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P0604 Powertrain

Internal Control Module Random Access Memory (RAM) Error

ECU self-test detected a RAM fault during runtime checks. This is an internal ECU defect; replacement or reflash with manufacturer support is generally required.

Affected components

  • Ecm

Common causes

  • High likelihood: ECU internal RAM fault
  • Low likelihood: Module software outdated, reflash may resolve
  • Low likelihood: Supply voltage outside specification

Possible symptoms

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

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • Reduced-power or limp mode may occur

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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