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5) Warm up engine to the normal operating temperature and keep it at the specified idle speed.
6) Turn A/C switch ON, set blower speed selector at maximum speed position, temperature selector at
maximum cold position, airflow selector at face
position, and air intake switch at recirculation
position. (Confirm that A/C compressor and
condenser fans are working.)
7) Wait for ten minutes to stabilize the A/C operation.
8) Open front windows, front doors and engine hood.
9) With about 20 mm (0.8 in.) of dry bulb thermometer
(1) put right in front of center ventilation louver and a
wet and dry bulb thermometer (2) near air inlet of
HVAC unit. 10) Check for each pressure of low side and high side if
it is within shaded range of graph. If each gauge
reading is out of specified pressure, correct defective
part referring to the following table.
NOTE
Pressure registered on gauge varies with
ambient temperature. Therefore, use the
graphs when determining if pressures are
normal or not.
Low side and high side pressure example,
Gauges should read as follows when ambient
temperature is 30 °C (86 °F)
Pressure on high pressure gauge (HI): 1590 –
1940 kPa (15.9 – 19.4 kg/cm2)
Pressure on low pressure gauge (LO): 270 – 430
kPa (2.7 – 4.3 kg/cm
2)
2
1
I4RS0B720004-01
[A]: Pressure of high pressure gauge
[B]: Pressure of low pressure gauge
[C]: Ambient temperature
[D]: Humidity [E]: Acceptable range
22
312.9 2200
0 1
2 3 30 70 30 70 %
4 5 6 7 8 9
10
11 12 13 14 15
16 17
18
19 21
298.7 2100
20
14.2 28.4 42.7 56.9 71.1 85.3 99.5
113.8 128.0 142.2
151.4
170.6
184.9 199.1
213.3 227.5
241.7
256.0
270.2
284.4
100 200 300 400 500 600 700 800 900
1000 1100 1200
1300
1400 1500 1600
1700 1800
1900
2000
25 30 35
77 86 95
psi kPa kg/cm
2
C
F
“A”
“B”
“C”
“D”
23
2300
327.1
[A]
[B]
[C][D][E]
[E]
I7RS0A721006-01
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11) Check inlet port temperature-to-outlet port temperature relationship using the graph. For example, if temperature
near air inlet of HVAC unit is 30 °C (86 °F) and the one at air outlet of center ventilation louver is 17 °C (62.6 °F),
their crossing point is within acceptable range as shown in the graph. In this case, cooling performance is
satisfactory and proper.
12) If crossing point is out of acceptable range, diagnose trouble referring to the following table.
Thermometer at center duct
NOTE
If ambient temperature is approximately 30 °C (86 °F), it is possible to diagnose A/C system in detail
referring to the following table.
[A]: Temp at air outlet of center ventilation louver [C]: Humidity
[B]: Temp near air inlet of HVAC unit [D]: Acceptable range
ConditionPossible cause Correction
Crossing point is higher
than acceptable range
(“E” area) Insufficient or excessive charge of refrigerant Check refrigerant pressure.
Dirty or bent A/C evaporator fins
Clean or repair.
Air leakage from cooling (heater) unit or air duct Repair or replace.
Malfunctioning, switch over function of door in
cooling (heater) unit Repair or replace.
Compressor malfunct ion Check compressor.
Crossing point is lower
than acceptable range
(“F” area) Insufficient air volume from center duct
(Heater blower malfunction)
Check blower motor and fan.
Compressor malfunct ion Check compressor.
8 9
10 11 12 13 14
15 16 17 18 19
20
21
22
23
24
25 26
27
28
46.4 48.2 50.0 51.8 53.6 55.4 57.2 59.0 60.8 62.6 64.4
66.2 68.0
69.8
71.6
73.4
75.2
77.0
78.8 80.6
82.4
25 30 35
77 86 95
F C
C
F
“E”
“F”30 70 %
[A]
[B][C]
[D]
I7RS0A721007-01
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Auto A/C Electronic Control Input / Output Table
HVAC Control Module Operation DescriptionS7RS0B7221002
Temperature Control
HVAC control module calculates the target temperature
control door position based on signals from the
temperature selector, inside air temperature sensor,
outside air temperature sensor and sunload sensor and
controls the temperature control actuator so that the
current position of the temperature control door matches
its target position.
