259D Compact Track Loader – MID 039 – CID 2795 – FMI 08

Conditions Which Generate This Code:

This diagnostic code is associated with the Accelerator Pedal position sensor circuit. The FMI 08 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range.

The Accelerator Pedal position control has an output frequency of approximately 500 Hz. The duty cycle of the signal changes as the Accelerator Pedal pedal position is changed. The duty cycle increases as the Accelerator Pedal pedal position is changed. Valid values range from 5% to 95% duty cycle.

The possible causes of this diagnostic code are listed:

• The Accelerator Pedal sensor has failed.

• Intermittent connections or poor connections

• Mechanical devices are loose.

• The ECM has failed. This is unlikely.

System Response:

The diagnostic code will generate a level 2 warning. Underspeed Control will be disabled and the hystat transmission will be limited to low speed.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 2795 FMI 08 is active before performing this procedure.

Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.

Test Step 1. CHECK FOR POWER AT THE SENSOR.

1. Do not disconnect the harness connector from the joystick.

2. Turn the key start switch to the ON position.

3. At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the voltage supply wire P769-YL (contact A) and along the return wire P770-WH (contact B).

4. Measure the voltage from contact A (wire P769-YL) to contact B (wire P770-WH).

Expected Result:

The voltage is approximately 8.0 ± 0.5 DCV.

Results:

• OK - The voltage is approximately 8.0 ± 0.5 DCV. Proceed to Test Step 3.

• NOT OK - The measurement is not correct.

  Repair: Repair the machine harness or replace the machine harness.

  STOP

Test Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT IN THE HARNESS.

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

2. Disconnect the machine harness connectors from the sensor and the ECM.

3. Measure the resistance between contact J2-24 (wire R914-OR) and all contacts that are used in the J1 and J2 harness connectors.

Expected Result:

The resistance is greater than 5000 ohms.

Results:

• OK - The resistance is greater than 5000 ohms. The circuit is correct. Proceed to Test Step 3.

• NOT OK - The resistance is less than 5 ohms. The signal circuit is shorted to another circuit in the harness.

  Repair: Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK THE SIGNAL CIRCUIT OF THE SENSOR FOR THE CORRECT FREQUENCY.

1. The key start switch remains in the OFF position.

2. At the back of the harness connector for the sensor, remove the 7X-1710 Multimeter Probe from contact A (wire P769-YL) and insert the probe along the signal wire R914-OR (contact C).

3. At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the ground wire P770-WH (contact B).

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

5. Measure the frequency of the sensor with the 146-4080 Digital Multimeter .

Expected Result:

The value of the Accelerator Pedal position sensor frequency is approximately 500 Hz.

Results:

• OK - The value of the Accelerator Pedal position sensor frequency is approximately 500 Hz. The Accelerator Pedal Position Sensor is operating correctly. Proceed to Test Step 4.

• NOT OK - The value of the Accelerator Pedal position sensor frequency is not 500 Hz. The Accelerator Pedal Position Sensor is NOT operating correctly.

  Repair: Replace the sensor.

  STOP

Test Step 4. CHECK IF THE DIAGNOSTIC CODE REMAINS.

1. Inspect the harness connectors and clean the contacts of the machine harness connectors.

2. Reconnect all harness connectors.

3. Turn the key start switch to the ON position.

4. Operate the machine.

5. Check the status of the CID 2795 FMI 08.

Expected Result:

The CID 2795 FMI 08 is not active.

Results:

• OK - The CID 2795 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 2795 FMI 08 is active.

  Repair: It is unlikely that the ECM has failed. 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".

  STOP