510
Thermo King
Critical

ECU Run Signal Failed

The controller sent the run signal but the ECU did not respond or confirm the running status.

Possible causes

  • Run signal wiring failure
  • Internal engine ECU problem
  • Defective crankshaft position sensors
  • Lack of fuel or air in the intake

Recommended actions

  • Test continuity of the run signal circuit
  • Check specific fault codes within the engine ECU
  • Review fuel delivery system
  • Replace run relay if damaged

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