Fan Speed Control
HVAC control module calculates the target blower fan
speed based on signals from the temperature selector,
inside air temperature sensor, outside air temperature
sensor and sunload sensor, compares it with the current
blower fan speed inputted from the blower motor
controller to control the current blower fan speed to the
target level.
Air Flow Outlet Control
HVAC control module calculates the target temperature
control door position based on signals from the
temperature selector, inside air temperature sensor,
outside air temperature sensor and sunload sensor.
Using thus obtained target temperature control door
position, it further calculates the target air flow control
door position and controls the ai r flow control actuator so
that the current air flow c ontrol door position becomes
the target position. Air Intake Position Control
HVAC control module determines the position of the air
intake control door based on signals from the
temperature selector, inside air temperature sensor,
outside air temperature sensor and sunload sensor and
selects any of the following positions by controlling the
position of the air intake control door.
• FRESH position (FRE)
• RECIRCULATION position (REC)
• MIX position (MIX)
Refrigerant Type IdentificationS7RS0B7221003
Refer to “Refrigerant Type Identification”.
Sub-Cool A/C System DescriptionS7RS0B7221005
Refer to “Sub-Cool A/C System Description”.
A/C Operation DescriptionS7RS0B7221006
Refer to “A/C Operation Description”.
Sunload sensor
Outside air temperature sensor Evaporator temperature sensor
A/C refrigerant pressure sensor
Temperature selector
MODE (air flow) selector
Blower speed selector
Air intake selector
AUTO switch
A/C switch
Compressor
Blower motor controller
Temperature control actuator
Air flow control actuator
Air intake control actuator
BCM
ECM
Data link connector
HVAC control module
CPU
ECT sensor
Inside air temperature sensor
VSS
*
I5RS0C722002-02
*: CAN communication
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Diagnostic Information and Procedures
A/C System Symptom DiagnosisS7RS0B7224001
4. Rear defogger relay 15. Evaporator temperature sensor 26. Radiator cooling fan relay No.1 37. Rear defogger switch
5. Rear defogger 16. Sunload sensor 27. Radiator cooling fan relay No.2 38. To BCM
6. Blower motor relay 17. Junction block assembly 28. Radiator cooling fan relay No.3 39. To ECM
7. Blower motor 18. ECM 29. Information display 40. To main relay
8. Blower motor controller 19. ECT sensor 30. Lighting switch 41. To main fuse
9. DLC 20. Radiator cooling fan motor 31. A/C switch 42. Back-light
10. Air intake actuator 21. Compressor relay 32. MODE (air flow) selector 43. Defroster indicator 11. Air flow control actuator 22. Compressor 33. Air intake selector 44. Rear defogger indicator
Condition Possible cause Correction / Reference Item
No cool air comes out (A/
C system does not
operate) No refrigerant
Perform recovery, evacuation and charge
referring to “Operation Procedure for
Refrigerant Charge”.
Fuse blown Check related fuses, and then check for short
circuit to ground.
A/C switch faulty Check A/C switch referring to “Inspection of
HVAC Control Module and Its Circuit”.
Evaporator temperature sensor faulty Check evaporator temperature sensor
referring to “Evaporator Thermistor
(Evaporator Temperature Sensor) Inspection”.
A/C refrigerant pressure sensor faulty Check A/C refrigerant pressure sensor
referring to “A/C Refrigerant Pressure Sensor
and Its Circuit Inspection”.
Wiring or grounding faulty Repair as necessary.
ECT sensor faulty Check ECT sensor referring to “ECT Sensor
Inspection in Section 1C”.
ECM faulty Check ECM referring to “A/C System
Inspection at ECM”.
HVAC control module faulty Check HVAC control module referring to
“Inspection of HVAC Control Module and Its
Circuit”.
Magnet clutch faulty Check magnet clutch. Referring to “Magnet
Clutch Inspection”.
Compressor drive belt loosened or
broken Adjust or replace drive belt.
Compressor faulty Check compressor.
