CLAMP AS 1238253 - Caterpillar

Illustration 1 g03583674
(1) Stick drift reduction solenoid valve
(2) Boom drift reduction solenoid valve There are two Drift Reduction Valves (DRV) located on the ACS main control valve. The DRVs are located on the stick RE work port and the boom HE work port. The DRVs are checks that are opened and closed by the DRV solenoids. When the system is stationary, the DRVs have zero current commanded to the valve. When there is a stick in joystick command provided, a current is sent to the stick DRV. When there is a boom down joystick command provided, a current is sent to the boom DRV. There is not a modulated signal to the DRVs (The system is ON/OFF). The following procedure can be used to troubleshoot the DRV:
Verify that the main relief is properly set. If the valve is out of specification, adjust to the proper setting. Refer to Testing and Adjusting, KENR9615, "Relief Valve (Main) - Test and Adjust".
Calibrate the joysticks. If a joystick fails to calibrate, troubleshoot the joystick issue. Refer to Testing and Adjusting, KENR9615, "Joystick and Pedal - Calibrate"
Run the Bypass and the IMV calibrations. Refer to Testing and Adjusting, KENR9615, "Main Control Valve - Calibrate" and Troubleshooting, "IMV Calibration - Functional Test".
Check the boom down speed to determine if the boom DRV is opening.
Check the boom down cycle time and compare to Testing and Adjusting, KENR9615, "Cylinder Speed - Check".
If the boom down cycle time falls within the specifications, there is likely not an issue with the DRV
If the boom down cycle time is slow there may be an issue with the DRV. Proceed to test step 6.
Check the stick in speed to determine if the stick DRV is opening.
Check the stick in cycle time and compare to Testing and Adjusting, KENR9615, "Cylinder Speed - Check".
If the stick in cycle time falls within specifications, there is likely not an issue with the stick DRV.
If the stick in cycle time is slow there may be an issue with the DRV. A slow speed may be caused by other components.
While monitoring stick RE pressure in monitor, if stick RE pressure goes above 35 MPa (5076 psi) during stick in there is likely and issue with the stick DRV not opening.
If the boom DRV is suspected to be malfunctioning from test step 4 above, verify that voltage is being sent to the boom DRV solenoid.
Shut off the engine by turning the start switch to the "OFF" position. Ground the implements and perform System Pressure Release procedure. Refer to Testing and Adjusting, KENR9615, "System Pressure - Release". Insert the probes spoon lead into the Boom DRV solenoid connector. Use long leads to the multimeter to allow the reading to be monitored from a safe position.
Turn the key start switch to the "ON" position. The monitor is on but the engine is not running.
Place the hydraulic lockout in the "UNLOCKED" position.
Command a boom down while monitoring the boom DRV solenoid voltage from a safe position. For boom down, 24 V