| |
| Illustration 1 | g03172818 |
|
Articulation Lever Position Sensor connections | |
The position sensor of 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 recorded when the ECM reads the input signal from the position sensor of the articulation lever and the voltage of the signal is below normal.
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 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:
- The signal circuit is shorted to ground.
- The sensor has failed.
- The ECM has failed. This is unlikely.
Note: Ensure that the CID 2146 FMI 04 diagnostic code is active before performing this procedure.
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.
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
- Turn the disconnect switch and the key start switch to the ON position.
- Disconnect the machine harness connector J2 from the left joystick. Observe the status of the active CID 2146 FMI 04 diagnostic code.
Expected Result:
The status of the CID 2146 FMI 04 diagnostic code did not change when the joystick connector was disconnected. A CID 2146 FMI 03 diagnostic code has NOT been activated the ECM. The CID 2146 FMI 04 diagnostic code remains active when the joystick connector is disconnected.
Results:
- YES. - The CID 2146 FMI 04 diagnostic code remains active when the joystick connector is disconnected. The sensor is not causing the problem. Proceed to Test Step 2.
- NO. - The CID 2146 FMI 04 diagnostic code is no longer active when the joystick connector is disconnected. A CID 2146 FMI 03 diagnostic code has been activated by the ECM when the joystick connector is disconnected. The machine harness and the ECM are operating correctly.
Repair: The articulation position sensor is causing the problem. There is an internal short to ground in the left joystick. 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 THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
- The connector of the joystick J2 remains disconnected from the machine harness.
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the J1 and J2 machine harness connectors from the Implement ECM.
- At machine harness connector J2 for the Implement ECM, measure the resistance from contact J2-26 (wire K758-BU(Blue)) 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 5kΩ.
Results:
- OK. - Each resistance measurement is greater than 5kΩ. The machine harness is correct. Proceed to Test Step 3.
- NOT OK. - One or more of the resistance measurements is less than 5kΩ.
Repair: There is a short in the machine harness. The short is between the signal circuit and either the frame ground or 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 3. 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 sensor 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 2146 FMI 04 diagnostic code is active.
Expected Result:
The CID 2146 FMI 04 diagnostic code is not active.
Results:
- OK. - The CID 2146 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 2146 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 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