Compressor relay faulty Check compressor relay referring to
“Compressor Relay Inspection”.
Temperature selector, blower speed
selector, and/or air flow selector faulty Check HVAC control module referring to
“Inspection of HVAC Control Module and Its
Circuit”.
BCM faulty Check BCM referring to “Inspection of BCM
and its Circuits in Section 10B”.
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Scan Tool DataS7RS0B7224007
As the data values given in the following are standard values estimated on the basis of values obtained from the
normally operation vehicles by using a scan tool, use them as reference values. Even when the vehicles are in good
condition, there may be cases where the checked values do not fall within each specifies data range. Therefore,
judgement as abnormal should not be ma de by checking with these data alone.
Scan Tool Data Condition Normal Condition / Reference
Va l u e
) TEMP CONT
SWITCH Each reference value is relative to the position of
temperature selector of HVAC control module. Max Cool, 18.5
°C (65 ° F), 19 °C (66
° C) – 31 °C (88 °F), 31.5 °C (89 °F),
Max Hot
) CABIN
TEMPERATURE Reference value is relative to in-car temperature. –6.5
°C – 57.25 ° C
(20.3 °F – 135.05 °F)
) OUTSIDE AIR TEMP Reference value is relative to outside air
temperature. –23.3
°C – 65.95 °C
(–9.94 °F – 150.71 °F)
) EVAPORATOR
TEMP Reference value is relative to temperature of
evaporator. –29.7
°C – 59.55 °C
(–21.46 °F – 139.19 °F)
) COOLANT TEMP At specified id le speed after warming up. 80 °C – 100 °C (176 ° F – 212 ° F)
) SUN LOAD Reference value depends on the situation. 0 W/m
2 – 4447.8 W/m2
)MODE CONT
SWITCH Each reference value is relative to the position of air
flow selector of HVAC control module.
AUTO, FACE, B/L, FOOT, D/F, DER
) FAN CONT SWITCH Each reference value is relative to the position of
blower speed selector of HVAC control module. AUTO, OFF, 1st, 2nd – 7th, 8th
) FAN DESIRED VOLT Reference value is relative to the position of blower
speed selector of HVAC control module. 0 – 16.0 V
) AIR MIX POS SEN Reference value is relative to the position of
temperature selector of HVAC control module. about 2.0 V (Max Hot)
about 4.0 V (Max Cool)
) MODE POS SENSOR Reference value is relative to the position of air flow
selector of HVAC control module. about 1.6 V (DEF)
about 4.0 V (VENT)
) A/C CONT SIG A/C system is ON. ON
A/C system is OFF. OFF
) BLOWER LOAD SIG Position of blower speed selector is 1st position or
more.
ON
Position of blower speed selector is OFF position. OFF
) AIR INTAKE MODE Fresh air (FRE) mode is activated. FRE
Recirculation air (REC) mode is activated. REC
AUTO mode is activated. AUTO
) REFRIGERANT
PRESSURE Engine running. A/C ON (A/C is operating)
at ambient temperature:
30
°C (86 °F) 1470 – 1770 kPa For more details,
refer to pressure of high pressure
gauge under “A/C System Performance Inspection”
A/C OFF (A/C is not
operating) at ambient
temperature: 30 °C (86
° F) and engine coolant
temperature: 90 ° – 100
° C 600 – 1000 kPa After longer than 10
min from A/C switch turned off
) A/C COMP CLUTCH Engine running. A/C switch and blower
motor switch turned ON
ON
A/C switch and/or blower
motor switch turned OFF OFF
) DFR INDICATOR Defroster indicator
lamp is lighted. ON
Defroster indicator la mp is not lighted. OFF
) VEHICLE SPEED At stop. OFF
0 km/h (0 mph)
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Scan Tool Data Definitions
TEMP CONT SWITCH (TEMPERATURE SELECTOR): Position of temperature control
selector of HVAC control module
CABIN TEMPERATURE: In-car temperature detected
by inside air temperature sensor installed in HVAC
control module
OUTSIDE AIR TEMP (OUTSIDE AIR TEMPERATURE): Outside air temperature
detected by outside air temperature sensor installed
in front bumper member
EVAPORATOR TEMP (EVAPORATOR TEMPERATURE): Temperature of air passed
through evaporator
COOLANT TEMP (ENGINE COOLANT TEMPERATURE): Engine coolant temperature
detected by engine coolant temperature sensor
SUN LOAD: Amount of sunlight detected by sunload
sensor installed on the driver side on the dashboard
MODE CONT SWITCH (MODE (AIR FLOW) SELECTOR): Position of air flow selector of HVAC
control module
FAN CONT SWITCH (BLOWER SPEED SELECTOR): Position of blower speed selector of HVAC control
module
FAN DESIRED VOLT: Voltage for blower motor AIR MIX POS SEN (TEMPERATURE CONTROL
ACTUATOR POSITI ON SENSOR): Input signal
from position sensor in temperature control actuator
MODE POS SENSOR (AIR FLOW CONTROL ACTUATOR POSITI ON SENSOR): Input signal
from position sensor in air flow control actuator
A/C CONT SIG (A/C SWITCH SIGNAL, ON or OFF): State of A/C switch
BLOWER LOAD SIG (BLO WER FAN LOAD SIGNAL,
ON or OFF): ON: Position of blower speed selector
is 1st position or more / OFF: Position of blower
speed selector is OFF position.
