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ATC-28
AIR CONDITIONER CONTROL
Description of Control SystemBJS000FL
The control system consists of input sensors, switches, the unified meter and A/C amp. (microcomputer) and
outputs. The relationship of these components is shown in the figure below:
SJIA1649E
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ATC-44
TROUBLE DIAGNOSIS
Auto Amp. Terminals and Reference ValueBJS000FW
Measure voltage between each terminal and ground by referring ter-
minals and reference value for unified meter and A/C amp.
PIN CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUE FOR UNIFIED METER AND A/C AMP.
RJIA2732E
RJIA2734E
Te r m i n a l
No.Wire
colorItemIgnition
switchConditionVoltag e
(V)
1 L CAN-H — — —
11 P C A N - L — — —
21 Y/R Power supply from BATT OFF — Battery voltage
22 G Power supply from IGN ON — Battery voltage
29 B Ground (Power) ON — Approx. 0
30 B Ground ON — Approx. 0
35 V Power supply from ACC ACC — Battery voltage
39 O/B Ambient sensor — — —
40 LG In-vehicle sensor — — —
41 R/W Intake sensor — — —
42 SB Compressor ON signal ONA/C switch: ON (Blower motor
operates.)Approx. 0
OFF switch: ON (A/C System:
OFF)
43 L/R A/C LAN signal ON —
SJIA1423J
SJIA1453J
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TROUBLE DIAGNOSIS
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46 W/L Power supply from IGN 2 ON — Battery voltage
47 L/RBlower fan motor feedback
signalON Fan speed: 1st speed Approx. 8
49 B/Y Sensor ground ON — Approx. 0
50 O Sunload sensor — — —
54 L/WPower supply for each door
motorON — Battery voltage
57 BR/W FAN ON signal ONAUTO switch: ON (Blower
motor operates.)Approx. 0
AUTO switch: OFF Approx. 5
60 L/YBlower fan motor control sig-
nalONFan speed: 1st - 4th speed Approx. 2.5 - 3.5
Fan speed: 5th speed Approx. 9.5 - 10.5 Terminal
No.Wire
colorItemIgnition
switchConditionVoltage
(V)
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ATC-46
TROUBLE DIAGNOSIS
Self-diagnosis FunctionBJS000FX
DESCRIPTION
The self-diagnosis system diagnoses sensors, door motors, blower motor, etc. by system line. Refer to appli-
cable sections (items) for details. Shifting from usual control to the self-diagnosis system is accomplished by
starting the engine (turning the ignition switch ON) and pressing A/C switch for at least 5 seconds. The A/C
switch must be pressed within 10 seconds after starting the engine (ignition switch is turned ON). This system
will be canceled by either pressing AUTO switch or turning the ignition switch OFF. Shifting to the next step is
accomplished by means of pressing temperature control switch (driver side), as required.
Additionally sifting from STEP-5 to AUXILIARY MECHANISM is accomplished by means of pressing (fan)
control switch (UP).
SJIA1670E
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TROUBLE DIAGNOSIS
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FUNCTION CONFIRMATION PROCEDURE
1. SET IN SELF-DIAGNOSIS MODE
1. Turn ignition switch ON.
2. Set in self-diagnosis mode as follows. Within 10 seconds after starting engine (ignition switch is turned
ON.), press A/C switch for at least 5 seconds.
CAUTION:
Press A/C switch after indicating LED of intake switch.
If battery voltage drops below 12 V during diagnosis STEP-3, door motor speed becomes slower
and as a result, the system may generate an error even when operation is normal. To avoid this,
start engine before performing this diagnosis.
Former STEP-1 (LEDs and display screen are checked) does not exist in this self-diagnosis func-
tion.
>> GO TO 2.
2. STEP-2: SENSOR CIRCUITS ARE CHECKED FOR OPEN OR SHORT CIRCUIT
Does code No. 20 appear on the display?
YES >> GO TO 3.
NO >> GO TO 13.
3. CHECK TO ADVANCE SELF-DIAGNOSIS STEP-3
Press temperature control switch (UP, driver side).
Advance to self
-diagnosis STEP-3?
YES >> GO TO 4.
NO >> Replace A/C and AV switch. (Temperature control switch is malfunctioning.)
4. CHECK TO RETURN SELF-DIAGNOSIS STEP-2
Press temperature control switch (DOWN, driver side).
Return to self
-diagnosis STEP-2?
YES >> GO TO 5.
NO >> Malfunctioning A/C and AV switch or unified meter and A/C amp. Refer to AT C - 9 4 , "
Self-diagno-
sis" .
5. STEP-3: MODE DOOR AND INTAKE DOOR POSITIONS ARE CHECKED
Press temperature control switch (UP, driver side).
