REDUCER 2W7766 - Caterpillar

Electronic Control Module (Hydrostatic Transmission)
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Electronic control module (ECM)The hydrostatic transmission electronic control module (ECM) makes decisions that are based on input information and memory information. After the hydrostatic transmission ECM receives the input information and memory information, the hydrostatic transmission ECM sends a corresponding response to the outputs. The inputs and outputs of the hydrostatic transmission ECM are connected to the machine harness by two 40 contact connectors (B and D). The ECM is located behind the large hinged access panel on the right side of the machine. There are no visual indicators on the ECM. Information from the Hydrostatic Transmission ECM is shown on the Caterpillar Monitoring System. The ECM sends the information to the Caterpillar Monitoring System on the CAT data link.Note: The ECM is not serviceable. The ECM must be replaced if the ECM is damaged. The ECM must be replaced if the ECM is diagnosed as being faulty.Inputs
The inputs describe the status of the machine systems. Two types of inputs exist. The inputs can be either a switch type or a sensor type. Switches provide an open, a ground, or a + battery signal to the inputs of the controller. Sensors (frequency, PWM or voltage) provide a changing signal to the sensor inputs of the controller.Outputs
The hydrostatic transmission ECM responds to decisions by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the hydrostatic transmission ECM.Input/Output
The data link is used in order to communicate with other electronic control modules on the machine. The data link is bidirectional. The ECM uses the data link for sending information and for receiving information. The data link allows the sharing of information with other electronic control modules. Travel Speed And Direction Function
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Travel speed and direction functionTravel speed and direction are determined by the position of the speed/direction control lever. The lever moves in an upside-down "Y" pattern. Movement of the lever to the right is FORWARD and movement of the lever to the left is REVERSE. The machine is in NEUTRAL when the speed/direction control lever is in the center part of the "Y" pattern. The parking brake is applied when the lever is in the tip of the upside-down "Y" pattern. The ECM sends current to the solenoids that correspond to the speed that is selected by the operator and to the direction that is selected by the operator. When the optional travel speed switch is placed in the Work Mode position, speed is reduced to 70 percent of the normal speed. Normal speed is the speed that results when the travel speed switch is placed in the Travel Mode position.Steering Function
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Right steering function (Right spot turn)Right pedal that is fully depressedThe ECM monitors the position of the left and right steering pedals. As a pedal is pressed, the ECM reduces the speed of the appropriate track which causes the machine to turn in the selected direction. When a steering pedal is pressed, the