PLATE AS 4646096 - Caterpillar

Illustration 1 g01324491
(1) The Laser receiver and the electric mast are not connected. (2) The Laser receiver is not connected.The device status icon for the laser receiver will show as a simulated icon on the display.Test Step 1. INSPECT THE HARNESS.Refer to Electrical Schematic, RENR8191.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the harness connectors for the right/left electric mast. Disconnect the harness connectors for the right/left laser receivers.
Carefully inspect each harness for signs of abrasion, nicks, or cuts.The following areas are locations that should be checked:
Exposed insulation
Points of rubbing wire
Check the connectors for moisture or corrosion.Note: If corrosion is evident on the contacts or the connector, use only denatured alcohol to remove the corrosion. Use a cotton swab or a soft brush to remove the corrosion. Do not use cleaners that contain trichloro-ethylene because trichloro-ethylene may damage the connector.Expected Result:The "AccuGrade Laser" system harnesses should be free of the following:
Corrosion
Moisture
AbrasionResults:
OK - The AccuGrade Laser system harnesses are free of corrosion, moisture and abrasion. Proceed to test step 2.
NOT OK - A problem exists with the connector, the wiring or the wiring harness.Repair: Repair the affected AccuGrade Laser system harness or replace the affected AccuGrade Laser system harness. Proceed to test step 2.Test Step 2. CHECK IF THE DIAGNOSTIC CODE REMAINS
Reconnect the AccuGrade Laser system harnesses to the left electric mast.
Reconnect the AccuGrade Laser system harnesses to the left laser receiver.
Turn the key start switch and the disconnect switch to the ON position.Expected Result:The diagnostic code is no longer active.Results:
OK - The diagnostic code is no longer active. The initial diagnostic code was probably caused by a poor electrical connection and/or a short at one of the harness connectors that was disconnected and then reconnected. Resume normal machine operation.STOP
NOT OK - The diagnostic code is still active. Proceed to Test Step 3.Test Step 3. CHECK THE TERMINATION RESISTOR.
Turn the key start switch and the disconnect switch for the machine to the OFF position.
Disconnect the 3-pin connector from both of the termination resistors.
Measure the resistance between contact A (wire L854-YL) and contact B (wire L855-GN) for both resistors. Note the resistance.Expected Result:The resistance measurements are 120 12 ohms.Results:
YES - The resistance measurements are 120 12 ohms. Reconnect the resistors.Repair: If the diagnostic code "LR 21" is still active, contact your Caterpillar dealership.STOP
NO - One or both of the resistance measurements is NOT 120 12 ohms. Repair: Replace the termination resistor(s) that did not measure 120 12 ohms.STOP