CYLINDER & MTG GP-BLADE LIFT 8X1948 - Caterpillar

Transmission Pilot Supply Solenoid
The transmission pilot supply solenoid provides hydraulic pilot oil to the hydrostatic pumps, as well as the parking brake solenoid. The ECM only energizes the transmission pilot supply solenoid if the neutral interlock has been cleared. If the transmission pilot supply solenoid is de-energized, machine cannot be moved and the parking brake is applied. The ECM also de-energizes this solenoid during a fault that requires the transmission to shut down.Solenoid Valves (Pump and Motor Displacement Control)
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Forward solenoid for the left drive pump Reverse solenoid for the left drive pumpReverse solenoid for the right drive pumpForward solenoid for the right drive pumpProportional solenoid of the right drive motorProportional solenoid of the left drive motorThe four solenoid valves for the drive pumps are outputs of the ECM. The ECM uses these solenoid valves to control the speed and the direction of the machine by varying the pump displacements. The two solenoid valves for the drive motors are outputs of the ECM. The ECM uses these solenoid valves to control the machine speed by varying the motor displacements. The ECM applies electrical current to the appropriate solenoid valves based on the information from the following devices:
The Joystick forward/neutral/reverse position
The Joystick thumb wheel position
The Joystick steering position status
The Parking brake switch
The Engine speed sensor
The Left track speed Sensor
The Right track speed sensor
The Brake/Decel pedal
Traction assist switchThe solenoid valves are proportional pressure reducing valves. The ECM uses a pulse width modulated signal (PWM) to vary the current to the solenoid. The current varies the pressure output of the solenoid valve. The amount of pressure controls the swashplate angle of the pumps and motors.Backup Alarm
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Backup AlarmThe backup alarm is an output of the ECM. The backup alarm alerts nearby personnel that the machine is backing up. When the operator selects the REVERSE position, the ECM energizes the backup alarm.Power Pitch Relay
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The power pitch system energizes a relay that activates a diverter valve to divert hydraulic pressure from the tilt function to the pitch function. The ECM sends a signal to the power pitch relay in addition to the corresponding blade tilt solenoids.Solenoids
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Blade angle left solenoidBlade angle right solenoidBlade raise solenoidBlade lower solenoidBlade tilt left solenoidBlade tilt right solenoidImplement lockout solenoid
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Winch reel in solenoidWinch reel out solenoidAuxiliary one port A solenoidAuxiliary one port B solenoid
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Winch free spool solenoidWinch drive away solenoid
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Winch brake solenoidThe solenoid coils are not designed to operate using 12 DCV directly. The ECM sends a PWM signal of 12 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically.Note: A source of 12 DCV should be used, if the coils must be activated by not using the ECM.