STOP AND START

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. Supplies battery voltage to the accumulator with solenoid assembly.
Transmission Floor Shift Assembly	Shift Lever Position Sensor	Detects the shift positions (Home, R, N, D or M), and transmits the shift position signal to the shift control ECU.
Shift Position Indicator	P Position Switch	Sends the parking lock application signals to the shift control ECU.
Shift Control ECU		Performs shift control for each shift position based on signals from the shift lever position sensor, P position switch and various ECUs and sends control signals to the ECM.
Vacuum Sensor Assembly*1		Detects the brake booster vacuum pressure and sends a signal to the engine stop and start ECU via the ECM.
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.
Ambient Temperature Sensor (Cooler Thermistor Assembly)		Sends the outside temperature signal to the air conditioning amplifier assembly.
Air Conditioning Amplifier Assembly		Sends the outside temperature signal and engine restart signal 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 cancel switch. If a system malfunction is detected, the stop and start cancel indicator light blinks to inform the driver.
	Multi-information Display	Displays the current idling stop time 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.
	Odo/trip Meter	Displays the current idling stop time. Displays the settings of the stop and start system or warning information, etc.
Integration Control and Panel Assembly	Stop and Start Cancel Switch	Operation of the system can be canceled by pressing the stop and start cancel switch. 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.
Skid Control ECU1/ Skid Control ECU Assembly2		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.
Steering Sensor		Detects the steering angle and sends signals to the engine stop and start ECU.
Yawrate Sensor		Detects the vehicle's longitudinal and lateral acceleration and sends signals to the engine stop and start ECU
External Backup Boost Converter (Eco Run Vehicle Converter Assembly)		Supplements the voltage drop when the engine is stopped to stabilize the audio output.
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.
Crankshaft Position Sensor		Detects the crankshaft angle when the engine is stopped and sends this information to the ECM.
Automatic Transmission Assembly	ATF Temperature Sensor	Detects the ATF temperature.
Automatic Transmission Assembly	Accumulator with Solenoid Assembly	Ensures sufficient oil pressure for automatic transmission operations when the engine is restarted after an idling stop.
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.

*1: Models with vacuum brake booster

*2: Models with electronically controlled brake system

SYSTEM CONTROL

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.
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.

System Prohibit Control

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.*3
	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.*1
ECU Learning	ECU learning is not complete.*2
Operation	If the vehicle is stopped while the steering wheel is being operated, stop and start system operation will be prohibited.

*1: Ensures proper brake force so that the vehicle does not advance forward when the engine is restart.

*2: 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.

*3: Models with vacuum brake booster

Warning Control

If any of the following operations are performed while the engine is stopped due to system control, the system will not restart the engine. The driver will be warned by a buzzer, or the engine will be regarded as stalled or will be restarted.

Operation	Warning Control
The engine 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))
The driver door is opened with the shift lever in D	The engine starts, warning buzzer sounds and stop and start indicator light blinks
The driver seat belt is unfastened	The engine starts

*: If the hood panel opens during an idling stop, the engine does not restart. In this case, the engine can be restarted using the engine switch (push start switch) after the shift lever is moved to P or N.

Operating Conditions at Engine Stop and Restart

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

Item		Operating Condition
Idle Stop	Engine Coolant Temperature	40°C to 100°C (104°F to 212°F)
	AT Oil Temperature	25°C to 110°C (77°F to 230°F)
	Driver Door	Closed
	Brake Booster Vacuum*5	Sufficient brake booster vacuum
	Stop and Start Cancel Switch	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, P
	Driver's Seat Belt	3 seconds or more elapse after the seat belt is fastened.
	Engine Hood	Closed
	Battery Voltage	7.94 V or more at engine start.
	Battery 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: -17971 A-sec or more: Status of Battery Charge Control is Charge Control Coordination Mode, Stop and Start Standalone Mode or Low Temperature Mode and Temperature High/Low Mode.3 0 A-sec or more: Status of Battery Charge Control is Stop and Start Restriction Mode.4
	Accelerator Pedal	The accelerator pedal is released.
	Air Conditioning	The cooling, heating and defrost functions are not operating.
	ECU Learning	Completed
	Ambient Temperature	-5°C (23°F) or more
	Steering Operation	Not operated The steering wheel is turned 180° or less.
	Drive Mode	Normal, Comfort or Eco mode is on.

*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 sensor signal. The integrated current value is obtained by multiplying the current (ampere) detected by the battery sensor 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 -19113 A-sec or less, in order to charge the battery, control is prohibited until the value becomes -17971 A-sec or more.

*4: After the integrated current value becomes -1152 A-sec or less, in order to charge the battery, control is prohibited until the value becomes 0 A-sec or more.

*5: Models with vacuum brake booster

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

Item		Operating Condition
Engine Restart	Brake Booster Vacuum*3	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, rear window defogger switch or mirror heater switch is turned on.
		Evaporator temperature exceeds threshold (threshold varies with temperature, humidity and amount of solar radiator)
	Stop and Start Cancel Switch	The stop and start cancel switch 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*1	The brake pedal is released.
	Shift Lever	The shift lever is moved from D to R, N or M/from P to D, R, N or M.
	Steering Operation	The steering wheel is operated.
	Cruise Control Operation*2	A vehicle ahead starting off has been detected during brake hold operation through the stop control function.
	Drive Mode	A mode other than Normal, Comfort and Eco is selected.

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

*2: Models with full-speed range following function

*3: Models with vacuum brake booster

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.
Idle stop control during dynamic radar cruise control (stop control) (Models with Full-speed Range Following Function)
1. If the vehicle stops through the stop control function while the dynamic radar cruise control is operating, idle stop is performed together with brake hold function operation.
2. If a vehicle ahead accelerating is detected, the engine automatically restarts.*
  
  Tech Tips
  
  *: Even if the engine restarts, brake hold continues. Therefore, the vehicle does not automatically start off.
  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 a certain time has elapsed after the vehicle was stopped in vehicle-to-vehicle distance control mode and the electric parking brake is applied automatically, the engine will restart.

FUNCTION
1. Settings of Stop and Start System
  1. Using the steering pad switch on the steering pad switch assembly and the multi-information display on the combination meter 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).
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).