Ford Mustang (1999-2004) Service Manual: Inspection and Verification

NOTE: Upon installation of a new GEM, the module must be reconfigured. For additional information, refer to Section.

1. The warning lamps are a GEM controlled system; refer to Section.

2. Verify the customer concern by operating the system in question.

3. Visually inspect for the following obvious signs of mechanical and electrical damage.

Visual Inspection Chart

Mechanical Electrical

  • Switch(es)
  • Central junction box (CJB) fuses:
  • 28 (15A)
  • 32 (15A)
  • 39 (5A)
  • Circuitry

4. If the concern remains after the inspection, connect the diagnostic tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:

  • check that the program card is correctly installed.
  • check the connections to the vehicle.
  • check the ignition switch position.

5. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool manual.

6. Carry out the Data Link Diagnostic Test. If the diagnostic tool responds with:

  • CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Section.
  • NO RESP/NOT EQUIP for GEM, go to Pinpoint Test A.
  • NO RESP/NOT EQUIP for RCM, refer to Section.
  • SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM.

7. If the DTCs retrieved are related to the concern, go to the GEM Diagnostic Trouble Code (DTC) Index to continue diagnostics.

8. If no DTCs related to the concern are retrieved, proceed to the Symptom Chart to continue diagnostics.

9. If the DTCs retrieved are for the RCM, refer to Section.

GEM Diagnostic Trouble Code (DTC) Index

DTC Description Source Action
B1340 Chime Input Request Circuit Short to Ground GEM Go To Pinpoint Test C .
B1342 ECU Is Defective GEM CLEAR the DTCs. TEST the system for normal operation.

RETRIEVE the DTCs. If DTC B1342 is retrieved, INSTALL a new GEM.
B1353 Ignition Key-In Circuit Open GEM Go To Pinpoint Test B .
B1462 Safety Belt Switch Circuit Failure GEM Go To Pinpoint Test F .

Symptom Chart

Condition Possible Sources Action
  • No communication with the generic electronic module (GEM)
  • Central junction box (CJB) fuses:
  • 39 (5A).
  • 32 (15A).
  • Circuitry.
  • Generic electronic module (GEM).
  • Go To Pinpoint Test A .
  • The key-in-ignition chime does not operate correctly
  • Central junction box (CJB) fuses:
  • 28 (15A).
  • 32 (15A).
  • Central junction box (CJB).
  • Driver door ajar switch.
  • Key-in ignition switch.
  • Circuitry.
  • Generic electronic module (GEM).
  • Ignition switch.
  • Go To Pinpoint Test B .
  • A chime does not operate correctly-air bag
  • Restraint control module (RCM).
  • Circuitry.
  • Generic electronic module (GEM).
  • Ignition switch.
  • Go To Pinpoint Test C .
  • The door ajar chime does not operate correctly
  • Driver door ajar switch.
  • Passenger door ajar switch.
  • Circuitry.
  • Generic electronic module (GEM).
  • Ignition switch.
  • Go To Pinpoint Test D .
  • The headlamp on reminder chime does not operate correctly
  • Headlamp switch .
  • Circuitry.
  • Generic electronic module (GEM).
  • Driver door ajar switch.
  • Ignition switch.
  • Go To Pinpoint Test E .
  • The safety belt warning chime does not operate correctly
  • Circuitry.
  • Safety belt switch.
  • Generic electronic module (GEM).
  • Ignition switch.
  • Go To Pinpoint Test F .
  • The belt minder feature does not operate correctly
  • Circuitry.
  • Safety belt switch.
  • Generic electronic module (GEM).
  • Ignition switch.
  • Go To Pinpoint Test F .
    Principles of Operation
    Key-In-Ignition Warning Chime The key-in-ignition warning chime activates when the generic electronic module (GEM) detects the ignition switch circuits are in the OFF or ACC states and when the ...

    Pinpoint Tests
    CAUTION: Before removing and installing the generic electronic module (GEM) or its connectors, disconnect the battery. Failure to follow this caution will result in the GEM storing many erro ...

    Other materials:

    Exterior mirrors
    Power Exterior Mirrors WARNING: Do not adjust the mirror while your vehicle is in motion. A. Left mirror B. Off C. Right mirror To adjust your mirrors: 1. Select the mirror you want to adjust. 2. Move the control in the direction you want to tilt the mirror. ...

    Inspection and Verification
    1. Verify the customer's concern by operating the climate control system to duplicate the condition. 2. Inspect to determine if one of the following mechanical or electrical concerns apply: Visual Inspection Chart Mechanical Electrical ...

    Dual-Function Pressure Switch (4.6L)
    The dual-function pressure switch is used to interrupt A/C compressor operation in the event of high system discharge pressures. The dual-function pressure switch is mounted on a Schrader valve-type fitting on the high pressure side of the A/C manifold ...