2004 Ford Mustang Mach 1, AutomaticFACTORY OEM SERVICE PROCEDURE

Symptom Chart

SYMPTOM CHART

Condition Possible Sources Action
  • No communication with the generic electronic module (GEM)
  • Circuitry.
  • Central junction box (CJB) fuse 39 (5A).
  • GEM.
  • All door locks are inoperative
  • Central junction box (CJB) fuse 19 (15A).
  • Battery junction box (BJB) fuse POWER WINDOWS (40A).
  • Circuitry.
  • Generic electronic module (GEM)
  • Switches.
  • Lock actuators.
  • The doors do not lock/unlock using the remote transmitter
  • Remote transmitter.
  • Remote transmitter battery.
  • Remote transmitter programming.
  • Aftermarket system.
  • High power devices.
  • TV/radio transmission towers.
  • Generic electronic module (GEM).
  • The luggage compartment door is inoperative using the remote transmitter
  • Central junction box (CJB) fuse 25 (25A).
  • Remote transmitter battery.
  • Remote transmitter.
  • Generic electronic module (GEM)
  • Circuitry.
  • Luggage compartment lid release relay.
  • Panic feature is inoperative/does not operate correctly
  • Generic electronic module (GEM)
  • Driver door unlock relay.
  • Circuitry.
  • Remote transmitter and batteries.
  • Courtesy lamps.
  • Horn relay.
  • Horn.
  • Parklamps.
  • The remote keyless entry transmitter is out of synchronization
  • Remote transmitter.
  • Remote transmitter button pressed a substantial amount of times while outside the range of the vehicle.
  • Generic electronic module (GEM).
  • The remote transmitter has poor range performance
  • Aftermarket system.
  • High power devices.
  • TV/radio transmission towers.
  • Remote transmitter.
  • Generic electronic module (GEM).
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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