VALVE GP-LOAD CONTROL 4215433 - Caterpillar

Illustration 1 g01791234
Partial Schematic of the "CAN 2" NetworkIf an averaging beam is connected to the system, an additional CAN resistor is added and that will affect the resistance values of the system.Test Step 1. CYCLE THE POWER TO THE SYSTEM
Turn the key start switch for the machine to the OFF position.
Turn the key start switch for the machine to the ON position.
Use the "Sensor Data" screen to check the status of the system components.Expected Result:All of the components are connected.Results:
YES - All of the components are connected.Repair: The issue was caused by the internal CAN data link of the display. Cycling the power has reset the display. Return the machine to normal operation.STOP
NO - The diagnostic code is still active. Proceed to Test Step 2.Test Step 2. CHECK THE RESISTANCE OF THE "CAN 2" CIRCUIT
Place the key start switch and the disconnect switch in the OFF position.
Take the following measurement at the connector for the sensors. Measure the resistance between contact "D" (wire L856-YL) and contact "H" (wire L857-GN).
Table 1
Configuration     Expected Resistance    
No Averaging Beam     60 6 ohms    
One Averaging Beam     40 4 ohms    
Two Averaging Beams     30 3 ohms    Expected Result:The resistance measurement that was measured corresponds to the values that are listed in Table 1.Results:
YES - The resistance measurement is correct. Proceed to Test Step 4.
NO - The resistance measurement is NOT correct. Proceed to Test Step 3.Test Step 3. CHECK THE TERMINATION RESISTOR FOR THE "CAN 2" CIRCUIT
Place the key start switch and the disconnect switch in the OFF position.
Disconnect the 4-pin connector for both termination resistors. Disconnect the 3-pin connector for the other two termination resistors.
Measure the resistance across contact "3" (wire L856-YL) and contact "4" (wire L857-GN) for both of the 4-pin resistors. Note the resistance.
Measure the resistance across contact "A" (wire L856-YL) and contact "B" (wire L857-GN) for both of the 3-pin resistors. Note the resistance.Note: The 3-pin resistors are located in the averaging beam harness. Your system may not contain these resistors.Expected Result:The resistance measurements are 120 12 ohms.Results:
YES - The resistance measurements are 120 12 ohms. Reconnect the resistors. Proceed to Test Step 5.
NO - One or both resistance measurements is NOT 120 12 ohms. Repair: Replace the termination resistor(s) that did not measure 120 12 ohms.STOPTest Step 4. CHECK THE CAN DATA LINK FOR FAILED COMPONENTSNote: Ensure that the diagnostic code is active prior to performing this step.
Place the key start switch and the disconnect switch in the "ON" position.
Disconnect the following components for the system one at a time. After each component has been disconnected, check the display in order to verify that the diagnostic code is no longer active.
Angle Sensor
Sonic Tracer(s)
Contact Sensor
Averaging BeamExpected Result:Removing one of the system components will cause the diagnostic code to become inactive.Results:
YES - Removing one of the system components will cause the diagnostic code to become inactive.Repair: The last component that was removed from the system