AIR CONDITIONER i-stop CONTROL [FULL-AUTO AIR CONDITIONER]

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Purpose

•  The heater control unit controls i-stop to permit/inhibit its operation (engine stop control) according to the air conditioner system operation conditions.

Function

•  The climate control unit determines i-stop (engine stop control) control according to the operation condition of the air conditioner system and sends i-stop (engine stop control) request signals to the PCM.
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•  If i-stop operates (engine stop control), the climate control unit operates the air mix actuator and controls the airflow temperature to decrease the engine coolant temperature or correct the temperature increase of the air passing through the evaporator.
Caution
•  Occupants may hear the sound of the air mix actuator operating because there is no engine sound during the i-stop operation (engine stop control). The operation sound of the air mix actuator may be heard because the airflow temperature control is performed even during the i-stop operation (engine stop control), however, this does not indicate a system malfunction.

Operation


i-stop request control (i-stop (engine stop control) permit/ i-stop (engine stop control) inhibit)

•  The climate control unit sends i-stop (engine stop control) permit or i-stop (engine stop control) inhibit request signals to the PCM according to the operation condition of the air conditioner system.
i-stop (engine stop control) inhibit request
•  The climate control unit sends an i-stop (engine stop control) inhibit request signal to the PCM when it detects any of the following conditions:

i-stop (engine stop control) inhibit conditions

No.

Item

Vehicle condition
1
Climate control unit malfunction determined
A DTC is detected in relation to the following parts:
•  Solar radiation sensor
•  Ambient temperature sensor
•  Cabin temperature sensor
•  Evaporator temperature sensor
•  Heater core temperature sensor
•  Engine coolant temperature sensor
•  Airflow mode actuator
•  Air mix actuator
2
CAN line error determined
Signal reception error occurs on climate control unit side in relation to the following signals:
•  Ambient temperature signal
•  Engine coolant temperature signal
•  Engine operation status signal (i-stop status signal)
3
Ambient temperature
Ambient temperature is -10 °C {14 °F} or below, or 50 °C {122 °F} or more
4
Airflow mode control status
During manual defroster control
5
Set temperature, compressor control mode
MAX HOT or MAX COLD (A/C or ECO mode)
6
Auto air conditioner target temperature attainment status
If any of the following signals do not meet the i-stop (engine stop control) permit conditions (Comfortable cabin temperature control not performed):
•  Cabin temperature (cabin target temperature and cabin temperature relation)
•  Evaporator temperature
•  Heater core temperature

i-stop (engine stop control) permit request
•  The climate control unit sends an i-stop (engine stop control) permit request signal to the PCM when it detects any of the following conditions:

i-stop (engine stop control) permit conditions

No.

Item

Vehicle condition
1
Blower motor control status
•  Blower motor is off
•  However, i-stop (engine stop control) inhibit conditions No.1 to 3 must not be in effect.
2
Set temperature, compressor control mode
•  MAX COLD
•  Compressor control: Off
•  Blower motor is ON
•  However, i-stop (engine stop control) inhibit conditions No.1 to 4 must not be in effect.
3
Auto air conditioner target temperature attainment status
•  Blower motor is ON
•  Compressor control: ON
•  The relation between the cabin target temperature and cabin temperature meets the i-stop (engine stop control) permit conditions (comfortable cabin temperature control is performed)
•  However, i-stop (engine stop control) inhibit conditions No.1 to 6 must not be in effect.


A/C control start during i-stop (engine stop control)

•  When the A/C operation is stopped by the i-stop control, and while i-stop (engine stop control) permit condition No. 3 is met, the climate control unit starts A/C control corresponding to the engine-stop condition if it detects an engine-stop condition based on the i-stop condition signal sent from the PCM.
•  If the engine is stopped during A/C control, the A/C compressor magnetic clutch turns off and the A/C indicator light remains in an illuminated condition. When the engine is restarted, the A/C compressor magnetic clutch turns on again.


Recovery to normal A/C control

•  When recovery condition a or b is met while the engine is stopped by the i-stop control, the climate control unit sends an engine restart request signal to the PCM.
•  It returns to the normal A/C control when the engine is restarted.
Recovery condition a:
•  i-stop cancel determination condition is met

i-stop (engine stop control) cancel determination conditions

Compressor control mode

Airflow mode

VENT

BI-LEVEL

HEAT, DEF/HEAT, DEFROSTER
A/C, ECO, OFF
If the following conditions are met:
•  Evaporator temperature is at i-stop control specification or more
If any one of the following conditions are met:
•  Evaporator temperature is at i-stop control specification or more
•  Heater core temperature is at i-stop control specification or less
If the following conditions are met:
•  Heater core temperature is at i-stop control specification or less

Recovery condition b:
•  Any one of the following i-stop (engine stop control) inhibit conditions is met
―  No.1 climate control unit malfunction determination
―  No.2 CAN transmission error determination
―  No.4 mode control status
―  No.5 set temperature, compressor control mode