PLATE 4777930 - Caterpillar

Features
Parking Brake Interlock
The interlock prevents the machine from accidental movement. The feature also prevents the operator from accidentally driving through the parking brake. The transmission will not shift to first gear forward or the transmission will not shift to first gear reverse when the parking brake is engaged. The ECM shifts the transmission to the NEUTRAL position when the transmission is in a gear and the parking brake is set. The transmission will not shift to a gear when the parking brake is released. The transmission must first be shifted to NEUTRAL in order to shift to a gear.Driving through the Parking Brake
This feature provides the capability to shift to first gear when the parking brake is engaged. The parking brake is engaged and the plunger that is in the cab pops out if the pressure for releasing the parking brake is not available. The operator can drive through the parking brake for a short distance. Hold the parking brake switch that is located in the cab in the OFF position. The switch contains a spring in order to resist this effort. This switch will automatically move to the ON position when the switch is released. Move the direction switch in the forward position or the reverse position. Do not release the parking brake switch. The transmission will shift to the respective gear. See table1 for more information.
Table 1
State STIC control Parking Brake Switch Parking Brake Transmission Gear Display
Initial "1F" OFF OFF "1F" "1F"
Brake ON failure "1F" ON ON "1N" "1N"
Direction to Neutral "1F" ON ON "1N" "1N"
Switch in OFF "1N" OFF ON "1N" "1N"
Direction to Forward or Reverse "1F" or "1R" OFF ON "1F" or "1R" "1F" or "1R" Parking Brake
Illustration 1 g01478268The operator uses the parking brake switch in order to set the brake. The ECM sets the brake if the operating conditions of the machine are appropriate. The ECM will log a diagnostic code of CID 0070 for the switch.
Table 2
Switch Status
Switch Position Normally Open Normally Closed
Out Closed Open
In Open Closed Parking Brake Pressure
Illustration 2 g01478277The parking brake pressure switch provides the ECM with information about the hydraulic portion of the parking brake assembly. The parking brake is applied by a spring. The parking brake is released by hydraulic pressure. The parking brake is on when the pressure switch is not actuated. The parking brake is off when the pressure switch is actuated. The ECM will log a diagnostic code of CID 0627 for the switch.
Table 3
Switch Status
Switch Position Normally Open Normally Closed
High Pressure Closed Open
Low Pressure Open Closed Position of Torque Converter Pedal
Illustration 3 g01478288The pedal position sensor determines the position of the torque converter pedal. The sensor sends a PWM signal to the ECM. The ECM monitors the signal. Then, the ECM calculates the position of the pedal from the signal. Information about the transmission output speed is broadcast on the Cat data link. The ECM will log a diagnostic code of CID 1712 for the torque converter pedal position sensor.Torque Converter Lockup Clutch Solenoid (Attachment)
Illustration