950K and 962K Wheel Loaders Electrohydraulic System Caterpillar

Illustration 1	g02442696
(1) Attachment two lever implement controls with auxiliary third function lever

Illustration 2	g02652900
Connections of the Auxiliary Third Lever Position Sensor

This diagnostic code is recorded when the Implement ECM reads the Auxiliary Third Lever Position Sensor and the voltage is below normal. The position sensor is located in the implement control lever.

The duty cycle of the PWM sensor input signal will change according to the amount of lever movement on the forward / rearward axis. Each position sensor signal operates at approximately 500 ± 100 Hz.

The lever position sensor is supplied system voltage through the right column, fuse F39 in the switched upper fuse panel (10A - circuit 146-GY). The sensor is supplied an ECM ground circuit (C214-BK) connection from the Implement ECM J1-70 contact.

This ground circuit is used for ECM location code ground connections and for ground supply connections. Most of the switches and sensors that are connected to the ECM also use this ground circuit.

The following table indicates the PWM duty cycles that the ECM will consider as acceptable in the indicated standard lever and auxiliary lever positions.

The ECM will activate an FMI 04 diagnostic code for a specific lever when the duty cycle is less than 4%.

The possible conditions that could cause this diagnostic code are:

• The signal circuit is shorted to ground.

• The sensor has failed.

• The ECM has failed. This condition is unlikely.

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. Inspect the connections for the following:

• Connections are clean.

• Connections are secure.

• Connections are in good condition.

Note: 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 SENSOR

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

2. Disconnect the machine harness connector C4 from the implement control lever. Observe the status of the active CID 0487 FMI 04 diagnostic code.

Expected Result:

The status of the CID 0487 FMI 04 diagnostic code did not change when the connector for the lever assembly was disconnected. A CID 0487 FMI 03 diagnostic code has not been activated by the ECM. The CID 0487 FMI 04 diagnostic code remains active when the connector for the lever assembly is disconnected.

Results:

• OK - The CID 0487 FMI 04 diagnostic code remains active when the connector for the lever assembly is disconnected. The sensor is not the cause of the problem. Proceed to Test Step 2.

• NOT OK - The CID 0487 FMI 04 diagnostic code is no longer active when the connector for the lever assembly is disconnected. A CID 0487 FMI 03 diagnostic code is activated by the ECM when the connector for the lever assembly is disconnected. The machine harness and the ECM are operating correctly.

  Repair: The operation of the position sensor is the cause of the problem. Replace the implement control lever assembly. After replacement, verify that the operation is correct before operating the machine.

  STOP

Test Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND

1. The connector for the steering lever C4 remains disconnected from the machine harness.

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

3. Disconnect the J1 and J2 machine harness connectors from the Implement ECM.

4. At machine harness connector J2 for the ECM, measure the resistance from contact J2-26 (wire H722-GN(Green)) to frame ground and measure the resistance to all of the other J1 and J2 contacts that are used for the Implement 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 3.

• NOT OK - One or more of the resistance measurements is not correct. The machine harness has failed.

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

  Refer to the Electrical Schematic of the machine. Check all of the connectors that are in the sensor circuit. Check all of the connectors that are in the sensor circuit. Inspect the connections for the following:

  • Connections are clean.

  • Connections are secure.

  • Connections are in good condition.
  For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness 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 sensor circuit.

3. Reconnect all harness connectors. Verify the following:

   • The connectors are fully seated.

   • The clips for each connector are fastened.

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

5. Operate the machine.

6. Determine if the CID 0487 FMI 04 diagnostic code is active.

Expected Result:

The CID 0487 FMI 04 diagnostic code is not active.

Results:

• OK - The CID 0487 FMI 04 diagnostic code 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 0487 FMI 04 diagnostic code 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 ECM that has activated this diagnostic code may have failed.

  Exit this procedure and perform this procedure again. If the cause of the failure is not found, contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may effect repair time.

  If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP