STOP AND START


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Engine Stop and Start ECU Sends either an engine stop or restart signal to the ECM according to the signals from each sensor and switch.
    Engine Stop and Start ECU Backup Boost Converter Supplies battery voltage to help make up for the voltage drop that occurs when the engine is restarted, preventing the operation of various systems from being interrupted due to low battery voltage.
    External Backup Boost Converter (Eco Run Vehicle Converter Assembly)* Supplements the voltage drop when the engine is stopped to stabilize the audio output.
    Park/Neutral Position Switch Assembly Detects whether the shift lever position is in park/neutral and sends a signal to the engine stop and start ECU.
    Ambient Temperature Sensor (Thermistor Assembly) Sends the outside temperature signal and engine restart signal to the engine stop and start ECU.
    Vacuum Sensor Assembly Detects the brake booster vacuum pressure and sends a signal to the engine stop and start ECU.
    Hood Lock Assembly Engine Hood Courtesy Switch Detects whether the hood is open or closed and sends a signal to the engine stop and start ECU.
    Front Door Courtesy Light Switch Assembly (Driver) Detects whether the driver door is open or closed and sends a signal to the engine stop and start ECU via the main body ECU (multiplex network body ECU) via CAN communication.
    Front Seat Inner Belt Assembly (Driver) Front Seat Belt Buckle Switch (Driver) Detects whether or not the driver's seat belt has been fastened, and sends a signal to the engine stop and start ECU via the main body ECU (multiplex network body ECU) via CAN communication.
    Battery State Sensor Assembly Detects the battery charging and discharging amount and sends a signal to the ECM.
    Stop Light Switch Assembly Detects a brake pedal released condition and sends a signal to the engine stop and start ECU via the ECM.
    Accelerator Pedal Sensor Assembly Detects an accelerator pedal opening angle and sends a signal to the engine stop and start ECU via the ECM.
    Air Conditioning Amplifier Assembly Sends air conditioner operation signals and engine ON request signals to the engine stop and start ECU.
    Combination Meter Assembly Stop and Start Indicator Light

    • Turns on when the engine is stopped due to stop and start control.

    • Blinks to inform the driver that the idling stop is canceled and the engine will restart when the driver door is opened with the shift lever in D during idling stop.
    Stop and Start Cancel Indicator Light

    • Turns on to inform the driver that the system has been disabled when stop and start system operation is prohibited by the stop and start system cancel switch (combination switch assembly).

    • If a system malfunction is detected, the stop and start cancel indicator light blinks to inform the driver.
    Multi-information Display

    • Displays the amount of time idling stop was performed since the engine switch was turned on (IG) to when the engine switch was turned off and the amount of time idling stop was performed since the reset switch was last pressed.

    • Displays the settings of the stop and start system or warning information, etc.
    Combination Switch Assembly Stop and Start System Cancel Switch Operation of the system can be canceled by pressing the stop and start system cancel switch (combination switch assembly). Pressing the switch again or turning the power source off and back on restores the operation of the system.
    ECM

    • Sends various information about engine conditions to the engine stop and start ECU.

    • Based on signals from the battery state sensor assembly, determines whether the battery installed on the vehicle is a specified or non-specified battery, and sends the determination result to the engine stop and start ECU.
    Brake Actuator Assembly Skid Control ECU Sends a vehicle speed signal to the engine stop and start ECU.
    Airbag ECU Assembly Sends airbag deployment information in the event of a collision and a deceleration signal to the engine stop and start ECU.
    Main Body ECU (Multiplex Network Body ECU) Sends a front door courtesy light switch assembly signal and front seat belt buckle switch (driver) signal to the engine stop and start ECU.
    Power Steering ECU Assembly Sends an electrical power steering assist signal to the engine stop and start ECU.
    Crank Position Sensor Detects the crankshaft angle when the engine is stopped and sends this information to the ECM.
    ATF Temperature Sensor Detects the ATF temperature and if the temperature is within the stop and start operation temperature, the ECM sends a stop and start permission signal to the engine stop and start ECU.
    Engine Coolant Temperature Sensor Sends the coolant temperature to the engine stop and start ECU via the ECM.
    Generator Assembly Sends the generator assembly generation condition to the engine stop and start ECU via the ECM.
    Oil Pump with Solenoid Assembly Holds the ATF pressure during idle stop.

    *: Models with navigation system

  2. SYSTEM CONTROL


    1. Early Stage Injection Control


      1. Early stage injection control shortens the time it takes the engine to restart after the stop and start system stops the engine, thus allowing smooth initial acceleration.

