A/C-ECU

CONTROL

FORCIBLE DEFROSTER CONTROL <WITH SEMIAUTOMATIC A/C>

When the defroster position are selected, the A/C is automatically turned ON. At this time, the outside/inside air selection damper is operated to the fresh-air position to defrost the windshield glass quickly.

CAN COMMUNICATION <WITH SEMIAUTOMATIC A/C>

The A/C-ECU and engine-A/T-ECU communicate with each other through CAN communication. The idle-up speed of the engine is controlled according to the A/C load to secure the cooling performance in summer driving and improve fuel consumption in seasons with moderate temperature.

note

For further details on CAN, refer to

GROUP 54C, CAN.

REAR WINDOW DEFOGGER TIMER CONTROL

In order to prevent battery consumption, the defogger is automatically turned OFF, 20 minutes after it is turned ON.

DETECTION CONTROL FOR REFRIGERANT LEAKS

The refrigerant level is estimated by the refrigerant pressure and ambient temperature. When the refrigerant level is judged to be below 20%, the A/C indicator flashes and A/C compressor clutch is disengaged in order to reduce the damage to the A/C compressor.

AS&G CONTROL WHEN A/C SYSTEM IS OPERATING <VEHICLES WITH AS&G>

The AS&G operation changes depending on the A/C system operation status.

WHEN IDLE STOP IS NOT PERFORMED DUE TO A/C SYSTEM OPERATION

In the following conditions, the idle stop is not performed by the request from the A/C.

Outside air temperature is extremely low (3°C or less).
The mode selection dial is in the defroster position.
The cooling performance is not achieved sufficiently (only when the A/C switch is ON).
Engine coolant temperature is low (60°C or less).

WHEN IDLE STOP IS PERFORMED REGARDLESS OF A/C OPERATION

In the following conditions, the idle stop is not prohibited by the request from the A/C.

The blower dial is ON, A/C switch is OFF, and the mode selection dial is in the positions other then the defroster.
The blower dial is in the off position (the A/C system is not operating).

A/C SYSTEM OPERATION STATUS DURING IDLE STOP

The A/C system operation status during idle stop is as follows.

During idle stop, only air blowing can be performed because the A/C compressor stops together with the engine.
When the A/C switch is turned ON during idle stop and air blowing, the idle stop may be prohibited depending on the temperature conditions.
When the mode selection dial is moved to the ±1 notch range of the defroster during idle stop and air blowing, the idle stop is forcibly prohibited in order to secure safe visibility.

ADVICE

High air volume makes the idle stop difficult.
To blow the air from the defroster and make the idle stop, the use of DEF/FACE or DEF/FOOT is recommended.
When the temperature adjustment is turned to setting of 22 or higher, the idle stop time becomes longer.
In summer, due to the high outside air temperature, the idle stop time is longer with the inner air mode than the outer air mode.

CAN COMMUNICATION INPUT SIGNALS TABLE

Signal	Transmitter ECU
Engine speed signal	Engine-A/T-ECU
Engine coolant temperature signal
A/C information signal
Ambient temperature signal	Combination meter
Vehicle speed signal	Combination meter
Blower fan ON signal	ETACS-ECU

DIAGNOSTIC FUNCTION

Code No.	Diagnostic item	Substitutive value in case of diagnosis code output
B1001	Interior temperature sensor system (short circuit)	-
B1002	Interior temperature senor system (open circuit)	-
B1021	Air thermo sensor system (short circuit)	-5°C
B1022	Air thermo sensor system (open circuit)	-5°C
B1084	Rear window defogger system (open circuit or short to earth)	-
B1085	Rear window defogger system (open circuit)	-
B1086	Outside/inside air selection damper control motor system (open circuit or short to earth)	-
B1087	Outside/inside air selection damper control motor system (open circuit or short to earth)	-
B1088	Air mixing damper control motor and potentiometer sensor system (short circuit)	-
B1089	Air mixing damper control motor and potentiometer sensor system (open circuit)	-
B1090	Air mixing damper control motor and potentiometer activating system (anticlockwise)	-
B1091	Air mixing damper control motor and potentiometer activating system (clockwise)	-
B1092	ETACS signal reception failure	-
U1073	Bus off error	-
U1100	Engine-related CAN timeout	-
U1108	Combination meter CAN communication time-out	-
U1109	ETACS-ECU CAN communication time-out	-

SERVICE DATA OUTPUT

Item No.	Check item
11	A/C Pressure sensor
12	A/C switch
13	Blower fan
14	Mode select SW (DEF) position
15	Illumination
16	Acceleration cut request
17	Engine speed
18	Out/in select damp poten (target)
19	Ambient temperature sensor
20	Air thermo sensor
21	Interior temperature sensor
22	Air mixing damper potentiometer
23	Temperature setting
24	Engine coolant temp. sensor
25	Battery voltage
26	Vehicle speed
27	A/C Compressor drive request
28	A/C switch
29	Refrigerant leak
30	PTC heater request
31	Out/in select damp potentiometer
32	Air mixing potentiometer (target)
33	Cooling fan motor level request
34	Idle up request

ACTUATOR TEST

Item No.	Check item
35	Rear defogger switch: OFF
36	Rear defogger switch: ON
37	In/out select damper: FRESH
38	In/out select damper: REC
39	A/C compressor drive: 0%
40	A/C compressor drive: 100%
41	A/C compressor drive: 50%
42	Air mix damper motor: 0%
43	Air mix damper motor: 100%
44	Air mix damper motor: 50%