DYNAMIC RADAR CRUISE CONTROL SYSTEM

FUNCTION OF MAIN COMPONENTS

The main components in the dynamic radar cruise control system have the following functions:

Component		Function
ECM		Controls the dynamic radar cruise control system in accordance with signals from switches, sensors, and the driving support ECU assembly. If the ECM detects a malfunction in the dynamic radar cruise control system, it will store Diagnostic Trouble Codes (DTCs).
Driving Support ECU Assembly		While the dynamic radar cruise control system is in vehicle-to-vehicle distance control mode, the driving support ECU assembly detects the vehicle ahead based on signals from the millimeter wave radar sensor assembly and forward recognition camera. Then, the driving support ECU assembly calculates the acceleration or deceleration rate required in order to attain the target vehicle-to-vehicle distance, and sends a request signal to the ECM. If the driving support ECU assembly detects a malfunction in the dynamic radar cruise control system, it will store Diagnostic Trouble Codes (DTCs).
Millimeter Wave Radar Sensor Assembly		Radiates millimeter radar waves forward, uses the reflected waves to detect the presence of a vehicle traveling ahead, the vehicle-to-vehicle distance and the relative speed, and then sends this information to the driving support ECU assembly.
Forward Recognition Camera		Acquires preceding vehicle and lane detection information from the built-in camera and sends signals to the driving support ECU assembly. Controls the supply of electric current to the camera heater when the ambient temperature is low.
Camera Heater (Forward Recognition Hood with Heater Sub-assembly)*1		Control is performed by the forward recognition camera to supply electric current and heat the heater, preventing the windshield glass in front of the forward recognition camera from fogging up.
Throttle Body with Motor Assembly*2	Throttle Control Motor	Adjusts the throttle valve opening angle in accordance with signals from the ECM.
Throttle Body with Motor Assembly*2	Throttle Position Sensor	Detects the throttle valve opening angle and sends it to the ECM.
Injector Assembly*3		Adjusts the fuel injection volume based on the signals from the ECM4 or the injector driver5.
Cruise Control Main Switch	ON-OFF/Mode Button	Turns the dynamic radar cruise control system on and off. Vehicle-to-vehicle distance control mode is activated immediately after the button is turned on. The mode is changed to constant speed control mode by pressing and holding the button for more than 1.5 seconds while the dynamic radar cruise control system is turned off.
	-SET Switch	The deceleration function and vehicle speed setting resume signals are sent to the ECM.
	+RES Switch	The acceleration function and resuming of a preset speed can be performed by operating this switch. A signal is sent to the ECM.
	CANCEL Switch	A cancel signal is sent to the ECM.
Steering Pad Switch Assembly	Vehicle-to-vehicle Distance Control Switch	While the dynamic radar cruise control system is in vehicle-to-vehicle distance control mode, the driver can operate the vehicle-to-vehicle distance control switch to select the vehicle-to-vehicle distance in three levels: long, middle and short.
Stop Light Switch Assembly		Detects brake pedal depression and sends its signal to the ECM.
Combination Meter Assembly	Multi-information Display	During cruise control operation, the multi-information display receives signals from the ECM in order to display the system conditions.
	Cruise Control Indicator (Constant Speed Control Mode)	Based on a cruise control indicator (constant speed control mode) operation signal sent by the ECM, the combination meter assembly illuminates the cruise control indicator (constant speed control mode) when the dynamic radar cruise control system in constant speed control mode has been turned on using the ON-OFF/mode button on the cruise control main switch. Based on a cruise control indicator (constant speed control mode) operation signal sent by the ECM or driving support ECU assembly, the combination meter assembly turns off the cruise control indicator light if a malfunction occurs in the dynamic radar cruise control system.
	Cruise Control Indicator (Vehicle-to-vehicle Distance Control Mode)	Based on a cruise control indicator (vehicle-to-vehicle distance control mode) operation signal sent by the ECM, the combination meter assembly illuminates the cruise control indicator (vehicle-to-vehicle distance control mode) when the dynamic radar cruise control system in vehicle-to-vehicle distance control mode has been turned on using the ON-OFF/mode button on the cruise control main switch. Based on a cruise control indicator (vehicle-to-vehicle distance control mode) operation signal sent by the ECM or driving support ECU assembly, the combination meter assembly turns off the cruise control indicator (vehicle-to-vehicle distance control mode) if a malfunction occurs in the dynamic radar cruise control system.
	Cruise Control SET Indicator	Illuminates when the vehicle speed is set.
	Master Warning Light	Comes on when there is a malfunction in the dynamic radar cruise control system.
	Meter Buzzer	If the ECM detects automatic cancel or warning signals while the vehicle is operating under cruise control, this buzzer sounds to inform the driver.
Steering Sensor		Detects the angle and direction of steering and sends signals to the driving support ECU assembly.
Airbag ECU Assembly		Detects the yaw rate of the vehicle and sends signals to the driving support ECU assembly.
Skid Control ECU		While the dynamic radar cruise control system is operating in vehicle-to-vehicle distance control mode, the skid control ECU operates the brake actuator assembly in accordance with the brake request signal received from the ECM. Sends a vehicle speed signal to the ECM. Sends the VSC and TRC control status to the ECM. Illuminates the stop lights during brake control.
4WD Control ECU		Sends cruise control system cancel request signals to the ECM.
Skid Control Buzzer Assembly		Sounds a buzzer when it receives a signal from the driving support ECU assembly to alert the driver that the distance between vehicles is short.
Accelerator Pedal Sensor Assembly		Detects the accelerator pedal depression degree and sends it to the ECM.
Injector Driver*5		Receives signals from the ECM to control the injector.
TCM*5		Controls the automatic transmission in accordance with signals from the ECM.
Central Gateway ECU (Network Gateway ECU)		Transmits the signal between the CAN communication buses.
DLC3		The Global TechStream (GTS) can be connected to read the Diagnostic Trouble Codes (DTCs) of malfunctions.

*1: Models with camera heater

*2: Models with gasoline engine

*3: Models with diesel engine

*4: Models with 1GD-FTV engine

*5: Models with 1KD-FTV engine

SYSTEM CONTROL
1. The driving support ECU assembly, millimeter wave radar sensor assembly, forward recognition camera and ECM control the dynamic radar cruise control system.
2. The combination meter assembly inform the driver of the control conditions.
3. For vehicles with the dynamic radar cruise control system, constant speed control mode is controlled by the ECM.
4. Vehicle-to-vehicle distance control mode is controlled by the millimeter wave radar sensor assembly, forward recognition camera and driving support ECU assembly. Thus, signals are sent to the actuators and the ECU while exchanging data as indicated below.

FUNCTION

Control of Dynamic Radar Cruise Control System Varies Depending on Mode

A: Constant speed control mode
B: Vehicle-to-vehicle distance control mode

Function	Outline	Mode
Function	Outline	A	B
Constant Speed Control	The ECM compares the actual vehicle speed and the set speed, and if the vehicle speed is lower than the set speed it accelerates the vehicle by adjusting the respective motive forces.	○	○
Constant Speed Control	The ECM compares the actual vehicle speed and the set speed, and if the vehicle speed is higher than the set speed it decelerates the vehicle by adjusting the respective motive forces.	○	○
Deceleration Control	Performs throttle control and brake control in order to decelerate the vehicle so that the vehicle-to-vehicle distance between the driver's own vehicle and the vehicle ahead is maintained at the set distance.	-	○
Follow-up Control	After performing deceleration control, the driver's own vehicle follows the vehicle ahead in order to maintain the proper vehicle-to-vehicle distance. The actual distance maintained for each distance level (long, medium and short) varies in accordance with the vehicle speed.	-	○
Acceleration Control	Accelerates the vehicle in order to attain the set vehicle speed if the vehicle ahead or the driver's own vehicle has changed lanes.	-	○
Set Control	When the dynamic radar cruise control system has been turned on using the ON-OFF/mode button on the cruise control main switch, either of the relevant vehicle speed conditions shown below is met, and the cruise control main switch is moved to the -SET side and released, the ECM stores the vehicle speed and maintains the vehicle constantly at that speed.	○	○
	The vehicle is traveling at a speed of approximately 40 km/h or more (25 mph or more).	○	-
	The vehicle is traveling at a speed of approximately 50 km/h or more (30 mph or more).	-	○
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 (25 mph). The dynamic radar cruise control system cannot be set below that speed. If the vehicle speed drops below that speed while driving using cruise control, speed control by the dynamic radar cruise control system will be canceled automatically. The set vehicle speed is kept in memory.	○	○
Coast Control	While the cruise control main switch is held to the -SET side, the vehicle speed and the set vehicle speed change as follows, according to the mode:	○	○
	The vehicle decelerates constantly. The set vehicle speed changes to the speed at which the -SET switch is released.	○	-
	The set vehicle speed decreases in increments of 5 km/h or 5 mph. [Example: 103 → 100 → 95 → 90 → 85 km/h (mph)] The vehicle decelerates rapidly. The vehicle will remain at the speed that the vehicle is traveling at when the -SET switch is released.	-	○
Tap-down Control	When the cruise control main switch is moved momentarily (approximately 0.6 seconds or less) to the -SET side, the vehicle speed and the set vehicle speed change as follows, according to the mode:	○	○
	The vehicle will decelerate in increments of approximately 1 km/h or 1 mph each time the -SET switch is pushed. However, if the difference between the actual vehicle speed and the set vehicle speed is greater than 5 km/h (3 mph), the set vehicle speed will change to the speed at which the vehicle was being driven at the time the -SET switch was operated.	○	-
	The vehicle will decelerate in increments of approximately 1 km/h or 1 mph for each time the -SET switch is pushed.1 The vehicle will decelerate in increments of approximately 5 km/h or 5 mph for each time the -SET switch is pushed.2	-	○
Accelerator Control	While the cruise control main switch is held to the +RES side, the vehicle speed and the set vehicle speed change as follows, according to the mode:	○	○
	The vehicle accelerates constantly. The set vehicle speed changes to the speed at which the +RES switch is released.	○	-
	The set vehicle speed increases in increments of 5 km/h or 5 mph. [Example: 83 → 85 → 90 → 95 → 100 km/h (mph)] The vehicle will accelerate to the speed that is set at the time the +RES switch is released. However, only the set vehicle speed will change during follow-up control.	-	○
Tap-up Control	When the cruise control main switch is moved momentarily (approximately 0.6 seconds or less) to the +RES side, the vehicle speed and the set vehicle speed change as follows:	○	○
	The vehicle will accelerate in increments of approximately 1 km/h or 1 mph for each time the +RES switch was pushed. However, if the difference between the actual vehicle speed and the set vehicle speed is greater than 5 km/h (3 mph), the set vehicle speed will not change.	○	-
	The vehicle will accelerate in increments of approximately 1 km/h or 1 mph for each time the +RES switch is pushed.1 The vehicle will accelerate in increments of approximately 5 km/h or 5 mph for each time the +RES switch is pushed.2	-	○
Shift-down Control	When the vehicle is traveling uphill using cruise control, automatic transaxle control may cause the transaxle to shift down. During shift down control, when the end of uphill travel is determined based on the throttle valve angle, the transaxle will shift up after a certain period of time. When the transaxle shifts down during accelerator control or resume control, the transaxle will shift up after accelerator control or resume control ends.	○	○
Resume Control	If the vehicle speed is above the low speed limit, the +RES switch can be pushed to resume cruise control operation and reach the vehicle speed that was set at the time the driver canceled cruise control.	○	○
Resume Control	If the vehicle ahead changes driving lanes during follow-up control, the vehicle speed is gradually increased to the set vehicle speed. At this time, the vehicle speed can be increased promptly by pushing the +RES switch.	-	○
Manual Cancel Control	If any of the following signals are sent to the ECM, the cruise control is canceled accordingly: Stop light switch assembly is turned on (brake pedal is depressed). Shift lever is moved from D or S to any other position. When the 1st, 2nd or 3rd range is selected in S position. ON-OFF/mode button off signal. CANCEL switch on signal (CANCEL switch on the cruise control main switch is pushed).	○	○
Automatic Cancel Control	When an automatic cancel signal is sent to the ECM, cruise control operation is canceled. At this time, the type of warning sent to the driver and the control resumption condition varies according to the cancel signal.	○	○
Mode Switching Control	The following operations switch modes: Vehicle-to-vehicle distance control mode is activated immediately after the ON-OFF/mode button is turned on. The mode is changed to constant speed control mode by pressing and holding the ON-OFF/mode button for more than 1.5 seconds while the dynamic radar cruise control system is turned off.	○	○
Other Control Cancellation Conditions	If any of the following conditions occur during cruise control driving, speed control by the dynamic radar cruise control system is canceled. However, the set speed remains in the memory: VSC operates during cruise control driving. TRC operates for a certain period of time during cruise control driving. TRC is off or VSC is off. Pre-collision system operates during cruise control driving. A cancel request is received from the 4WD control ECU.	○	○

*1: Except models for Europe

*2: Models for Europe

Tech Tips

○: Available

-: Not available

Constant Speed Control Mode
1. The ECM compares the set vehicle speed and the actual vehicle speed, and performs constant speed control in order to attain the set vehicle speed.
Vehicle-to-vehicle Distance Control Mode
- In vehicle-to-vehicle distance control mode, the ECM performs the deceleration control function, follow-up control function or acceleration control function based on the information about the vehicle ahead sent from the driving support ECU assembly, millimeter wave radar sensor assembly and forward recognition camera.
1. The millimeter wave radar sensor assembly and forward recognition camera send information about the vehicle ahead to the driving support ECU assembly and also send a millimeter wave radar sensor assembly operation signal to the ECM via the driving support ECU assembly. The ECM compares the set vehicle speed and the actual vehicle speed, and performs constant speed control in order to attain the set vehicle speed.
2. Deceleration Control Function
  - The driving support ECU assembly calculates the target deceleration rate in accordance with signals from the millimeter wave radar sensor assembly, forward recognition camera and sends a deceleration request signal to the ECM. Upon receiving this signal, the ECM performs throttle control and brake control in order to cause the vehicle to decelerate.
  - This control is not performed in the presence of a parked vehicle or object or below the settable vehicle speed range.
  - If the ECM determines that further deceleration is necessary, it sends a brake request signal to the skid control ECU. Upon receiving this signal, the skid control ECU then activates the brake actuator assembly to apply the brakes.
  - At this time, if the deceleration rate is higher than a predetermined value, the skid control ECU sends a stop light illumination request signal in order to inform anyone who might be following the vehicle.
  - If the vehicle is not decelerating adequately, the driving support ECU assembly sounds the skid control buzzer assembly. The buzzer is sounded to urge the driver to depress the brake pedal.
3. Follow-up Control Function
  - After performing deceleration control, the driving support ECU assembly sends request signals to the ECM so that the vehicle can follow the vehicle ahead while maintaining the proper vehicle-to-vehicle distance. The actual distance maintained for each distance level (long, middle and short) varies in accordance with the vehicle speed. Upon receiving these signals, these ECUs control the motive force in order to perform follow-up control.
  - 3 stages (long, middle and short) of vehicle-to-vehicle distance can be selected by operating the vehicle-to-vehicle distance control switch.
4. Acceleration Control Function
  - If the driving support ECU assembly detects that either the vehicle ahead or the driver's own vehicle has changed lanes, a request signal is sent to the ECM in order to attain the set vehicle speed. Upon receiving this signal, the ECM controls the motive force in order to perform acceleration control.

Automatic Cancel Control

If any of the conditions listed below occur while the vehicle is being driven using cruise control, speed control by the dynamic radar cruise control system will be canceled. Then, the following warning items will appear for the driver.

Constant Speed Control Mode
Description of Malfunction	Multi-information Display	Master Warning Light
If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. An open or short circuit in the stop light switch. Speed control by the dynamic radar cruise control system is disabled until the conditions are corrected or the dynamic radar cruise control system is turned off and back on again using the ON-OFF/mode button on the cruise control main switch.	Cruise Control Malfunction Visit Your Dealer	Illuminates
If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. Malfunction in the engine system Speed control by the dynamic radar cruise control system is disabled until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the ON-OFF/mode button on the cruise control main switch.	-	-
If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. The vehicle speed drops more than 16 km/h (10 mph) below the set vehicle speed.	-	-
If the condition listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory. The vehicle speed drops below the low speed limit [approximately 40 km/h (25 mph)].	-	-
If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. VSC operates during cruise control driving. TRC operates for a certain period of time during cruise control driving. TRC is off or VSC is off. Pre-collision system operates during cruise control driving. A cancel request is received from the 4WD control ECU.	-	-

Vehicle-to-vehicle Distance Control Mode
Description of Malfunction	Multi-information Display	Master Warning Light
If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. An open or short circuit in the stop light switch. Cruise control is prohibited until the normal operating conditions are met or the dynamic radar cruise control system is turned off and back on again using the ON-OFF/mode button on the cruise control main switch.	Cruise Control Malfunction Visit Your Dealer	Illuminates
If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. Malfunction of the millimeter wave radar sensor assembly. Misalignment of the axis of the millimeter wave radar sensor assembly. Malfunction in the dynamic radar cruise control system other than those given above. Speed control by the dynamic radar cruise control system is disabled until the ignition switch is turned on (IG) again.	Cruise Control Malfunction Visit Your Dealer	Illuminates
If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. Malfunction in the engine system Speed control by the dynamic radar cruise control system is prohibited until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the ON-OFF/mode button on the cruise control main switch.	-	-
If the condition listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory. The millimeter wave radar sensor assembly or the emblem is dirty. Speed control by the dynamic radar cruise control system is prohibited until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the ON-OFF/mode button on the cruise control main switch.	Radar Cruise Control Unavailable Clean Sensor	Illuminates
If either of the conditions listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory. The measurement becomes extremely unstable due to poor weather conditions. Brake control by the dynamic radar cruise control system is temporarily unavailable. The beam axis of millimeter wave radar sensor assembly misaligned. The forward recognition camera is temporarily unavailable. Speed control by the dynamic radar cruise control system is prohibited until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the ON-OFF/mode button on the cruise control main switch.	Radar Cruise Control Unavailable	Illuminates
If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system. VSC operates during cruise control driving. TRC operates for a certain period of time during cruise control driving. TRC is off or VSC is off. Pre-collision system operates during cruise control driving. A cancel request is received from the 4WD control ECU.	-	-
If the condition listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory. The vehicle speed drops below the low speed limit (approximately 40 km/h [25 mph]).	-	-

DIAGNOSIS
1. If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the ECM and driving support ECU assembly cancels cruise control operation, illuminates the master warning light and turns off the cruise control indicator (constant speed control mode/vehicle-to-vehicle distance control mode), and cruise SET indicator. Also, "Cruise Control Malfunction Visit Your Dealer" is displayed on the multi-information display to inform the driver of a malfunction. At the same time, the malfunction is stored in memory as a 5-digit Diagnostic Trouble Code (DTC).
2. The 5-digit DTC can be read by connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.