259D Compact Track Loader – MID 039 – CID 3700 – FMI 08

Conditions Which Generate This Code:

This diagnostic code is recorded when the ECM determines that the signal of the position sensor for the third function has an abnormal pulse width. The sensor is a PWM sensor.

The possible causes for this diagnostic code are listed below:

• The circuit for the +battery to the sensor has an intermittent connection.

• The return circuit from the sensor has an intermittent connection.

• The signal circuit from the sensor has an intermittent connection.

• The sensor has failed.

Note: 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 of the connections in the circuit are clean and that all connections are secure. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. Each connector contact should withstand 45 N (10 lb) of pull. Each wire should remain in the connector body. This test checks whether the wire was properly crimped in the contact and whether the contact was properly inserted into the connector.

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 3700 FMI 08 is active before performing this procedure.

Use a digital multimeter for the measurements in the procedure.

System Response:

The implements will stop working until the right-hand joystick is returned to the center position. After the joystick has been centered, the implements will behave normally, but the Self Level, Return-to-Dig, and Work Tool Positioner features will be disabled. The green Self Level icon on the machine left-hand display will no longer light up when the Self Level Cab switch is turned on. In the case of an intermittent fault, these features will be disabled until the next key cycle.

Test Step 1. CHECK FOR POWER AT THE SENSOR.

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

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

3. At the back of the harness connector for the sensor, insert a multimeter probe along the voltage supply wire (contact 1).

4. Measure the voltage from contact 1 to frame ground.

Expected Result:

The voltage is 8 VDC.

Results:

• OK - The voltage is 8 VDC. Proceed to Test Step 2.

• NOT OK - The voltage is not 8 VDC. The + battery circuit in the machine harness has failed.

  Repair: Replace the machine harness or repair the machine harness.

  STOP

Test Step 2. CHECK FOR PROPER GROUND AT THE SENSOR.

1. The machine harness remains connected to the sensor.

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

3. Remove the multimeter probe from the voltage supply wire (contact 1).

4. At the back of the harness connector for the sensor, insert a multimeter probe along the ground wire (contact 2).

5. Measure the resistance from contact 2 to frame ground.

Expected Result:

The resistance is less than 5 ohms.

Results:

• OK - The resistance is less than 5 ohms. The ground circuit is correct. Proceed to Test Step 3.

• NOT OK - The resistance is greater than 5 ohms. The ground circuit in the machine harness has failed.

  Repair: Replace the machine harness or repair the machine harness.

  STOP

Test Step 3. CHECK THE WIRING HARNESS OF THE SENSOR FOR AN OPEN CIRCUIT.

1. The key start switch and the disconnect switch remain in the OFF position.

2. Disconnect the machine harness from the sensor.

3. At the harness connector for the sensor, connect a jumper wire between contact 2 and contact 3.

4. Disconnect the machine harness connector(s) from the ECM.

5. At the harness connector for the ECM, measure the resistance between contact J1-45 (wire P770-WH) and contact J2-15 (wire A426-BU).

Expected Result:

The resistance measurement is less than 5 ohms.

Results:

• OK - The resistance measurement is less than 5 ohms. The circuit is correct. Proceed to Test Step 4.

• NOT OK - The resistance is greater than 5 ohms. The circuit is not correct. There is an open circuit in the wiring harness.

  Repair: There is an open circuit in the wiring harness. Repair the wiring harness or replace the wiring harness.

  STOP

Test Step 4. CHECK THE WIRING HARNESS OF THE SENSOR FOR A SHORT TO THE +BATTERY CIRCUIT.

1. The key start switch and the disconnect switch remain in the OFF position.

2. The machine harness remains disconnected from the sensor. Remove the jumper wire that was installed in the previous step.

3. The machine harness connector(s) remains disconnected from the ECM.

4. At the machine harness connector for the ECM, measure the resistance from the signal contact J2-15 (wire A426-BU) of the machine harness to all contacts that are used in the machine harness connectors for the Machine ECM.

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 5.

• 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 J2-15 (wire A426-BU) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. 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.

2. Disconnect the machine harness from the sensor.

3. Disconnect the machine harness connector(s) from the ECM.

4. At the machine harness connector for the ECM, measure the resistance from the signal contact J2-15 (wire A426-BU) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors for the Machine ECM.

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 6.

• 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 J2-15 (wire A426-BU) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.

  STOP

Test Step 6. CHECK THE SENSOR

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

2. Ensure that the diagnostic code is active.

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

Expected Result:

The FMI 04 changes to an FMI 03

Results:

• OK - The FMI 04 changes to an FMI 03. The sensor has failed.

  Repair: Repair of repace to sensor.

  STOP

• NOT OK - The FMI 04 code remains active. Proceed to test step 7.

Test Step 7. CHECK IF THE DIAGNOSTIC CODE REMAINS.

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.

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

3. 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 completely fastened.

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

5. Operate the machine.

6. Check the status of the diagnostic code.

Expected Result:

The diagnostic code is no longer active.

Results:

• YES - The diagnostic code is not active. The initial diagnostic code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.STOP

• NO - The diagnostic code 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. Prior to replacing an ECM, always contact your dealership 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