AIR INTAKE MODE (AUTO, FRE or REC): State of air
intake mode
REFRIGERANT PRESSURE (A/C REFRIGERANT ABSOLUTE PRESSURE): This parameter
indicates A/C refrigerant absolute pressure
calculated by ECM
A/C COMP CLUTCH (A/C COMPRESSOR MAGNET CLUTCH, ON or OFF): This parameter indicates
the state of the A/C switch
DFR INDICATOR (DEFROSTER INDICATOR LAMP, ON or OFF): State of defroster indicator lamp
VEHICLE SPEED: It is computed based on pulse
signals from vehicle speed sensor
Air Conditioning System CheckS7RS0B7224008
Step Action YesNo
1 Customer complaint analysis
1) Perform )”Customer complaint analysis”.
Was customer complaint analysis performed? Go to Step 2.
Perform customer
complaint analysis.
2 Visual inspection
1) Perform )“Visual inspection”.
Is there any faulty condition? Repair or replace
malfunction part.
Go to Step 3.
3 DTC check
1) Perform )“DTC check”.
Is there any DTC code? Go to Step 4.
Go to Step 5.
4 Troubleshooting malfunction
1) Perform ) “Troubleshooting malfunction”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 7.
Go to Step 5.
5 Perform A/C system symptom diagnosis
1) Inspect and repair referri ng to “A/C System Symptom
Diagnosis”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 7.
Go to Step 6.
6 Check for intermittent problem
1) Check for intermittent troubles referring to “Intermittent
and Poor Connection Inspection in Section 00”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 7.
Go to Step 7.
7 Final confirmation test
1) Perform ) “Final confirmation test”.
Is there any malfunction code? Go to Step 4.
End.
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DTC Troubleshooting
DTC B1553: CAN Communication Signal MalfunctionS7RS0B7224021
DTC Detecting Condition and Trouble Area
DTC Troubleshooting
DTC B1557: Vehicle Speed Sensor Signal MalfunctionS7RS0B7224022
DTC Detecting Condition and Trouble Area
DTC TroubleshootingStep Action Yes No
1 Serial communication signal data check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Start engine and select “DATA LIST” mode on scan tool.
3) Check “Refrigerant Pressure”, “Vehicle Speed”, “Coolant Temp” and “Outside Air Temp” varies displayed on scan
tool.
Is displayed each va ries described varies in “Scan Tool
Data”? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
Go to Step 2.
2 Serial communication signal check
1) Connect connectors to BCM and HVAC control module.
2) Using oscilloscope, check that serial communication
signal is outputted referring to “Reference waveform
No.8” of “Inspection of BCM and its Circuits in Section
10B”.
Is serial communication signal outputted at “G37-11”
terminal of BCM connector? HVAC control module
faulty.
BCM (included in
junction block
assembly) faulty.
