AccuGrade® Laser (CB420) Caterpillar

Troubleshooting for the Hydraulic System

Problem List (Auto Mode)

• "The AccuGrade - Grade Control System will not engage in the automatic mode and the green light does not illuminate."

• "Poor Performance"

Probable Causes (Auto Mode)

The AccuGrade - Grade Control System will not engage in the automatic mode and the green light does not illuminate.

Note: TheAccuGrade - Grade Control System is programmed to disengage from the auto mode if the machine implements are not moved in 60 seconds and the machine is in neutral.

1. The parking brake is on.

   1. Disengage the parking brake.

2. Electrical system diagnostics

   1. Use Caterpillar Electronic Technician (Cat ET) in order to check for any system diagnostic codes.

      Note: Refer to the Troubleshooting, "Test Valves Menu" for more information.

   2. Check the Caterpillar Monitoring System for any diagnostic codes.

   3. Check the display for the AccuGrade - Grade Control System for any diagnostic codes.

      ReferenceRefer to the Troubleshooting, "Determining Detected Faults (Display)" for more information.

Poor Performance

1. Improper setting of the valve speed.

   ReferenceRefer to Testing and Adjusting, "Blade Reaction Time - Adjust (Valve Speed)" for more information on this procedure.

2. Improper Calibration

   ReferenceRefer to Testing and Adjusting, "Linked Elevation (Dual Mast) - Calibrate" and Testing and Adjusting, "Bank (Grade Control) - Calibrate" for more information on this procedure.

3. Improper setup for the Laser transmitter

   ReferenceRefer to Operation and Maintenance, SEBU7811, "Laser Transmitter Setup Information (Dual Mast System)" for more information on setup of the laser transmitter.

4. Improper setup of the laser receiver

   ReferenceRefer to Operation and Maintenance, SEBU7811, "Startup (Dual Mast System)" for more information on the setup of the laser receiver.

5. There is excessive air in the hydraulic system.

   1. Bleed the air from the hydraulic system.

6. Operating conditions are not suitable for the AccuGrade - Grade Control System.

   ReferenceRefer to Operation and Maintenance, SEBU7811, "General Information" for more information on usage of the AccuGrade - Grade Control System.

7. Hydraulic oil temperature is too low.

   1. Warm up the machine's hydraulic oil.