CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Caterpillar


Transmission, SPN 3823 - FMI 4

Usage:

CX28 TBB
Conditions Which Generate This Code:


Illustration 1g01245812

Schematic of the torque converter oil temperature sensor

This diagnostic trouble code is associated with the torque converter oil temperature sensor. The FMI 4 means that the ECU has determined that the voltage of the circuit for the position sensor is below normal.

The possible causes of this diagnostic trouble code are listed below:

  • The signal circuit for the sensor is shorted to ground.

  • The sensor has failed.

  • The ECU has failed. The ECU failing is unlikely.

Note: The following test procedure may create other diagnostic trouble codes. Ignore these created diagnostic trouble codes and clear the diagnostic trouble codes when the original diagnostic trouble code has been corrected. Ensure that the diagnostic trouble code of SPN 3823 FMI 4 is active before performing this procedure.

Note: Use a digital multimeter for the measurements in this procedure.

Test Step 1. CHECK THE SENSOR

  1. Turn the disconnect switch and the key start switch to the ON position.

  1. Ensure that the diagnostic trouble code is active.

  1. Observe the status of the diagnostic trouble code. Disconnect the sensor from the machine harness.

Expected Result:

The SPN 3823 FMI 4 remains active. The FMI has not changed and the "04" is still active.

Results:

  • OK - The diagnostic trouble code remains active. The sensor is correct. Proceed to Test Step 2.

  • NOT OK - The diagnostic trouble code is no longer active. The sensor has failed.

    Repair: Replace the sensor.

    STOP

Test Step 2. CHECK THE WIRING HARNESS OF THE SENSOR FOR A SHORT TO GROUND.

  1. Turn the key start switch and the disconnect switch to the OFF position.

  1. Disconnect the machine harness from the sensor.

  1. Disconnect the machine harness connectors from the ECU.

  1. At the machine harness connector for the ECU, measure the resistance from the signal contact J1-29 (wire 407-PK) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors for the ECU.

Expected Result:

Each resistance measurement is greater than 5000 ohms.

Results:

  • OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.

  • NOT OK - One or more resistance measurements is not correct. There is a short in the machine harness.

    Repair: The short is between signal contact J1-29 (wire 407-PK) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.

    STOP

Test Step 3. CHECK IF THE DIAGNOSTIC TROUBLE CODE IS STILL ACTIVE.

  1. Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.

  1. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.

  1. Reconnect all harness connectors in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are fastened.

  1. Turn the disconnect switch and the key start switch to the ON position.

  1. Operate the machine.

  1. Determine if the SPN 3823 FMI 4 is active.

Expected Result:

The SPN 3823 FMI 4 is active.

Results:

  • YES - The SPN 3823 FMI 4 is active. The problem has not been corrected.

    Repair: Check the circuit again. If the Caterpillar Electronic Technician (ET) is available, use the Cat ET service tool in order to perform a "Wiggle Test" on the machine wiring harness. The "Wiggle Test" can detect shorts and opens in the machine wiring harness that are momentary or intermittent. It is unlikely that the ECU has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic trouble code is not found, replace the ECU. Prior to replacing an ECU, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Unit - Replace".

    STOP

  • NO - The SPN 3823 FMI 4 is not active. The problem does not exist at this time. The initial diagnostic trouble code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.STOP

Caterpillar Information System:

CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3823 - FMI 3
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3823 - FMI 16
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3509 - FMI 4
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3509 - FMI 3
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3463 - FMI 2
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3027 - FMI 4
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3027 - FMI 3
Reuse and Salvage of Transmission Components {3030} Reuse and Salvage of Transmission Components {3030}
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 191 - FMI 8
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 191 - FMI 14
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 190 - FMI 8
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 177 - FMI 4
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission Shifting Function
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System System Protection Functions
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Additional Functions
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 3825 - FMI 8
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 513 - FMI 19
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Programmable Parameters
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 513 - FMI 9
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 525 - FMI 9
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission Control
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 639 - FMI 14
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 639 - FMI 9
CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Transmission, SPN 734 - FMI 3
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.