System Outline

The cruise control system is a constant vehicle speed controller which controls the opening angle of the engine throttle valve by the SW, and allows driving at a constant speed without depressing the accelerator pedal.

1. Set Control -  When the SET/COAST SW, see Fig 1, is operated while travelling with the main SW, see Fig 2 on, the speed when the SET/COAST SW is operated to off is memorized, and the vehicle speed is controlled at that speed.
2. Coast Control -  When the SET/COAST SW, see Fig 1, is operated to on, the motor in the actuator rotates the throttle valve until it is closed fully to decrease the vehicle speed, and the speed when the SET/COAST SW is operated to off is memorized, and the vehicle speed is controlled at that speed.

   Furthermore, every time the SET/COAST SW is operated momentarily (Approx. 0.5 sec.) to on, the memorized vehicle speed is decreased approximately 1.0 mph.

3. Accel Control -  When the RES/ACC SW, see Fig 3, is operated to on, the motor in the actuator rotates the throttle valve to open direction to increase the vehicle speed, and the speed when the RES/ACC SW, is operated to off is memorized, and the vehicle speed is controlled at that speed.

   Furthermore, every time the RES/ACC SW is operated momentarily (Approx. 0.5 sec.) to on the memorized vehicle speed is increased approximately 1.0 mph.

4. Manual Cancelling Mechanism -  If any of the following signals are input during cruise control traveling, the current to the motor flows in the direction to close the throttle valve, and cancel the cruise control.
   • The stop lamp SW is on (Brake pedal is depressed).
   • The CANCEL SW of the control SW is on.
   • The CRUISE SW is off.
   • Clutch SW is turned off from on (Clutch pedal is depressed).
5. Resume Control -  After cancelling the cruise control (except when the main SW is off) if the vehicle speed is above the minimum speed limit Approx. 25 mph operating the RES/ACC SW, see Fig 3, to on from off will cause the system to accelerate and resume to the vehicle speed before manual cancellation.
6. Overdrive Control Function -  The overdrive may be cut on an uphill grade, while travelling with the cruise control.

   After the overdrive is cut, if the vehicle speed reaches the overdrive resume speed (Set speed minus 1.2 mph) and if the system determines that the uphill grade has finished, the overdrive will resume after the overdrive timer operation.

7. Auto Cancel Operation -  If any of the following conditions are detected, the set speed is erased and the control is cancelled.
   • An open or short circuit in the motor circuit.
   • The motor does not operate.
   • Short in the magnetic clutch.
   • Disconnection in the magnetic clutch (includes blown stop lamp fuse).
   • No vehicle speed signal input.
   • The actual vehicle speed becomes slower than the minimum speed limit.
   • The actual vehicle speed becomes 10 mph slower than the set speed.

Fig 1: Identifying Set/Coast Setting

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002