Does code No. 30 appear on the display?
YES >> GO TO 6.
NO >> GO TO 14.
RHA970DB
RHA869DD
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TROUBLE DIAGNOSIS
ATC-49
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8. STEP-5: TEMPERATURE OF EACH SENSOR IS CHECKED
1. Press temperature control switch (UP, driver side).
2. Code No. 51 appears on the display.
>> GO TO 9.
9. CHECK AMBIENT SENSOR
Press (DEF) switch one time. Temperature detected by ambient
sensor is indicated on the display.
NOTE:
If the temperature indicated on the display greatly differs from the
actual temperature, check sensor circuit first, and then check sensor.
OK or NG
OK >> GO TO 10.
NG >> Go to Ambient Sensor Circuit. Refer to AT C - 9 6 , "
Ambi-
ent Sensor Circuit" .
10. CHECK IN-VEHICLE SENSOR
Press (DEF) switch for the second time. Temperature detected
by in-vehicle sensor is indicated on the display.
NOTE:
If the temperature indicated on the display greatly differs from the
actual temperature, check sensor circuit first, and then check sensor.
OK or NG
OK >> GO TO 11.
NG >> Go to In-vehicle Sensor Circuit. Refer to AT C - 9 9 , "
In-
vehicle Sensor Circuit" .
11 . CHECK INTAKE SENSOR
Press (DEF) switch for the third time. Temperature detected by
intake sensor is indicated on the display.
NOTE:
If the temperature indicated on the display greatly differs from the
actual temperature, check sensor circuit first, and then check sensor.
OK or NG
OK >> GO TO 12.
NG >> Go to Intake Sensor Circuit. Refer to ATC-105, "
Intake
Sensor Circuit" .
RJIA3240E
RJIA3241E
RJIA3242E
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ATC-50
TROUBLE DIAGNOSIS
12. CHECK CAN COMMUNICATION ERROR
1. Press intake switch.
2. CAN communication error between the unified meter and A/C
amp. and the display unit or display control unit can be detected
as self-diagnosis results. (If plural errors occur, the display of
each error will blink twice for 0-5 second intervals.) .
OK or NG
OK >> 1. Turn ignition switch OFF or AUTO switch ON.
2. INSPECTION END
NG >> Go to CAN communication. Refer to LAN-49, "
CAN Sys-
tem Specification Chart" .
Unified meter and A/C amp. - Display unit or Display
control unit.
13. CHECK MALFUNCTIONING SENSOR
Refer to the following chart for malfunctioning code No.
(If two or more sensors malfunction, corresponding code Nos. blink respectively twice.)
*1: Perform self-diagnosis STEP-2 under sunshine.
When performing indoors, aim a light (more than 60 W) at sunload sensor, otherwise code No. 25 will indicate
despite that sunload sensor is functioning properly.
*2: AT C - 9 6 , "
DIAGNOSIS PROCEDURE FOR AMBIENT SENSOR" .
*3: ATC-100, "
DIAGNOSIS PROCEDURE FOR IN-VEHICLE SENSOR" .
*4: ATC-105, "
DIAGNOSIS PROCEDURE FOR INTAKE SENSOR" .
*5: ATC-102, "
DIAGNOSIS PROCEDURE FOR SUNLOAD SENSOR" .
*6: AT C - 6 8 , "
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR PBR" .
>> INSPECTION END
RJIA1762E
Code No. Malfunctioning sensor (Including circuits) Reference page
21 / −21 Ambient sensor *2
22 / −22 In-vehicle sensor *3
24 / −24 Intake sensor *4
25 / −25
Sunload sensor
*1*5
26 / −26 Air mix door motor PBR (Driver side)
*6
27 / −27 Air mix door motor PBR (Passenger side)
PJIA0022E
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TROUBLE DIAGNOSIS
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COMPONENT DESCRIPTION
Unified Meter and A/C amp. (Automatic Amplifier)
The unified meter and A/C amp. has a built-in microcomputer which
processes information sent from various sensors needed for air con-
ditioner operation. The air mix door motor, mode door motor, intake
door motor, blower motor and compressor are then controlled.
When the various switches and temperature contorol switch are
operated, data is input to the unified meter and A/C amp. from the
display unit / display control unit using CAN communication.
Self-diagnosis functions are also built into unified meter and A/C
amp. to provide quick check of malfunctions in the auto air condi-
tioner system.
Potentio Temperature Control (PTC)
The PTC is built into the A/C and AV switch. It can be set at an inter-
val of 0.5°C in the 18°C to 32°C temperature range by turning tem-
perature control switch. The set temperature is displayed.
DIAGNOSIS PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
RJIA2732E
RJIA3253E
SJIA0301E