P0603: Internal Control Module Keep Alive Memory (KAM) Error
The ECU detected a fault in its KAM (battery-backed memory used to store adaptations and DTCs). Often appears after battery disconnect or low battery; persistent codes indicate an internal ECU fault.
What P0603 means
P0603 is a generic OBD-II powertrain code in the computer & electrical group.
- Check engine light
- Usually on
- Emissions-related
- No
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
Post this code once and get quotes from local mechanics. Free to post.
Makes the repair and parts links below specific to your car. Kept in this browser only.
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Common causes
- 01Battery disconnected or voltage too lowMost likely
- 02ECU internal memory faultLess likely
- 03Module software outdated, reflash may resolveLess likely
Can I drive with P0603?
Usually yes, for a short time.
The car will often drive normally, but get it diagnosed soon. If you notice rough running, warning lights flashing, overheating or a burning smell, stop driving.
Why we rate it moderate
- Turns on the check engine light
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P0603
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P0603. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Fix other faults first
If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.
- 3
Check live data
Watch the related sensor and actuator readings in live data (ECM, Vehicle battery) and compare them with expected values in the service information for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Battery disconnected or voltage too low; ECU internal memory fault; module software outdated, reflash may resolve. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
P0603 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Easy
- Good DIY job?
- Yes, with a scan tool
Basic hand tools; a common first DIY job.
Parts and systems involved
- ECM
- Vehicle battery
P0603 FAQ
What does P0603 mean?
P0603 means “Internal Control Module Keep Alive Memory (KAM) Error”. The ECU detected a fault in its KAM (battery-backed memory used to store adaptations and DTCs). Often appears after battery disconnect or low battery; persistent codes indicate an internal ECU fault.
Is P0603 serious? Can I keep driving?
We rate P0603 as moderate severity. Usually yes, for a short time. The car will often drive normally, but get it diagnosed soon. If you notice rough running, warning lights flashing, overheating or a burning smell, stop driving.
What causes P0603?
The most common causes, from most to least likely: Battery disconnected or voltage too low; ECU internal memory fault; Module software outdated, reflash may resolve. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P0603?
Typical labor is about $15–$500 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P0603 myself?
DIY difficulty is easy. Many owners can handle it with a scan tool, a multimeter and basic hand tools. Always confirm the cause before buying parts.
Will P0603 clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.