P2509 – ECM/PCM Power Input Intermittent

Description

The ECM detects unstable or intermittent voltage at its power input.

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Symptoms

  • Flickering lights
  • Hesitation
  • Check engine light

Causes

  • Loose wiring
  • Failing alternator
  • Bad grounds

Diagnosis

  • Inspect wiring
  • Test alternator
  • Check grounds

Repair

  • Repair wiring
  • Replace alternator