14L Motor Grader Implement Electronic Control System Caterpillar

Illustration 1	g03172818
Articulation Lever Position Sensor connections

The position sensor for the articulation lever is located in the assembly of the left joystick. The sensor provides an input signal to the ECM. This diagnostic code is activated when the ECM reads the input signal from the position sensor for the articulation lever and the voltage of the signal is above normal.

The articulation position sensor receives power from the 8V power supply of the Implement ECM. The sensor is internally connected to the ground that is supplied by the 5V sensor return of the Transmission/Chassis ECM and to the Implement ECM. 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 ± 5% at the joystick full articulate left position to approximately 90 ± 5% 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 active diagnostic code are listed:

• The circuit for the sensor power supply is open.

• The circuit for the sensor return is open.

• The signal circuit is open.

• The signal circuit is shorted to the sensor power supply.

• The sensor has failed.

• The ECM has failed. ECM failure 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 position sensor of the articulation lever 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 a 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 03 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 SENSOR POWER SUPPLY CIRCUIT

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

2. At the J1 harness connector for the left joystick, insert 7X-1710 Multimeter Probes along the +V1 power supply contact J1-1 (wire R800-OR(Orange)) and along ground 1 contact J1-3 (wire L731-BR(Brown)). Do not disconnect the machine harness from the J1 connector.

3. Measure the DC voltage of the sensor power supply.

4. At the harness connectors for the left joystick, remove the multimeter probe that is inserted along the ground 1 contact J1-3 and insert the probe along ground 4 contact J3-3 (wire 998-BR(Brown)). Do not disconnect the machine harness from the J3 connector.

5. Measure the DC voltage of the sensor power supply.

Expected Result:

Each voltage measurement is approximately 8.0 ± 0.4 VDC.

Results:

• OK. - Each voltage measurement is approximately 8.0 ± 0.4 VDC. The power supply for the sensor is correct. Proceed to Test Step 2.

• NOT OK. - Both of the voltage measurements are less than 8.0 ± 0.4 VDC. The power supply for the sensor is not correct.

  Repair: If both of the voltage measurements are not correct, the problem is most likely in the power circuit wire. This condition will cause multiple diagnostic codes to activate.

  Refer to the complete Electrical System Schematic of the machine. Examine all of the connectors that are in the circuits. Ensure that the connections are clean, that all connections are secure and that all connections are in good condition.

  For troubleshooting the ECM power supply that is providing power to the sensor, refer to the CID 0041 diagnostic code procedures in the troubleshooting section of the manual for the Implement ECM.

  Repair the defective power supply circuit before proceeding with this procedure.

  STOP

• NOT OK. - One of the voltage measurements is not correct.

  Repair: If one of the voltage measurements is correct and the other voltage measurement is not correct, there is a problem in the ground circuit that registered the bad measurement. This condition will not cause this diagnostic code to activate. There is another problem causing this active diagnostic code, however, the ground circuit must be repaired before proceeding with this procedure.

  Do not operate the machine with only one ground connection for the left joystick.

  Repair the defective ground circuit or power supply circuit before proceeding with this procedure.

  After repairing the faulty ground circuit, proceed to Test Step 2.

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

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

2. Disconnect the three machine harness connectors from the left joystick. At the harness connectors for the joystick, place a jumper wire between the ground 4 contact J3-3 (wire 998-BR(Brown)) and the signal contact J2-1 (wire K758-BU(Blue)).

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

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

5. While observing the resistance measurement, wiggle the ECM connector and the sensor connector. Gently pull on the wires and move the wires around 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 signal circuit of the sensor and the ground circuits of the sensor are 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 5Ωbut 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. 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 SIGNAL CIRCUIT FOR A SHORT

The key start switch and the disconnect switch remain in the OFF position. The machine harness connectors for the joystick remain disconnected.

1. Remove the jumper wire that was installed in the last step.

2. At the J2 machine harness connector for the Implement ECM, measure the resistance from the sensor signal contact J2-26 (wire K758-BU(Blue)) to all of the other J1 and J2 contacts that are used for the Implement ECM.

Expected Result:

Each resistance measurement is greater than 5kΩ.

Results:

• OK. - Each resistance measurement is greater than 5kΩ. The resistance measurements do not indicate a short in the circuit. Proceed to Test Step 4.

• NOT OK. - A resistance measurement is less than 5kΩ.

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

  Refer to the complete Electrical System Schematic of the machine. Check all of the connectors that are in the sensor circuit. Ensure that all connections are clean, that all connections are secure and that all 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 4. CHECK THE SIGNAL AT THE SENSOR

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

1. Inspect all of the harness connectors for the joystick and the ECM. Clean the contacts of the harness connectors and check the wires for damage to the insulation. Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are completely fastened.

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

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

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

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

Expected Result:

The duty cycle of the position sensor of the articulation lever is correct according to the description at the beginning of this procedure.

Results:

• OK. - 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 machine harness connector for the joystick. Proceed to Test Step 5.

• NOT OK. - 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 articulation lever position sensor signal is not correct according to the description at the beginning of this procedure, replace the left joystick assembly. After replacement of the assembly of the joystick, verify that the operation of the new assembly of the joystick is correct before operating the machine.

  STOP

Test Step 5. 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 sensor circuit.

3. Reconnect all harness connectors. 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. Determine if the CID 2146 FMI 03 diagnostic code is active.

Expected Result:

The CID 2146 FMI 03 diagnostic code is not active.

Results:

• OK. - The CID 2146 FMI 03 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 2146 FMI 03 diagnostic code 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