BUSHING 4664748 - Caterpillar

Machine ECM Switched Inputs
Inputs of the Starter Key Switch Inputs
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"Key Start" switch input connections to the Machine ECM and Engine ECM
The "Key Start" switch provides the voltage input to the Machine ECM. The Key Start Switch provides the voltage input to the Engine ECM.
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Key Start switch
When the "starter key" switch is moved to the ON position, a system voltage is provided to all of the control modules on the machine. The presence of this voltage input will cause each ECM to transition from the "sleep mode" (inactive) to the operational mode. When this occurs, each ECM will initialize and then become operational.When the "starter key" switch is moved to the OFF position, the system voltage is no longer present at the ECM "Key Switch - ON" input. The absence of the system voltage signals the ECM to transition from the operational mode to the sleep mode. The ECM will perform some internal power down procedures before entering the sleep mode.The period from the sleep mode to the operational mode happens in a very short period of time. When the "starter key" switch is moved to the "START" position, an input voltage will be provided to the start contact of the Machine ECM. When the ECM detects that the voltage in the circuit and the machine status for the system are correct, the ECM will initiate the engine cranking sequence. The key start switch circuits are not monitored for diagnostics by the Machine ECM.Park Brake Switch Inputs
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Park Brake switch input connections to the Machine ECM
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The Park Brake switch is located under the cover for the "Operator Left Control" handle.
The Park Brake switch is a two pole switch. One pole is used to provide two switch to ground inputs to the Machine ECM. The other pole is used to energize the Park Brake Solenoid.The ECM monitors the position of the switch in order to determine the status of the switch and to detect a change in the switch state. During machine operation, if the operator presses the Park Brake Switch in order to engage the parking brake, system power from the park brake solenoid fuse is passed through the switch contacts of the energize circuit to the Parking Brake solenoid. When the Parking Brake Solenoid is energized, the hydraulic oil in the brake system is directed to the hydraulic tank which will result in the parking brake being engaged.Under certain machine conditions, the Machine ECM can override the Park Brake Switch and energize the Park Brake Solenoid with an ON/OFF type output that is connected to the solenoid energize circuit.Autoshift Switch
Illustration 17 g01876515The autoshift switch or the Advisor informs the ECM that the operator wants the autoshift function to operate. The following selections can be made when the switch is activated sequentially:
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Location of "Autoshift" switch
The autoshift function can be turned ON and OFF with either the advisor or the switch (see above). The switch only toggles between ON and OFF.The following selections can be made only