MANUAL AIR CONDITIONER SYSTEM [MANUAL AIR CONDITIONER]

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Outline

•  The climate control unit performs the following controls based on the input signals from the each dial/switch and each sensor.

Control item

Control description
A/C compressor control
•  A/C compressor manual control
•  A/C cut-off control

Supplementary function
Fail-safe


Function


A/C compressor control

•  The A/C compressor control turns the A/C on/off based on the climate control unit operation and signals from each sensor.
A/C compressor manual control
•  The climate control unit switches the A/C compressor mode on or off according to the operation of the A/C switch.

A/C mode (A/C switch operation)

A/C indicator light
OFF → ON
On
ON → OFF
Off

A/C cut-off control
•  The PCM performs A/C cut-off control based on the input signal from the climate control unit and outputs an operation signal to the A/C relay (magnetic clutch). (See A/C CUT-OFF CONTROL [SKYACTIV-G 1.5, SKYACTIV-G 2.0].)


Fail-safe

•  If a malfunction is detected by the malfunction detection function, the fail-safe function performs the following controls to prevent malfunction operation of the air conditioner and malfunction of output devices.

Fail-safe function table

Part where malfunction is determined

Malfunction determined when ignition is switched ON

Ignition switched ON under malfunction condition
Ambient temperature sensor
Ambient temperature sensor input value is fixed at value right before malfunction.
Ambient temperature sensor input value fixed at 15 °C {59 °F}.
Evaporator temperature sensor
Evaporator temperature sensor input value fixed at 0 °C {32 °F}.
←
Engine coolant temperature sensor
Engine coolant temperature sensor input value fixed at 85 °C {185 °F}.
←
Air mix actuator (potentiometer)
Air mix actuator drive signal is stopped right after the malfunction is determined.
Control based on ambient temperature (Reference: Graph 1).
Airflow mode actuator (potentiometer)
Airflow mode actuator drive signal is stopped right when the malfunction is determined.
•  For manual operation, only vent or defroster mode is operable.
Control based on ambient temperature (Reference: Graph 2).
•  For manual operation, only vent or defroster mode is operable.
Air mix actuator (motor lock)
Air mix actuator drive signal is stopped right after the malfunction is determined.
Resumes output of the air mix actuator drive signal normally for 20 s after the ignition is switched ON (engine off or on). After that, motor output is stopped if a malfunction is detected.
Airflow mode actuator (motor lock)
Airflow mode actuator drive signal is stopped right when the malfunction is determined.
Resumes output of the mode actuator drive signal normally for 9 s after the ignition is switched ON (engine off or on). After that, motor output is stopped if a malfunction is detected.

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Block Diagram

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System Wiring Diagram

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Structural View

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Operation


A/C compressor control

1.  Based on the operation of each switch/dial and signals (1) from each sensor which change according to the vehicle conditions, the climate control unit performs A/C compressor mode determination (2) when the ignition is switched ON (engine off or on).

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2.  The climate control unit sends (3) the A/C signal to the PCM according to the result of the A/C compressor mode determination and corrections.

3.  The PCM turns the A/C relay on (4) based on the A/C signal and the signals from each sensor which change according to the vehicle conditions.

4.  When the A/C relay turns on, the magnetic clutch turns on (5).