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| Illustration 1 | g03172896 |
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Automatic Neutral Articulation Switch connections | |
This diagnostic code is associated with the automatic neutral articulation switch that is located on the left joystick handle. The switch supplies two, switch to ground type inputs to the Implement ECM. The ECM expects one of the two switch inputs to be grounded at all times. When the ECM detects that both of the switch inputs are grounded at the same time, the ECM will activate an FMI 04 diagnostic code for voltage below normal.
The automatic neutral articulation switch is connected to ground at the Implement ECM and the Transmission Chassis ECM 5V sensor return (ECM ground). The switch must lose both grounds in order to disrupt the switch operation. The illustration above indicates the power and ground connections for the switch.
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.
Possible conditions that can cause this diagnostic code are listed:
- One or both of the switch inputs is shorted to a ground source.
- The switch has failed.
- The ECM has failed. This 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. 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 original diagnostic code has been corrected.
Test Step 1. CHECK THE SWITCH
- Turn the disconnect switch and the key start switch to the ON position.
- Ensure that the diagnostic code is active.
- Observe the status of the diagnostic code while disconnecting left joystick J2 connector from the machine harness.
Expected Result:
The CID 2147 FMI 04 diagnostic code will remain active if the switch is not the cause of the diagnostic code. The switch is the cause of the diagnostic code if the CID 2147 FMI 04 diagnostic code is NO longer active and a CID 2147 FMI 03 diagnostic code becomes active.
Results:
- OK. - The CID 2147 FMI 04diagnostic code remains active. The switch has not failed. Proceed to Test Step 3.
- NOT OK. - The CID 2147 FMI 04 diagnostic code is NO longer active. A CID 2147 FMI 03 diagnostic code becomes active when the J2 connector is disconnected. The machine harness and the ECM are operating correctly. The switch may be faulty. Verify that the switch is not operating correctly. Proceed to Test Step 2.
Test Step 2. CHECK THE SWITCH OPERATION
The left joystick connector J2 remains disconnected from the machine harness. The disconnect switch and the key start switch remain in the OFF position.
- Disconnect the joystick J1 connector from the machine harness.
- At the joystick connectors, measure the resistance (continuity) between ground 1 contact J1-3 and the joystick N/O switch contact J2-3 when the switch is not depressed and when the switch is depressed.
- At the joystick connectors, measure the resistance (continuity) between ground 1 contact J1-3 and the joystick N/C switch contact J2-4 when the switch is not depressed and when the switch is depressed.
Expected Result:
When the switch is NOT depressed, the measurement results are as listed:
J1-3 (ground) to J2-3 (N/O) - No continuity (Open)
J1-3 (ground) to J2-4 (N/C) - Continuity (Closed)
When the switch IS depressed, the measurement results are as listed:
J1-3 (ground) to J2-3 (N/O) - Continuity (Closed)
J1-3 (ground) to J2-4 (N/C) - No continuity (Open)
Results:
- OK. - The continuity checks between ground contact J1-3 to the switch contacts are correct. The switch is operating correctly. Proceed to Test Step 3.
- NOT OK. - The continuity checks between the ground contact J1-3 to the switch contacts are not correct. The switch is not working correctly switch.
Repair: The automatic neutral articulation switch is not correct. Replace the joystick faceplate. Refer to Special Instruction, REHS7448, "Procedure To Remove And Replace The Left-Hand Joystick Push-Button Faceplate on M Series And M Series 2 Motor Graders". Verify that the operation of the joystick is correct before operating the machine.
STOP
Test Step 3. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
The connector for the left joystick J2 remains disconnected from the machine harness. The disconnect switch and the key start switch remain in the OFF position.
- Disconnect the J1 and J2 machine harness connectors from the ECM.
- At machine harness connector J2 for the ECM, measure the resistance from contact J2-23 (wire U744-OR(Orange)) to frame ground. Measure the resistance to all of the contacts that are used in the J1 and J2 connectors for the ECM.
- At machine harness connector J2 for the ECM, measure the resistance from contact J2-28 (wire U745-PK(Pink)) to frame ground. Measure the resistance to all of the contacts that are used in the J1 and J2 connectors for the ECM.
Expected Result:
Each resistance measurement is greater than 5kΩ.
Results:
- OK. - Each resistance measurement is greater than 5kΩ. The switch circuits are not shorted to another circuit in the machine harness. Proceed to Test Step 4.
- 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 switch 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 STATUS OF THE DIAGNOSTIC CODE
- 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.
- Perform a
45 N (10 lb) pull test on each of the wires that are associated with the switch circuit. - Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are completely fastened.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Determine if the CID 2147 FMI 04 diagnostic code is active.
Expected Result:
The CID 2147 FMI 04 diagnostic code is not active.
Results:
- OK. - The CID 2147 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 2147 FMI 04 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 (TC) 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