System Description [11/2015 - ]

CRUISE CONTROL SYSTEM

This system is controlled by the hybrid vehicle control ECU, and control is performed using the throttle body with motor assembly and motor drive force. The hybrid vehicle control ECU controls the following functions: ON-OFF, - (COAST)/SET, + (ACCEL)/RES (RESUME), CANCEL and vehicle speed operation.

The hybrid vehicle control ECU compares the vehicle speed from the speed sensor with the stored vehicle speed set using the cruise control main switch. The hybrid vehicle control ECU instructs the throttle valve motor of the throttle with motor body assembly to close the valve and the motor generator to decrease the motor drive force when the vehicle speed is greater than the stored speed, and instructs the throttle valve motor to open the valve and the motor generator to increase the motor drive force when the vehicle speed is less than the stored speed.
The hybrid vehicle control ECU receives signals such as ON-OFF, - (COAST)/SET, + (ACCEL)/RES (RESUME), and CANCEL from the cruise control main switch and executes the command.
The hybrid vehicle control ECU illuminates the combination meter assembly cruise control indicator when the cruise control system is turned on using the cruise control main switch (ON-OFF button).
The hybrid vehicle control ECU turns off the combination meter assembly cruise control indicator and displays a warning message when a malfunction occurs during cruise control driving.

The hybrid vehicle control ECU illuminates the combination meter assembly cruise control SET indicator when vehicle speed control begins after the cruise control main switch is pushed to -SET while driving.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Cruise Control Indicator
*b	Cruise Control SET Indicator

FUNCTION OF MAIN COMPONENTS

The main components of the cruise control system have the following functions:

Component		Function
Cruise Control Main Switch	ON-OFF Button	Turns the cruise control system on and off.
	CANCEL Switch	A cancel signal is sent to the hybrid vehicle control ECU when the switch is operated.
	+RES Switch	Acceleration and stored speed resume signals are sent to the hybrid vehicle control ECU when the switch is operated.
	-SET Switch	Deceleration and vehicle speed setting signals are sent to the hybrid vehicle control ECU when the switch is operated.
Skid Control ECU (Brake Booster with Master Cylinder Assembly)		Sends VSC operation signals to the hybrid vehicle control ECU. Sends TRC operation signals to the hybrid vehicle control ECU. Sends signals such as wheel speed and estimated vehicle acceleration signals to the hybrid vehicle control ECU.
Hybrid Vehicle Control ECU		Controls all functions of the cruise control system in accordance with the signals received from switches, sensors and ECUs.
Combination Meter Assembly	Cruise Control Indicator	Illuminates based on signals from the hybrid vehicle control ECU when the cruise control system is turned on using the cruise control main switch (ON-OFF button). Turns off based on signals from the hybrid vehicle control ECU when a malfunction is detected in the cruise control system.
	Cruise Control SET Indicator	Illuminates when the vehicle speed is set.
	Multi-information Display	Displays warning messages to alert the driver. The set speed will be displayed in the multi-information display.
Throttle Body Assembly	Throttle Control Motor	Adjusts the throttle valve opening angle in accordance with signals received from the hybrid vehicle control ECU.
Throttle Body Assembly	Throttle Position Sensor	Outputs the throttle valve opening angle to the hybrid vehicle control ECU.
Speed Sensor		Outputs wheel speed signals to the skid control ECU (brake booster with master cylinder assembly).
Accelerator Pedal Sensor Assembly		Outputs accelerator pedal depression angle to the hybrid vehicle control ECU.
VSC OFF Switch		Outputs VSC off signals to the skid control ECU (brake booster with master cylinder assembly).
Shift Lock Control Unit Assembly	Shift Sensor	Outputs the shift sensor signals to the hybrid vehicle control ECU.
Stop Light Switch Assembly		Outputs brake pedal depressed signals to the hybrid vehicle control ECU.

OPERATION OF CRUISE CONTROL

The cruise control system has the following control functions:

Function	Outline
Constant Speed Control	The hybrid vehicle control ECU compares the actual vehicle speed and the set speed and if the vehicle speed is less than the set speed, it uses the throttle control motor to increase the throttle valve opening angle.
Set Control	The vehicle speed is stored and speed control is performed when the cruise control main switch is pushed to -SET while driving with the cruise control system on, and the vehicle speed is within the set speed range.
Low Speed Limit Control	The low speed limit is the lowest speed that cruise control can be set at and it is designed to be approximately 40 km/h or 25 mph. The cruise control system cannot be set below that speed. If the vehicle speed drops below that speed while the cruise control is operating, speed control by the cruise control system will be canceled automatically. However, the set speed is kept in memory.
High Speed Limit Control	The highest possible set speed is approximately 200 km/h or 125 mph. The cruise control system cannot be set when the vehicle speed is over the high speed limit. Also, + (ACCEL)/RES (RESUME) cannot be used to increase the speed beyond the high speed limit.
- (COAST) Control	When the cruise control system is controlling vehicle speed and the cruise control main switch is pushed to -SET and held in that position, the cruise control system sends a "throttle valve opening angle 0°" demand signal to the hybrid vehicle control ECU. Following this, the vehicle speed is stored and maintained when the cruise control main switch is released.
Tap-down Control	When the cruise control system is controlling vehicle speed and the cruise control main switch is tapped to -SET (for approximately 0.6 seconds), the stored vehicle speed decreases by approximately 1 km/h or 1 mph for each time the switch is tapped. When the cruise control main switch is tapped to -SET and the difference between the current and stored vehicle speed is more than 5 km/h or 3 mph, the current vehicle speed is stored and speed control is performed.
+ (ACCEL) Control	When the cruise control system is controlling vehicle speed and the cruise control main switch is pushed to +RES and held in that position, the cruise control system sends a signal to the hybrid vehicle control ECU to operate the throttle valve motor of the throttle body with motor assembly to open the throttle valve. Following this, the vehicle speed is stored and maintained when the cruise control main switch is released.
Tap-up Control	When the cruise control system is controlling vehicle speed and the cruise control main switch is tapped to +RES (for approximately 0.6 seconds), the stored vehicle speed increases by approximately 1 km/h or 1 mph for each time the switch is tapped. When the cruise control main switch is tapped to +RES and the difference between the current and stored vehicle speed is more than 5 km/h or 3 mph, the stored vehicle speed will not be changed.
RES (Resume) Control	If control of vehicle speed by the cruise control system was canceled due to any of the manual cancel conditions (other than turning the cruise control system off using the cruise control main switch (ON-OFF button)), and if the vehicle speed is between the low and high speed limits, the stored vehicle speed from the time of cancellation will be resumed and maintained when the cruise control main switch is pushed to +RES.
Manual Cancel Control	Performing any of the following cancels the cruise control system control of vehicle speed (the stored vehicle speed in the hybrid vehicle control ECU is maintained). Depressing the brake pedal. Moving the shift lever from D to any other position. Pulling the cruise control main switch to CANCEL. Turning the cruise control system off using the cruise control main switch (ON-OFF button) (the stored vehicle speed in the hybrid vehicle control ECU is not maintained).
Automatic Cancel Control	This system has an automatic cancellation function (fail-safe). Refer to FAIL-SAFE CHART [11/2015 - ]