F4

UnclassifiedCooling

What This Code Means

Engine shut-down; Coolant temperature fault indicator lights up; Engine shutdown; Engine oil pressure fault indicator lights up; Spare shutdown indicator lights up; Fuse (F4) activates; Alternator charging indicator (L3) does not go out after starting; Failing alternator; AC shutdown indicator (L4) lights up; Overspeed shutdown indicator (L5) lights up; Engine coolant temperature fault indicator (L6) lights up; Engine oil pressure fault indicator (L7) lights up

Possible Causes

  • Engine oil pressure drops to 7.25 psi (0.5 bar)
  • Engine coolant temperature reaches 221 °F (105 °C)
  • High engine coolant temperature
  • Low engine oil pressure
  • Low fuel level
  • Current from the battery to the engine control circuit exceeds its setting
  • Alternator is failing
  • No AC input is present
  • Engine speed has exceeded 115 % of the nominal speed

ASK RUDY ABOUT THIS FAULT

Get a diagnosis walkthrough for F4 on your specific Atlas Copco unit — cited to the OEM manual, not a forum guess.

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