P0603 - Internal Control Module Keep Alive Memory (KAM) Error
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Internal Control Module Keep Alive Memory (KAM) Error (P0603). The underlying code points specifically at non-volatile memory (EEPROM/KAM).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Internal Control Module Keep Alive Memory (KAM) Error – Permanent B+ Supply | Voltage (V) | 12.4 - 12.7 V (ignition OFF) / 13.5 - 14.7 V (engine running) | At module supply pins |
| Internal Control Module Keep Alive Memory (KAM) Error – Ignition-Switched Supply | Voltage (V) | 11.8 - 14.4 V | Ignition ON |
| Internal Control Module Keep Alive Memory (KAM) Error – Ground Connections Voltage Drop | Voltage (V) | < 0.1 V per ground point | Under load to battery negative |
| Internal Control Module Keep Alive Memory (KAM) Error – 5 V Reference Outputs | Voltage (V) | 4.95 - 5.05 V per circuit | Ignition ON, sensors unplugged one at a time |
At module supply pins
Ignition ON
Under load to battery negative
Ignition ON, sensors unplugged one at a time
Oscilloscope Waveform Analysis
500 ms/div, 5 V/divPossible Causes
Lost adaptation values after a battery disconnect, or a worn EEPROM cell after many write cycles
Short to ground on the signal wire or an internal short circuit within Internal Control Module Keep Alive Memory (KAM) Error
Chafed or pinched wiring harness along the signal path to Internal Control Module Keep Alive Memory (KAM) Error
Poor ground connection or excessive voltage drop (> 0.1 V) at the ground point for Internal Control Module Keep Alive Memory (KAM) Error
Defective internal output driver or reference circuit in the control module for Internal Control Module Keep Alive Memory (KAM) Error
Symptoms
4
Recommended Solution
Re-run all basic settings and adaptations (throttle, transmission, steering) with the scan tool; verify they persist after an ignition cycle.
Check wire insulation resistance to ground (< 1 Ω indicates harness pinched or chafed against engine block/chassis).
Verify loaded supply voltage and harness terminal pins at Internal Control Module Keep Alive Memory (KAM) Error.
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Internal Control Module Keep Alive Memory (KAM) Error.
Inspect module enclosure and connector headers for water ingress, fretting corrosion, or PCB thermal damage.
Mechanic's Tip
If adaptations do not survive an ignition cycle the EEPROM cell is worn out — only module repair or replacement helps.