STOP AND START SYSTEM

FUNCTION OF MAIN COMPONENTS

Component		Function
Engine Stop and Start ECU		Sends either an engine stop or restart signal to the ECM in according with 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.
Clutch Switch Assembly		Recognizes that the clutch pedal is not depressed and sends a signal to the engine stop and start ECU.
Clutch Start Switch Assembly		Recognizes that the clutch pedal is depressed and sends a signal to the engine stop and start ECU.
Neutral Position Switch		Recognizes that the shift lever is in N and sends a signal to the engine stop and start ECU.
Brake Vacuum Pressure Sensor		Detects the brake booster vacuum pressure and sends a signal to the engine stop and start ECU.
Engine Hood Courtesy Switch		Detects whether the hood is open or closed and sends a signal to the engine stop and start ECU.
Main Body ECU (Multiplex Network Body ECU)		Sends a front door courtesy light switch (driver) signal and front seat belt buckle switch (driver) signal to the engine stop and start ECU.
Front Door Courtesy Light Switch (Driver)		Detects whether the door is open or closed and sends a signal to the engine stop and start ECU via the main 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 via CAN communication.
Air Conditioning Amplifier Assembly		Sends an outside temperature signal, blower switch signal and A/C switch signal to the engine stop and start ECU.
Blower Switch		Sends a blower operation signal to the air conditioning amplifier assembly.
Heater Switch Assembly*		Sends a heater switch assembly on 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 system control.
	Stop and Start Cancel Indicator Light	Turns on to inform the driver that the system has been disabled when the following occurs: Stop and start system operation is prohibited by the stop and start system cancel switch assembly.
	Stop and Start Cancel Indicator Light	If a system malfunction is detected, the stop and start cancel indicator light blinks to inform the driver.
	Multi-information Display (ECO Time and ECO Odometer)	Displays the total amount of engine stoppage time occurring since the last reset.
Ecorun Cancel Switch Assembly		The operation of the system can be canceled by pressing the ecorun cancel 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.
Brake Actuator Assembly	Skid Control ECU	Sends a vehicle speed signal to the engine stop and start ECU.
Center Airbag Sensor Assembly		Sends airbag deployment information in the event of a collision and deceleration signal to the engine stop and start ECU.
Generator Control ECU Assembly	Baterry Temperature Sensor	Sends a baterry temperature sensor signal to the engine stop and start ECU.

*: Models with combustion type power heater

OPERATING CONDITION

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	A predetermined temperature*1 to 105°C (221°F)
	Outside Temperature	-5°C (-23°F) or more
	Driver Door	Closed
	Brake Booster Vacuum	Sufficient brake booster vacuum
	Ecorun Cancel Switch Assembly	Off condition
	Vehicle Speed	0 km/h (0 mph)
	Clutch Pedal	Released
	Shift Lever Position	Neutral
	Engine Hood	Closed
	Battery Voltage	6.5 V or more at engine start
	Battery Temperature	-10°C to 70°C (14°F to 158°F)
	Battery Integrated Current*2	0 A-sec or more: After engine start by ignition switch operation After the integrated current value has increased to 0 A-sec or more at least once since ignition switch was turned to ON: More than -5544 A-sec: When a low battery temperature condition is not detected (the battery temperature is 11°C (51.8°F) or more). More than -990 A-sec: When a low battery temperature condition is not detected (the battery temperature is less than 10°C (50°F)).
	Air Conditioning	Off or on with an outside temperature of 25°C (77°F) or lower and an evaporator temperature of 9°C (48°F) or lower.
	Heater	Off or on with an outside temperature of 10°C (50°F) or higher and an engine coolant temperature of 45°C (113°F)or higher.

Tech Tips

*1: The lowest operating temperature is determined by environmental conditions.

*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 form the battery current sensor signal. The integrated current value is obtained by multiplying the current (ampere) detected from the battery current sensor by the time (seconds), and it is expressed in the unit A-sec. This can be measured by using the Global TechStream (GTS). The engine stop and start ECU determines the power charge based on the integrated current value, and it 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 temperature and battery charge condition.

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	The timer in the air conditioning amplifier assembly operates when the air conditioning is on.
	Air Conditioning/Heater	The A/C switch or blower switch is turned on.
	Ecorun Cancel Switch Assembly	The ecorun cancel switch assembly is turned on.
	Heater Switch Assembly*1	The heater switch assembly is turned on.
	Battery	Less than 11.4 V
	Driver Door	The driver door is opened.
	Driver Seat Belt	Unfastened.
	Vehicle Speed	Vehicle speed signal is input.
	Clutch Pedal	Depressed.*2
	DPF Warning Indicator Light	Illuminates.

Tech Tips

*1: Models with combustion type power heater

*2: When the shift lever position is N.

SYSTEM CONTNROL

System Prohibit Control

For safety, battery protection, comfort and ECM 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 for 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.
	If the air conditioning is on when the outside temperature is low, stop and start system operation will be prohibited.
	If the engine stop and start ECU receives an airbag deployment signal in the event of a collision, stop and start system operation will be prohibited for safety reasons.
Battery Protection	If the electrical load is high and the engine is stopped for a long period of time, stop and start system operation will be prohibited.
	A refresh charge is performed every time the vehicle is driven for a total of 20 hours. During the refresh charge, which takes 30 minutes to 1 hour, stop and start system operation will be prohibited.
	If the ratio of the engine stop duration to the time the ignition switch is being turned to ON exceeds a certain value, the stop and start system will be prevented from operating.
	If the battery integrated current is less than 0 A-sec after engine start by ignition switch operation, the stop and start system operation will be prohibited. After the integrated current value increases to 0 A-sec or more once: -3110 A-sec or less: When the battery temperature is 10°C (50°F) or more, stop and start system operation will be prohibited. -864 A-sec or less: When the battery temperature is less than 10°C (50°F), stop and start system operation will be prohibited.
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 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 (models with automatic air conditioning).
ECM Learning	ECM learning is not complete.

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 the buzzer sounds or the stalling of engine:

Operation	Warning Control
Hood is opened.	The engine changes to 'stalled' or restarted.
Shift lever is moved without depressing the clutch pedal.	Buzzer sounds.

DIAGNOSIS

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 fault. Furthermore, the stop and start indicator light in the combination meter assembly blinks to inform the driver that all CAN communication is normal.
The engine stop and start ECU will also store the Diagnostic Trouble Code (DTC) of the malfunctions. The DTC can be read using the Global TechStream (GTS).