DTC detecting condition
Trouble area
HVAC control module receives error code fr om BCM continuously.• CAN communication circuit
• BCM (included in junction block assembly)
•ECM
• HVAC control module
Step Action YesNo
1 DTC check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Check ECM and BCM for DTC.
Is there DTC(s)? Go to applicable DTC
diag. flow.
Substitute a known-
good HVAC control
module and recheck.
DTC detecting condition
Trouble area
HVAC control module receives error code from BCM continuously. • VSS circuit
• VSS
• HVAC control module
Step Action YesNo
1 DTC check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Check ECM for DTC.
Is there DTC P0500? Go to “DTC P0480: Fan
1 (Radiator Cooling
Fan) Control Circuit in
Section 1A”.
Substitute a known-
good HVAC control
module and recheck.
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ECM Voltage Values Table for Relation of A/C Control
Repair Instructions
Operation Procedure for Refrigerant ChargeS7RS0B7226001
Refer to “Operation Procedure for Refrigerant Charge”.Terminal Wire Color Circuit Normal Value Condition
C37-14 GRY/RED Output of 5 V power
source 4.5 – 5.5 V Ignition switch turned ON
C37-15 BLK Ground for ECM Below 0.3 V Ignition switch turned ON
C37-24 LT GRN Engine coolant temp.
(ETC) sensor signal 3.3 – 3.8 V Ignition switch turned ON, ECT at 0
°C (32 ° F)
1.38 – 1.72 V Ignition switch turned ON, ECT at 50 °C (122 °F)
C37-30 BLK Ground for ECM Below 0.3 V Ignition switch turned ON
C37-55 ORN Ground for sensors Below 0.3 V Ignition switch turned ON
C37-58 BLK/ORN Ground for ECM Below 0.3 V Ignition switch turned ON E23-1 BLK/RED Main power supply 10 – 14 V Ignition switch turned ON
E23-3 RED CAN (high)
communication line
(active high signal)
for BCM and
combination meterRefer to “DTC P2101: Throttle Actu
ator Control Motor Circuit Range /
Performance in Section 1A”
E23-16 BLK/RED Main power supply 10 – 14 V Ignition switch turned ON
E23-18 WHT CAN (low)
communication line
(active low signal) for
BCM and
combination meterRefer to “DTC P2101: Throttle Actu
ator Control Motor Circuit Range /
Performance in Section 1A”
E23-19 BLU/WHT Electric load signal
for blower motor 10 – 14 V
Ignition switch turned ON, blower speed selector
OFF or between 1st and 5th position
0 – 1 V Ignition switch turned ON, blower speed selector
between 6th and HIGH position
E23-46 LT GRN Radiator fan relay
No.1 output 10 – 14 V
Ignition switch turned ON, engine coolant temp.:
below 95
°C (203 ° F), or A/C refrigerant pressure:
below 600 kPa (87 psi).
0 – 2 V Ignition switch turned ON, engine coolant temp.:
97.5
°C (207.5 °F) or higher, or A/C refrigerant
pressure: 1100 kPa (159.5 psi) or higher.
E23-47 GRY A/C compressor relay
output 10 – 14 V Engine running, A/C request signal high input
0 – 1 V Engine running, A/C request signal low input
E23-48 GRN Radiator fan relay
No.2 and No.3 output 10 – 14 V
Ignition switch turned ON, engine coolant temp.:
below 100
°C (212 °F), or A/C refrigerant
pressure: below 1200 kPa (174 psi).
0 – 2 V Ignition switch turned ON, engine coolant temp.:
102.5
°C (216.5 ° F) or higher, or A/C refrigerant
pressure: 1500 kPa (217.5 psi) or higher.
E23-55 RED A/C refrigerant
pressure sensor
signal 1.46 – 1.71 V
Engine running, A/C refrigerant pressure at 0.8
MPa (8.0 kg/cm
2) (A/C refrigerant pressure
measured by manifold gauge)
2.55 – 2.80 V Engine running, A/C refrigerant pressure at 1.6
MPa (16.0 kg/cm
2) (A/C refrigerant pressure
measured by manifold gauge)
E23-60 BRN/WHT Main power supply
relay output 10 – 14 V Ignition switch turned OFF
0 – 2 V Ignition switch turned ON