recently disconnected or flat: the code may clear itself once and not return
- 02Check the battery and the ECU's permanent power supply fuse and earths
- 03Clear the code and see whether it returns after several drive cycles
- 04Replace or repair the ECU only if the supply is good and the code keeps returning