P0603 — Control module keep-alive memory (KAM) error

P0603: Control module keep-alive memory (KAM) error — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

The fault concerns keep-alive memory, used to retain operating data between powered operating periods. It is not the same as a RAM or ROM code. The retention and supply arrangements depend on the controller, so a battery fault must not be assumed from the DTC alone.

Affected system: Control module self-diagnostics

Symptoms

  • Difficult starting; uneven running and reduced power.

Possible causes

  • Unstable supply, poor grounds or corroded module connections.

What to check

  • Check retained supply, connectors and grounds before evaluating the module.

Also written as: P0603-00, P060300, PO603 (some scan tools add the fault-type byte, e.g. -00).