OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

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.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number6 / 03

Possible causes

  • Battery disconnected or voltage too low high
  • ECU internal memory fault low
  • Module software outdated, reflash may resolve low

Symptoms

  • Check engine light on
  • Possible limp mode or no-start
  • Multiple follow-up faults across modules
  • Reset/relearn may be needed after repair

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 80–800 €
  • Estimated time: 0.1–4 h
  • Component: ecm
  • Component: vehicle battery
  • MIL / check engine light

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication