ELBOW 0026223 - Caterpillar

Illustration 1 g01861893
This procedure is associated with the harnesses that connect to the AccuGrade Grade Control System or the internal AccuGrade CAN data link of an AccuGrade component. System components may be experiencing intermittent communications. This results in lost system data.Test Step 1. CYCLE THE POWER TO THE SYSTEM.
Turn off the display.
Turn the key start switch for the machine to the OFF position.
Turn the key start switch for the machine to the ON position.
Turn on the display.
Check the status of the system components in the "Diagnostics" screen.Make sure that all the required components are shown as "Connected".Expected Result:All system components show as "Connected" in the "Diagnostics" screen.Results:
YES - All of the system components are shown as "Connected" in the "Diagnostics" dialog.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 - All system components do not show as "Connected" in the "Diagnostics" dialog. Proceed to Test Step 2.Test Step 2. CHECK THE RESISTANCE OF THE CAN DATA LINK.
Place the key start switch and the disconnect switch in the OFF position.
Take the following measurement at the connector for the sensor that is communicating on the AccuGrade CAN data link. Measure the resistance between contact "C" (wire K960-PK) and contact "D" (wire K961-GN).Expected Result:The resistance measurement is 60 6 ohms.Results:
YES - The resistance measurement is 60 6 ohms. Proceed to Test Step 4.
NO - The resistance measurement is NOT 60 6 ohms. Proceed to Test Step 3.Test Step 3. CHECK THE TERMINATION RESISTOR.
Disconnect the 3-pin connector for both of the termination resistors.
Measure the resistance between contact "A" and contact "B" for one resistor. Measure the resistance between contact "A" and contact "B" for the other resistor. Note the resistance.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 4.
NO - One or both resistance measurements is NOT 120 12 ohms.Repair: Replace the termination resistors that did not measure 120 12 ohms.STOPTest Step 4. CHECK THE CAN DATA LINK FOR A SHORT TO GROUND.
The key start switch and the disconnect switch remain in the OFF position.
Measure the resistance between contact "A" (wire K960-PK) and frame ground. Measure the resistance between contact "B" (wire K961-GN) and frame ground. Note the resistance.Expected Result:The resistance measurements are greater than 5000 ohms.Results:
YES - The resistance measurements are greater than 5000 ohms. Proceed to Test Step 5.
NO - One or both resistance measurements are less than 5 ohms.Repair: The CAN data link is shorted to ground. Repair the harness or replace the harness.STOPTest Step 5. CHECK THE CAN DATA LINK FOR A SHORT TO +BATTERY.
Turn the disconnect switch and the key start switch to the ON position.
Measure the voltage between contact "A" (wire K960-PK) and frame ground. Measure the voltage between contact "B" (wire K961-GN) and frame ground. Note the voltage.Expected Result:The