FILM GP 1400035 - Caterpillar

Power Distribution
Illustration 1 g03412866
Steering Electrical Schematic
(1) From engine ECM fuse
(2) From machine ECM "1" fuse
(3) From propel/steer fuse
(4) Hydraulic temperature sender
(5) Steering encoder
(6) Steering angle position sensor
(7) Front counterclockwise solenoid
(8) Front clockwise solenoid
(9) Steering shunt solenoid
(10) Warm up valve solenoid
(11) Machine ECM number-one
(12) Engine ECM When the electrical disconnect switch is in the ON position, power transfers from engine ECM fuse (1) to the following terminals of engine ECM (12): "J1-7", "J1-8", "J1-15" and "J1-16". This voltage provides the main power source for the engine ECM. The engine ECM is grounded at the following terminals: "J1-1", "J1-2", "J1-3", "J1-9" and "J1-10".When the engine start switch is in the ON position, the machine ECM "1" fuse is energized. Power transfers from machine ECM "1" fuse (2) to the following terminals of machine ECM number-one (10): "2", "47", "48", "49" and "50". This voltage provides the main power source for the machine ECM and also provides the wake-up signal. The machine ECM is grounded at terminal "1".CAN Communication
Engine ECM (12) and machine ECM number-one (11) communicate through the CAN lines.Steering Shunt Solenoid
Steering shunt solenoid (9) is energized when the steering system is enabled or when the warm-up valve is energized.Steering shunt solenoid (9) enables and disables the steering system. When this solenoid is energized, the steering shunt valve is closed and oil from the steering pump is routed to the steering control valve. In this case, the steering system is enabled. When the solenoid is de-energized, the steering shunt valve opens and hydraulic oil from the steering pump is sent directly to the hydraulic tank. In this case, the steering system is disabled. The steering shunt solenoid receives power from terminal "32" of the machine ECM number-one.If the steering system detects motion without an active steering command, an uncommanded movement detection (UCMD) fault is logged. Also, if the steering system detects motion that is opposite the commanded direction, a UCMD fault is logged. In either case, the steering system, propel system, and vibratory system are disabled.Steering Controls
The steering system is a closed loop system that is position controlled. Steering angle position sensor (6) measures the angle of machine articulation and transmits this information to terminal "25" of machine ECM number-one (11).Machine ECM number-one (11) monitors the signals from the two steering sensors in steering encoder (5). The ECM counts the signal pulses and compares the phases of the signals to determine the position and direction of rotation of the steering wheel.Steering is controlled by a solenoid-controlled steering valve. Front clockwise solenoid (8) causes the machine to turn right. Front counterclockwise solenoid (7) causes the machine to turn left.Machine ECM number-one (11) monitors inputs from steering angle position sensor (6) and steering encoder (5). Based on these inputs, the machine ECM number-one sends signals to front counterclockwise solenoid (7) or front clockwise solenoid (8).Steering encoder (5) includes an electronically controlled friction device to control the force required to turn the steering wheel. Machine ECM number-one (11) transmits a signal to control the