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ElectricalSeverity Medium: diagnose soon

P0603Internal Control Module Keep Alive Memory (KAM) Error

What it means

The ECU lost the memory it keeps with the ignition off (adaptations, codes). Often caused by a disconnected battery or a supply fault, less often by the ECU.

Symptoms

  • Check engine light
  • Possibly no start, stalling or limp mode
  • Other codes may be stored at the same time

Common causes

  • Low voltage or poor ground at the ECU
  • Water ingress or corrosion in the ECU or its connector
  • Software problem (update may exist)
  • Internal ECU fault

What to check first

  1. Check ECU power and ground supplies under load
  2. Check the ECU and connectors for water or corrosion
  3. Look for a software update or technical bulletin before replacing the ECU
Can I drive with P0603? Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0603: questions and answers

What does P0603 mean?

P0603: Internal Control Module Keep Alive Memory (KAM) Error. The ECU lost the memory it keeps with the ignition off (adaptations, codes). Often caused by a disconnected battery or a supply fault, less often by the ECU.

What are the symptoms of P0603?

Check engine light. Possibly no start, stalling or limp mode. Other codes may be stored at the same time.

What causes P0603?

Low voltage or poor ground at the ECU. Water ingress or corrosion in the ECU or its connector. Software problem (update may exist). Internal ECU fault.

How do you diagnose P0603?

1. Check ECU power and ground supplies under load 2. Check the ECU and connectors for water or corrosion 3. Look for a software update or technical bulletin before replacing the ECU

Can I drive with P0603?

Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.