TIRE 3803683 - Caterpillar

Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.
The "All Wheel Steer (AWS) Controller" is designed to control the switching between steering modes on a "Backhoe Loader - Side Shift (BHL-SS) 4WS" system. The ECU receives input from the machine operator in the form of digital signals from a 2WS/4WS switch and a "Circle/Crab" switch respectively. The ECU receives input from sensors that monitor the position of the front and rear axles to determine the alignment of the axles.Switching between two-wheel steer (2WS) and four-wheel steer (4WS) is dependent on the signal from the alignment sensors. When the machine is in 4WS mode, the operator can select either "Circle" or "Crab" operation. See 1 for the location of these controls, located to the right of the steering column. The auto-align controls the mode by activating/deactivating four solenoid valves which in turn control the hydraulic flow and hence the steering mode.
Illustration 1 g03737076
(1) "Circle/Crab Switch"
(2) "All Wheel Steer Switch" The primary purpose of the "Steering Control Module" is to control the switching between modes of steering operation. When the machine operator switches between steer modes, the system remains in the previously commanded mode until the axles align. The ECU then switches to the desired mode.At power ON, the controller reads the state of the inputs. The desired steering mode is immediately applied if the selected mode matches that of the last mode stored in non-volatile memory (NVM). After the bulb-test period the controller waits for the axles to align before switching to the selected mode, as per normal operation.When no previous mode is stored in NVM (factory initialized to NULL mode), the ECU immediately applies the mode selected by the input switches. The sensors check the wheel alignment for the mode selected. When the alignment is correct, the ECU will enter normal operation. If not, the selected LED for the mode blinks at the "Mode Change" blink rate. If the mode is changed before the wheels align, the LED for the selected mode will start blinking. Simultaneously, the LED for the first mode will still be activated.If first mode selected was incorrect because the wheels were not properly aligned, the operator must perform the following tasks:
Select the correct mode
Cycle the power to initialize the ECU
Align the wheels of the machineThe steering actuators hold the steering mode in position when the solenoids are not activated. This design reduces opportunities for leakage through the "Crab" or "Circle" coil while in 2WS mode. This leakage can affect the drift of the rear wheels on the machine. To reduce the leakage, one or the other of the "Crab/Circle" solenoids is engaged even while in 2WS mode. By default the "Circle" solenoid is engaged if the last mode stored in NVM was 2WS. When switching from 4WS to 2WS, the coil of the last active 4WS mode