14L Motor Grader Implement Electronic Control System Caterpillar

Illustration 1	g03172818
Articulation Lever Position Sensor connections

The articulation lever position sensor is located in the left joystick assembly. The sensor provides an input signal to the ECM. 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 articulation position sensor receives power from the Implement ECM 8V power supply. The sensor is internally connected to the ground from the Implement ECM and to the ground from the Implement ECM 5V sensor return (ECM ground). The sensor must lose both grounds in order to lose the ground connection. The illustration above indicates the power and ground connections for the position sensor.

Note: For a schematic of the internal power and ground assignments for each individual component in the left joystick, refer to the Systems Operation, "Features" section of this manual.

The position sensor is a PWM sensor that operates at a frequency of 500 ± 100 Hz. The position sensor sends a PWM input signal to the Implement ECM. The duty cycle of the signal will vary from approximately 10% at the joystick full articulate left position to approximately 90% at the joystick full articulate right position. When the joystick is in the center (neutral) 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.

Points to Consider When This Code Is Active:

Note: If a CID 0041 diagnostic code for the 8V power supply has been activated by the Implement ECM (MID 082), investigate the problem and fix the problem before proceeding with this procedure.

Note: The correct operating temperature range for the sensor is −40 °C (−40.0 °F) to 75 °C (167.0 °F). If an FMI 03 or an FMI 08 diagnostic code becomes active for an articulation lever position sensor when the cab environment is at extreme temperatures, normalize the cab environment in order to keep the sensor operating in the acceptable temperature range. After temperature normalization, verify that the CID 2146 FMI 08 diagnostic code is active before performing this procedure.

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, that all connections are secure and that all 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

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

1. At the machine harness connector J2 for the left joystick, use a 151-6320 Removal Tool to remove the signal wire (wire K758-BU(Blue)) and the socket at contact J2-1. The machine harness connector J2 remains connected to the connector for the left joystick.

2. At the back of the joystick connector J1 and J2, insert 7X-1710 Multimeter Probes along the sensor signal contact J2-1 and the return contact at J1-3.

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

4. With the joystick stationary, measure the frequency of the signal from the sensor.

5. Observe the measurement and wiggle the connector of the joystick. Gently pull on the wires and wiggle the wires.

6. Measure the duty cycle of the sensor at the connector contacts of the joystick J2-1 and J1-3. Rotate the joystick through the full range of the sensor that is described at the beginning of this procedure.

7. Observe the measurement and wiggle the connector of the joystick. Gently pull on the wires and wiggle the wires.

Expected Result:

The frequency of the articulation lever position sensor signal is 500 ± 100 Hz. The duty cycle of the articulation lever position sensor is correct according to the description at the beginning of this procedure. The frequency and the duty cycle are stable during the manipulation of the harness connector and the wiring.

Results:

• OK. - The signal frequency and the duty cycle of the sensor is correct. The sensor is not causing the problem. Reconnect the signal wire and the socket in the machine harness connector for the joystick. Verify that all the wires of the joystick are secure in the connector. Proceed to the next step. Proceed to Test Step 2.

• NOT OK. - The signal frequency or the duty cycle of the articulation lever position sensor is NOT correct according to the description at the beginning of this procedure. The sensor has failed.

  Repair: Perform this test step again in order to verify that the sensor signal is not correct.

  If the signal from the position sensor of the articulation lever is not correct according to the description at the beginning of this procedure, replace the assembly of the left joystick. After replacement of the assembly of the joystick, verify that the operation of the assembly of the new joystick 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 J2 and J3 from the left joystick. At machine harness sensor connectors, place a jumper wire between the sensor return contact at J3-3 (wire 998-BR(Brown)) and the signal contact at J2-1 (wire K758-BU(Blue)).

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

4. At the harness connectors for the ECM, measure the resistance from return contact J1-21 (wire 998-BR(Brown)) to signal contact J2-26 (wire K758-BU(Blue)).

5. Observe the resistance measurement and wiggle the ECM connector and the sensor connector. Gently pull on the wires and wiggle the wires for both connectors.

Expected Result:

The resistance measurement is less than 5Ω at all times during the manipulation of the wiring harness and connectors.

Results:

• OK. - The resistance measurement is less than 5Ω. The sensor signal circuit is not open in the machine harness. Proceed to Test Step 3.

• NOT OK. - The resistance measurement for the signal circuit is greater than 5Ω. There is an open or a bad connection in the circuit.

  Repair: Check the signal circuit for opens or for a bad connection.

  A resistance measurement that is greater than 5Ω but less than 5kΩ would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5kΩ would indicate an open in the circuit.

  Refer to the complete Electrical System Schematic of the machine. Check all of the connectors that are in the sensor signal circuit or in the ground circuits. Ensure that all connections are clean, that all connections are secure and that all connections are in good condition. Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Inspect the harness connectors. Clean the contacts of the harness connectors. 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. Observe 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 CID 2146 FMI 08.

Expected Result:

The CID 2146 FMI 08 is not active.

Results:

• OK. - The CID 2146 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 2146 FMI 08 is active. The diagnostic code has not been corrected.

  Repair: Check the circuit again. Use the Caterpillar Electronic Technician (ET) service tool, if available, in order to perform a wiggle test on the machine wiring harness. The wiggle test can detect momentary or intermittent shorts or opens in the machine wiring harness.

  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 of your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time.

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

  STOP