Internal Control Module KAM Error
What does P0603 mean?
The P0603 code means the vehicle's onboard diagnostic system has detected: Internal Control Module KAM Error. This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated
- Adaptive memory reset -- idle may fluctuate
- Radio presets and clock may reset
- Fuel trims return to default values
Probable Causes (Ranked by Likelihood)
- Battery disconnected or dead causing KAM loss Very High
- Loose or corroded battery cable High
- Failed KAM power supply circuit in ECM Moderate
- Parasitic draw draining the battery Low
Step-by-Step Diagnostic Procedure
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Check battery condition and terminal connections -- clean and tighten as needed
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Measure battery voltage with engine off -- should be above 12.4V
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Check for parasitic electrical draw that may drain the battery
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Clear the code and drive the vehicle through a complete drive cycle to relearn adaptive values
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If the code returns with a good battery, the ECM KAM circuit may be faulty
Frequently Asked Questions
Can I drive with code P0603?
Yes, you can drive. Internal control module errors can cause unpredictable engine behavior.
Does P0603 mean I need a new ECM?
Not always. Some internal module errors can be resolved by reprogramming or reflashing the ECM with factory software. However, hardware failures (RAM, ROM, processor) typically require ECM replacement.
How much does an ECM replacement cost?
ECM replacement typically costs $300-$1500 including the part and programming. The ECM must be programmed with the correct calibration and vehicle options for your specific VIN.