980K Wheel Loader Electrohydraulic System Caterpillar

Illustration 1	g02440816
Auxiliary Fourth Function electrical connections (dashed) that must be customer connected

Illustration 2	g02440817
Connections of Auxiliary Fourth Function (Thumbroller) Position Sensor

This diagnostic code is associated with the Auxiliary Fourth Function (Thumbroller) Position Sensor. The position sensor is located in the right joystick.

The Implement ECM 10 VDC sensor power supply and ground are used to power the position sensor.

The FMI 08 diagnostic code is activated when a frequency or signal pulse width is detected that is not within the expected range.

The position sensor is a PWM sensor that operates at a frequency of approximately 500 ± 100 Hz. The position sensor sends a PWM input signal to the Implement ECM. The variations in the duty cycle of the signal follow:

The possible causes of this diagnostic code are listed below:

• The sensor has failed or a mechanical connection has failed.

• Intermittent connections or poor connections

• The ECM has failed. This condition 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. Inspect the connections for the following:

• Connections are clean.

• Connections are secure.

• Connections are 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.

Test Step 1. CHECK THE DUTY CYCLE AND THE SIGNAL FREQUENCY AT THE SENSOR

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

2. At the machine harness connector X-C1 for the right joystick, use a 151-6320 Removal Tool to remove the signal wire G947-WH(White) and the socket at contact 4 from the harness connector. The machine harness connector X-C1 remains connected to the right joystick.

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

4. At the connector X-C1 for the right joystick, insert a 7X-1710 Multimeter Probe along the return contact of the sensor 2 (wire J765-BU(Blue)).

5. Use the other multimeter probe to make contact through the harness connector with pin 2 for the position sensor on the joystick connector.

6. With the auxiliary lever in the stationary condition, measure the frequency of the signal from the sensor.

7. Measure the duty cycle signal of the sensor between the connector contacts 2 and 4 of the right joystick. Slowly move the thumbroller to the full forward position and observe the duty cycle of the sensor signal. Slowly move the thumbroller to the full rearward position and observe the duty cycle of the sensor signal.

Expected Result:

The frequency of the position sensor is 500 ± 100 Hz. The duty cycle of the position sensor is correct according to the description at the beginning of this procedure.

Results:

• OK - The signal frequency and the duty cycle of the sensor is correct. The sensor is not the cause of the problem. Reconnect the signal wire and the socket in the connector of the machine harness J1 for the joystick. Proceed to Test Step 2.

• NOT OK - The signal frequency or the duty cycle of the position sensor is not correct according to the beginning of this procedure. The position sensor has failed. Verify that the power supply voltage going to the joystick is a steady 10.0 ± 0.4 DCV before replacing the sensor.

  Repair: The operation of the position sensor is not correct. Replace the assembly of the joystick assembly. After replacement, verify that the operation is correct before operating the machine.

  STOP

Test Step 2. CHECK FOR AN OPEN IN THE SIGNAL CIRCUIT

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

2. Disconnect the machine harness connector X-C1 from the right joystick. At the connector of the machine harness, connect a jumper wire between the signal contact at 4 (wire G947-WH(White)) and frame ground.

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

4. Observe the status of the active CID 2285 FMI 08 diagnostic code.

Expected Result:

The active diagnostic code CID 2285 FMI 08 is no longer active. A CID 2285 FMI 04 diagnostic code becomes active when the signal wire (G947-WH(White)) is grounded.

Results:

• YES - The active diagnostic code CID 2285 FMI 08 is no longer active. A CID 2285 FMI 04 diagnostic code has been activated after the signal wire is grounded. Proceed to Test Step 3.

• NO - The CID 2285 FMI 08 diagnostic code remains active. The status of the active diagnostic code does not change when the signal wire is grounded. There is an open or a poor connection in the signal wire.

  Repair: Check the signal circuit for an open or for a poor connection. Repair or replace the machine harness.

  STOP

Test Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Perform the following:

   • Visually inspect the harness connectors.

   • Clean the contacts of the harness connectors.

   • Visually inspect the insulation of the wires for damage that can be 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. Verify the following:

   • Connectors are fully seated.

   • The clips for each connector are fastened completely.

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

5. Operate the machine.

6. Check the status of the CID 2285 FMI 08.

Expected Result:

The CID 2285 FMI 08 is not active.

Results:

• OK - The CID 2285 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 2285 FMI 08 is active. The diagnostic code has not been corrected.

  Repair: If available, perform a Wiggle Test on the machine wiring harness with the Caterpillar Electronic Technician (Cat ET) service tool. The Wiggle Test can detect the following in the machine wiring harness:

  • Momentary shorts

  • Intermittent shorts

  • Opens
  If the cause of the active diagnostic code is not found, the Implement ECM may have failed.

  Failure of the ECM is unlikely. Exit this procedure and perform this procedure again. If the cause of the failure is not found, replace the ECM. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may effect repair time. If the cause of the diagnostic code is not found, replace the Implement ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP