CRUISE CONTROL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components in 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 output to the ECM when this switch is operated.
      +RES Switch Acceleration and resuming of a preset speed can be performed by operating this switch. A signal is output to the ECM when this switch is operated.
      -SET Switch Deceleration function is operated and vehicle speed setting signals are output to the ECM when this switch is operated.
      ECM Controls the cruise control system in accordance with signals from the switches, sensors and skid control ECU.
      Throttle Body with Motor Assembly*1 Throttle Control Motor Adjusts the throttle valve opening angle in accordance with signals from the ECM.
      Throttle Position Sensor Detects the throttle valve opening angle and outputs it to the ECM.
      Injector Assembly*2 Adjusts the fuel injection volume based on the signals from the ECM*3 or the injector driver*4.
      Stop Light Switch Assembly Detects the depression of the brake pedal and transmits a signal to the ECM.
      Park/Neutral Position Switch Assembly*5 Detects the shift lever position and transmits a signal to the ECM.
      Clutch Switch Assembly*6 Detects depression of the clutch pedal and transmits a signal to the ECM.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression degree and outputs it to the ECM.
      Skid Control ECU Sends the vehicle speed signal to the ECM.
      4 Wheel Drive Control ECU*7 Sends cruise control system cancel request signals to the ECM.
      Transmission Floor Shift Assembly*5 Transmission Control Switch While the vehicle is being driven in S mode, this switch outputs a signal to the ECM when the shift lever is moved toward "+" or "-".
      Combination Meter Assembly Cruise Control Indicator Light

      • Based on a cruise control indicator light operation signal sent by the ECM, the combination meter assembly illuminates the cruise control indicator light when the cruise control system has been turned on using the ON-OFF button on the cruise control main switch.

      • Based on a cruise control indicator light operation signal sent by the ECM, the combination meter assembly turns off the cruise control indicator light *8 or the combination meter assembly turns the cruise control indicator light in yellow*9 if a malfunction occurs in the cruise control system.
      Cruise Control SET Indicator Light Illuminates when the vehicle speed is set.
      Multi-information Display*8 Displays a warning message to alert the driver in accordance with a signal sent by the ECM.
      Injector Driver*4 Receives signals from the ECM to control the injector.
      TCM*4 Controls the automatic transmission in accordance with signals from the ECM.

      *1: Models with gasoline engine

      *2: Models with diesel engine

      *3: Models with 1GD-FTV engine or 2GD-FTV engine

      *4: Models with 1KD-FTV engine

      *5: Models with automatic transmission

      *6: Models with manual transmission

      *7: 2WD models with rear differential lock system or 4WD models

      *8: Models with multi-information display

      *9: Models without multi-information display

  2. FUNCTION


    1. The cruise control system has the following functions:

      Function Outline
      Constant Speed Control Diesel Engine The ECM compares the actual vehicle speed and the set speed. If the vehicle speed is higher than the set speed, the ECM outputs a signal to reduce fuel injection volume. If the actual vehicle speed is lower than the set speed, the ECM outputs a signal to increase fuel injection volume.
      Gasoline Engine The ECM compares the actual vehicle speed and the set speed. If the vehicle speed is higher than the set speed, the ECM uses the throttle control motor to decrease the throttle opening. If the actual vehicle speed is lower than the set speed, the ECM uses the throttle control motor to increase the throttle opening.
      Set Control When the ON-OFF button is turned on and the cruise control main switch is pressed to the -SET direction and released, the ECM stores the vehicle speed in the memory and continues to control the vehicle at that speed. The set speed is between approx. 40 km/h (25 mph) and 200 km/h (125 mph). Furthermore, when the cruise control system is running, the cruise control SET indicator light on the combination meter assembly illuminates.
      Coast Control Diesel Engine When the cruise control main switch is kept pushed to the -SET direction while the cruise control system is running, the ECM decreases the fuel injection volume by regulating the 4 injectors. As the vehicle continues to decelerate, the ECM stores the vehicle speed at the time the cruise control main switch is released. From then on, the ECM continues to control the vehicle at that speed.
      Gasoline Engine When the cruise control main switch is kept pushed to the -SET direction while the cruise control system is running, the throttle control motor is energized in the throttle closing direction, and the vehicle keeps decelerating. The ECM stores the vehicle speed when the cruise control main switch is released. From then on, the ECM controls the vehicle speed at that speed constantly.
      Tap-down Control When the difference between the actual vehicle speed and the set speed is less than 5 km/h (3 mph), the set speed can be lowered approx. 1.6 km/h (1 mph) each time by operating the cruise control main switch in the -SET direction quickly within approx. 0.6 seconds.
      Accelerator Control Diesel Engine When the cruise control main switch is kept pushed to the +RES side while the cruise control system is running, the ECM increases the fuel injection volume by regulating the 4 injectors. The vehicle keeps accelerating and the ECM stores the vehicle speed when the cruise control main switch is released. From then on, the ECM continues to control the vehicle at that speed.
      Gasoline Engine When the cruise control main switch is kept pushed to the +RES side while the cruise control system is running, the throttle control motor is energized in the throttle opening direction. The vehicle keeps accelerating and the ECM stores the vehicle speed when the cruise control main switch is released. From then on, the ECM continues to control the vehicle at that speed.
      Tap-up Control When the difference between the actual vehicle speed and the set speed is less than 5 km/h (3 mph), the set speed can be increased approx. 1.6 km/h (1 mph) each time by operating the cruise control main switch in the +RES direction quickly within approx. 0.6 seconds.
      Low Speed Limit Control The low speed limit is the lowest speed that the cruise control system can be set to and is set at approx. 40 km/h (25 mph). The cruise control system cannot be set below that speed. If the vehicle speed drops below that speed while the cruise control system is running, the cruise control system is canceled automatically. However, the set vehicle speed in the memory is kept.
      Resume Control If the vehicle speed is above the low speed limit and the cruise control main switch is subsequently pushed to the +RES side, the cruise control resumes operation to reach the vehicle speed that was set at the time the driver canceled cruise control.
      Shift Down Control*1 When the vehicle is traveling uphill using cruise control, automatic transmission control may cause the transmission to shift down. During shift down control, when the end of uphill travel is determined, the transmission will shift up after a certain period of time. When the transmission shifts down during accelerator control or resume control, the transmission will shift up after accelerator control or the resume control ends.
      Manual Cancel Control

      If any of the following conditions is met, the cruise control is canceled accordingly. However, the set speed remains in the memory:


      • On signal is sent from the stop light switch assembly (the brake pedal is depressed).

      • Off signal is sent from the clutch switch assembly (the clutch pedal is depressed).*2

      • Shift lever is moved from D or S to other position.*1

      • S1, S2 or S3 range is selected.*1

      • On signal is sent from the CANCEL switch.

      • ON-OFF button is turned off (the set speed is not stored).

      • 4 wheel drive control ECU requests to cancel cruise control system.*3
      Automatic Cancel Control

      • When any of the following conditions occurs while the cruise control system is running, the set speed in the memory is cleared to cancel the cruise control system. Furthermore, for models with a multi-information display, the cruise control indicator light turns off and a malfunction notification is displayed on the multi-information display until the ON-OFF button is turned off. For models without a multi-information display, the cruise control indicator light illuminates yellow until the ON-OFF button is turned off. The operation of the cruise control is disabled until the cruise control system is turned on again using the ON-OFF button.


        • Stop light switch assembly has a open or short circuit.

        • Vehicle speed signals are abnormal.

      • When any of the following conditions occurs while the cruise control system is running, the set speed in the memory is cleared to cancel the cruise control system. Furthermore, the operation of the cruise control system is disabled until the ON-OFF button is turned on again.


        • The ETCS-i has a malfunction.*4

        • The common-rail type ECD system has a malfunction.*5

      • When any of the following conditions occurs while the cruise control system is running, the set speed in the memory is cleared to cancel the cruise control system. Furthermore, for models with a multi-information display, the cruise control indicator light turns off and a malfunction notification is displayed on the multi-information display until the ON-OFF button is turned off. For models without a multi-information display, the cruise control indicator light illuminates yellow until the ON-OFF button is turned off. The operation of the cruise control is disabled until the ignition switch is turned off.


        • The stop light switch assembly input signal is abnormal.

        • The cancel circuit has a malfunction.

        • There is a malfunction in the brake system

        • There is a communication malfunction between the skid control ECU and ECM.

      • If the following condition occurs during cruise control speed control operation, the speed that is set in memory is cleared and cruise control speed control operation is canceled.


        • Vehicle speed decreases by 16 km/h (10 mph) or more below the speed at which the cruise control is set.

      • If the following condition occurs during cruise control speed control operation, cruise control speed control operation is canceled.


        • Vehicle speed decreases below the low speed limit, which is approx. 40 km/h (25 mph).
      Other Control

      • If any of the following conditions occur during cruise control driving, the cruise control is canceled. However, the set speed remains in the memory.


        • VSC is activated.*6

        • TRC is activated for a period of time.*6

        • The VSC or TRC system is turned off by pressing the VSC OFF switch.*6

        • 4 wheel drive control ECU requests to cancel the cruise control system.*3

      • When the ignition switch is turned off, the set speed is not stored in the memory.

      *1: Models with automatic transmission

      *2: Models with manual transmission

      *3: 2WD models with rear differential lock system or 4WD models

      *4: Models with gasoline engine

      *5: Models with diesel engine

      *6: Models with VSC

  3. DIAGNOSIS


    1. If a malfunction occurs in the cruise control system during cruise control operation, the ECM cancels cruise control operation, illuminates the master warning light and turns off the cruise control indicator light and cruise control SET indicator light. At this time, a warning message is displayed on the multi-information display. The ECM stores the malfunction in the form of a 5-digit Diagnostic Trouble Code (DTC).*1

    2. If a malfunction occurs in the cruise control system during cruise control operation, the ECM cancels cruise control operation, illuminates the cruise control indicator light in yellow. The ECM stores the malfunction in the form of a 5-digit Diagnostic Trouble Code (DTC).*2

    3. The 5-digit DTC can be read by connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.


      • *1: Models with multi-information display

      • *2: Models without multi-information display