      2. The ECM memorizes the crankshaft angle detected by the crank position sensor when the engine is stopped by the stop and start system.

      3. The ECM judges the injection required and decides which cylinder to ignite when the driver does restart operation. The ECM then uses this information as it starts the engine.

        B006JYVE03

    2. Hill-start Assist Function


      1. The driving force (creep phenomenon) of a former AT vehicle is regulated by depressing the brake pedal while stopped, and the driving force is transmitted by releasing the brake pedal when starting the vehicle. However, when starting a stop and start system equipped vehicle with its engine stopped due to the activation of the idle stop function, there is a short time delay before the driving force is generated as the engine will start after the brake pedal is released.

      2. The hill-start assist function is a system to assist starting of a stop and start system equipped vehicle on a slope to deal with the situation described above, retaining the brake hydraulic pressure until sufficient driving force is generated.

        Tech Tips


        • The hill-start assist function operates not only on a slope but also on a level surface.

        • Abnormal sounds may be heard, but this does not mean the brake is malfunctioning.

        • The brake pedal response may change or it may vibrate, but this does not mean it is malfunctioning.

    3. System Prohibit Control


      1. For safety, battery protection, comfort and ECU learning reasons, the engine stop and start ECU prohibits stop and start system operation if any one of the following conditions is met.

        Prohibition Reason Condition
        Safety If the engine is started with the hood open, such as when jump starting, engine restart operation cannot be ensured. Therefore, stop and start system operation will be prohibited. The operation of the system will be restored on the next trip.
        If the driver door or hood is opened before the engine stops, stop and start system operation will be prohibited for safety reasons.
        The brake booster vacuum is insufficient.
        The driver seat belt is unfastened before the engine stops.
        The engine catalyst is being quickly warmed up.
        Battery Protection The refresh charge continues for 0.5 to 1 hour, and is carried out approximately every 30 hours of driving. While refresh charge, stop and start system operation will be disabled.
        When the idling stop rate becomes higher than the predetermined rate, stop and start system operation will be disabled.
        When the battery voltage becomes low and the battery integrated current value drops to below the threshold value, stop and start operation will be disabled.
        Comfort If the air conditioning is on when the outside temperature is high and the evaporator temperature is high, stop and start system operation will be prohibited.
        If the air conditioning is on when the outside temperature is low, stop and start system operation will be prohibited.
        If the heater is on when the outside temperature is low and the engine coolant temperature is low, stop and start system operation will be prohibited.
        If the front DEF switch and blower switch are on, stop and start system operation will be prohibited.
        ECU Learning ECU learning is not complete.*
        Operation If the vehicle is stopped while the steering wheel is being operated, stop and start system operation will be prohibited.

        *: If the value learned by the ECU has been cleared by disconnecting the battery or for another reason, stop and start system operation will be prohibited until ECU learning is complete.

    4. Warning Control


      1. While the stop and start system stops the engine, one of following operations warns the driver: sounding the multi-buzzer in combination meter assembly, blinking the stop and start indicator light, displaying the multi-information display in combination meter assembly, or restarting the engine or stopping it from restarting.

        Operation Warning Control
        Hood is opened. The engine stops (mode changes to "stalled", and the engine cannot be restarted until the engine switch is turned off and then on (IG)).
        Driver seat door is opened with the shift lever in D position. The engine starts warning the buzzer sounds, and the stop and start indicator blinks.
        Driver seat belt is unfastened. The engine is starts.

    5. Operating Conditions at Engine Stop and Restart


      1. The engine may stop if all of these conditions are detected.

        Item Operating Condition
        Idle Stop Engine Coolant Temperature 40°C to 115°C (104°F to 239°F)
        AT Oil Temperature 25°C to 111°C (77°F to 231.8°F)
        Driver Door Closed
        Brake Booster Vacuum Sufficient brake booster vacuum
        Stop and Start System Cancel Switch (Combination Switch Assembly) Off condition
        Road Gradient -8° to 8°
        Vehicle Speed Vehicle speed changes from a constant speed to 0 km/h.
        Engine Speed 1250 r/min or less
        Shift Lever Position D
        Driver's Seat Belt 3 seconds or more elapse after the seat belt is fastened.
        Engine Hood Closed
        Battery Voltage 7.82 V or more at engine start.
        Battery Fluid Temperature -10°C to 70°C (14°F to 158°F)*1
        Battery Integrated Current*2

        When the integrated current value meets any of the following conditions:


        • -15444 A-sec or more: Status of Battery Charge Control is Charge Control Coordination Mode, Stop and Start Standalone Mode, Temperature High/Low Mode or Low Temperature Mode.*3

        • 0 A-sec or more: Status of Battery Charge Control is Stop and Start Restriction Mode.*4
        Air Conditioning During "cooling down or warming up" or defrost function is not operating.
        ECU Learning Completed
        Ambient Temperature -5°C (23°F) or more
        Steering Operation Not operated
        Accelerator Pedal The accelerator pedal is released.
        Brake Pedal*5

        • The brake pedal is depressed.

