259D Compact Track Loader – MID 039 – CID 2477 – FMI 08

Conditions Which Generate This Code:

Illustration 1g03372385

Schematic of the Right Joystick Position Sensor

This diagnostic is associated with the Left/Right Position Sensor of the Right Joystick base. The sensor provides an input signal to the ECM. The diagnostic code is recorded when the ECM has determined that the signal frequency or the signal pulse width is not within the expected range.

The sensor is a PWM sensor that operates at a frequency of 500 ± 80 Hz. The duty cycle of the signal will vary from approximately 20% at the joystick full rearward position to approximately 80% at the joystick full forward position. When the joystick is in the center position, the duty cycle will be approximately 50%.

The possible causes of this diagnostic code are listed below:

  • The sensor has failed.

  • Intermittent connections or poor connections

  • The ECM has failed. This is unlikely.

Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected. Verify that CID 2477 - FMI 08 is active before performing this procedure.


  1. Turn the key switch to the ON position.

  1. At the harness connector for the right joystick, insert 7X-1710 Multimeter Probes along the contact for the power supply 1 wire 127-ORand along ground contact 2 wire 203-BK. Do not disconnect the machine harness from the connector for the joystick.

  1. Measure the (12 VDC) battery voltage of the sensor power supply. The key start switch remains in the ON position.

Expected Result:

The (12 VDC) battery voltage measurement is available.


  • OK - The (12 VDC) battery measurement is correct. Proceed to Test Step 2.

  • NOT OK - The measurement is not correct.

    Repair: Repair or replace the harness.



  1. Disconnect the negative battery cable and turn the key start switch to the OFF position.

  1. Disconnect machine harness connectors J1 and J2 from the Machine ECM.

  1. At the J2 harness connector for the machine ECM, measure the resistance from the sensor signal contact J2-51 E850-BR). to all other J1 and J2 contacts that are used for the machine ECM.

Expected Result:

Each resistance measurement is greater than 5000 ohms.


  • OK - Each resistance measurement is greater than 5000 ohms. The signal circuit is not shorted. Proceed to Test Step 3.

  • NOT OK - A resistance measurement is less than 5000 ohms.

    Repair: There is a short in the machine harness. The short is between the signal circuit and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.



  1. Inspect the harness connectors and clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, corrosion, 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 making sure that the connectors are fully seated and the clips for each connector are completely fastened.

  1. Reconnect the negative battery cable and turn the key start switch to the ON position.

  1. Operate the machine.

  1. Check the status of the CID 2477 - FMI 08.

Expected Result:

The CID 2477 - FMI 08 is not active.


  • OK - The CID 2477 - FMI 08 is not active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor connection or a short at one of the connectors that was disconnected and reconnected. Resume normal operation. STOP

  • NOT OK - The CID 2477 - FMI 08 is active. The diagnostic code has not been corrected.

    Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace"


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