        • The brake master cylinder fluid pressure is 1.2 MPa (12.2 kg/cm2, 174 psi) or higher.

        *1: When the battery fluid temperature becomes -15°C (5°F) or lower or 75°C (167°F) or higher, control is prohibited. After control is prohibited and the battery fluid temperature rises to -10°C (14°F) or higher or falls to 70°C (158°F) or lower, control is performed.

        *2: Regarding Battery Integrated Current

        In the stop and start system, the engine stop and start ECU switches the system control mode (stop and start system control permitted/prohibited) based on the battery condition (charge/discharge condition) to protect the battery and to ensure stable engine restarting performance.

        The battery charge/discharge condition is determined from the integrated current value calculated from the battery state sensor assembly signal. The integrated current value is obtained by multiplying the current (ampere) detected by the battery state sensor assembly by the time (seconds), and is expressed in the unit A-sec. This can be measured by the Global TechStream (GTS).

        The engine stop and start ECU determines the power charge based on the integrated current value and prohibits stop and start system control if the value is below the threshold, because the battery might not be able to start the engine. The threshold varies according to the battery fluid temperature and battery charge condition.

        *3: After the integrated current value becomes -16434 A-sec or less, in order to charge the battery, control is prohibited until the value becomes -15444 A-sec or more.

        *4: After the integrated current value becomes -990 A-sec or less, in order to charge the battery, control is prohibited until the value becomes 0 A-sec or more.

        *5: When the engine is restarted, ensure proper braking force so that the vehicle does not advance.

      2. The engine will restart if any of these conditions are detected.

        Item Operating Condition
        Engine Restart Brake Booster Vacuum Insufficient brake booster vacuum.
        Air Conditioning When the air conditioning is on and a timer in the air conditioning amplifier assembly completes.
        When the automatic blower function is operating and a timer in the air conditioning amplifier assembly completes. Otherwise, a timer in the engine stop and start ECU completes.
        The A/C switch, blower switch or rear window defogger switch is turned on.
        Evaporator temperature exceeds threshold (threshold varies with temperature, humidity and amount of solar radiator).
        Stop and Start System Cancel Switch (Combination Switch Assembly) The stop and start system cancel switch (combination switch assembly) is turned on.
        Battery The battery voltage is less than 11.4 V.
        The battery integrated current drops to below the threshold value.
        Driver's Door The driver's door is opened.
        Driver's Seat Belt The driver's seat belt is unfastened.
        Vehicle Speed A vehicle speed signal is input.
        Accelerator Pedal The accelerator pedal is depressed.
        Brake Pedal* The brake pedal is released.
        Shift Lever Moved from D position to another position.
        Steering Operation The steering wheel is operated.

        *: If brake hold is operating, the engine does not restart even if the brake pedal is released.

    6. Idling Stop Control during Brake Hold Function Operation


      1. While the brake hold function is operating during the idle stop condition, the idle stop condition continues even if the brake pedal is released.

      2. By depressing the accelerator pedal, the engine restarts and the brake hold function is canceled.

        Tech Tips


        • Depending on the vehicle condition, idle stop may not be performed even during brake hold.

        • Depending on the vehicle condition, the engine may restart during brake hold. In this case, the vehicle will not start off since brake hold continues.

        • If any of the operation conditions are not met during engine stop by the stop and start system, the brake hold system will not operate. If the electrical parking brake is applied automatically, the engine will restart.

        B006JZUE03

  3. FUNCTION


    1. Settings of Stop and Start System


      1. By using the steering pad switch on the steering pad switch assembly and the multi-information display on the combination meter assembly or by pressing and holding the stop and start system cancel switch (combination switch assembly), the engine stop operation time due to stop and start control when the air conditioning system is on can be changed between Standard and Extended (the stop and start system has priority).

  4. DIAGNOSIS


    1. When the engine stop and start ECU detects a malfunction and CAN communication is normal, the engine stop and start ECU records information related to the malfunction. Furthermore, the stop and start indicator light in the combination meter assembly blinks to inform the driver that CAN communication is normal.

    2. The engine stop and start ECU also stores Diagnostic Trouble Codes (DTCs) related to malfunctions. DTCs can be read using the Global TechStream (GTS).