2006 SUZUKI SX4 BCM

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Manual A/C Electronic Input Output TableS6RW0D7211002
A/C Operation Description at ECMS6RW0D7211003
ECM controls the A/C compressor relay and condenser cooling fan relay according to signals from HVAC control unit,
A/C refrigerant pressure sensor, ECT sensor and evaporator temperature sensor. The A/C switch ON signal from
HVAC control unit is transmitted to ECM through BCM. For CAN communication system, refer to “CAN
Communication System Description in Section 1A”.
ECM turns ON the A/C compressor relay when the vehicle state satisfy conditions described below.
• A/C switch ON signal is inputted from HVAC control unit
• A/C refrigerant pressure is within specified range
• Evaporator temperature is within specified range
• Engine speed is within specified range
• Engine coolant temperature is lower than specified value
• Throttle opening is lower than specified value
• Vehicle is not in either state of starting or quick acceleration
• ECT sensor malfunction is not detected
• A/C refrigerant pressure sensor malfunction is not detected
Condenser Cooling Fan Relay Control
ECM turn ON the condenser cooling fan relay at the same time when ECM turn ON the A/C compressor relay.
ECM
BCM
A/C switch Air intake selector
A/C refrigerant pressure sensor
A/C evaporator temperature sensorCompressor relay
ECT sensor
Condensor cooling fan relay
*
Wheel speed sensor (VSS)
HVAC control unit
Blower motor Blower motor resistor
Air intake control actuator
*Blower speed selector
ABS control module
I6RW0C721001-01
*: CAN communication

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-5
A/C System Wiring DiagramS6RW0D7212002
[A]
7
WHT
GRN5YELBLK
3
G154-3
G154-4
G154-7
G154-8
G154-10
G154-13
G154-5
G154-6
G155-5
G155-2
G155-3
G155-7
G155-6
G155-1
G154-9
G154-14
BLK/WHT
YEL
BLU/WHT
RED
BRN
GRN/WHT
RED/BLK
RED
GRN
GRN/YEL
RED/YEL
RED/BLU
20
21
23 22
BLK/RED
6 2
MBLK/WHTBLK/YEL
M
11
4RED/YEL 1
E01-49
12
E01-16
GRY 13
12V
BLU/WHTE01-3510
E01-48
18
19RED/BLK
BLK/RED
BLK/RED
BRN/WHTE01-60
E01-1
E01-29BLK/WHT
M
BLU/YELBLK/YEL
5V5V 5V
WHT/BLK
9
ORN
14E01-36
C01-12C01-14GRY/REDRED/BLU
E01-41
RED/BLK
RED
WHT
8
BLK
BLK/ORN
BLU IG1
IG2
5V
17
28
29
31
2726 2524
16
16
30
34
33E01-4 E01-19WHTRED
C01-50C01-49WHTRED
32
LT GRN
C01-57
C01-2415
GRY/BLU5V
I6RW0C721002-01
[A]: Illumination control model 9. A/C refrigerant pressure
sensor18. Condenser cooling fan relay 27. Illumination light
1. Ignition switch 10. ECM 19. Condenser cooling fan motor 28. Rear defogger relay
2. Blower motor 11. Air intake control actuator 20. Blower speed selector 29. Rear defogger
3. HVAC control unit 12. Compressor relay 21. A/C switch 30. Main relay
4. Lighting switch 13. Compressor 22. Air intake selector 31. Tail light
5. Blower motor relay 14. Evaporator temperature
sensor23. Rear defogger switch 32. TCM
6. Blower motor resistor 15. ECT sensor 24. “A/C” indicator light 33. To other control module and DLC
7. Junction block assembly 16. To BCM 25. “REC” indicator light 34. ABS control module
8. BCM 17. Main fuse box 26. Rear defogger indicator

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-13
A/C System Symptom DiagnosisS6RW0D7214004
Condition Possible cause Correction / Reference Item
No cool air comes out (A/
C compressor does not
operate)No refrigerantPerform recovery, evacuation and charge
referring to “Operation Procedure for
Refrigerant Charge”.
Fuse blownCheck related fuses, and then check for short
circuit to ground.
A/C switch faultyCheck A/C switch referring to “A/C Switch
Inspection”.
Blower speed selector faultyCheck blower speed selector referring to
“Blower Speed Selector Inspection in Section
7A”.
Evaporator temperature sensor faultyCheck evaporator temperature sensor
referring to “Evaporator Temperature Sensor
Inspection”.
A/C refrigerant pressure sensor faultyCheck A/C refrigerant pressure sensor
referring to “A/C Refrigerant Pressure Sensor
and Its Circuit Inspection”.
Wiring or grounding faultyRepair as necessary.
ECM faultyCheck ECM referring to “A/C System
Inspection at ECM”.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Compressor faultyCheck compressor.
Compressor relay faultyCheck compressor relay referring to “A/C
System Relay Inspection”.
BCM faultyCheck BCM referring to “Inspection of BCM
and Its Circuits in Section 10B”.
No cool air comes out
(radiator cooling fan
motor does not operate)Fuse blownCheck related fuses, and then check for short
circuit to ground.
Wiring or grounding faultyRepair as necessary.
Condenser cooling fan relay faultyCheck condenser cooling fan motor relay
referring to “A/C System Relay Inspection”.
Condenser cooling fan motor faultyCheck condenser cooling fan motor referring to
“Condenser Cooling Fan Inspection”.
ECM faultyCheck ECM referring to “A/C System
Inspection at ECM”.
No cool air comes out
(blower motor does not
operate)Fuse blownCheck related fuses, and then check for short
circuit to ground.
Blower motor relay faultyCheck blower motor relay referring to “Blower
Motor Relay Inspection in Section 7A”.
Blower motor resistor faultyCheck blower motor resistor referring to
“Blower Motor Resistor Inspection in Section
7A”.
Blower speed selector faultyCheck blower speed selector referring to
“Blower Speed Selector Inspection in Section
7A”.
Wiring or grounding faultyRepair as necessary.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Automatic Type 7B-39
General Description
Auto A/C System DescriptionS6RW0D7221001
The automatic type air conditioning system (auto A/C) is provided with the function to automatically control the inside
air temperature, fan speed, air flow outlet direction and air intake position by HVAC control module in addition to
functions of the manual type air conditioning system (manual A/C). Once the inside air temperature is set using the
temperature selector, HVAC control module automatically controls the inside air temperature at the constant level at all
times based on the inside air temperature, outside air temperature, amount of sunlight and engine coolant
temperature detected respectively by the inside air temperature sensor, outside air temperature sensor, sunload
sensor and ECT sensor. For the electronic control system components location, refer to “Electronic Control System
Components Location”. For the A/C system components location, refer to “A/C System Major Components Location”.
Auto A/C Electronic Control Input / Output Table
Temperature selector
MODE (air flow) selector
Blower speed selector
Air intake selector
AUTO switch A/C switch
Outside air
temperature
sensor
A/C refrigerant pressure sensor
Compressor relay
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
Sunload sensor
Inside air temperature sensor
Evaporator temperature sensor
Condenser cooling fan relay
Wheel
speed
sensor
*
*
*
Combination meterABS control module
I6RW0C722001-01
*: CAN communication

Downloaded from www.Manualslib.com manuals search engine 7B-40 Air Conditioning System: Automatic Type
HVAC Control DescriptionS6RW0D7221002
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, ECT 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, ECT 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 air flow control
actuator so that the current air flow control 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)A/C Compressor Relay Control
HVAC control module outputs A/C switch ON signal to
ECM via BCM when the vehicle state satisfy conditions
described below.
• A/C switch is ON
• Evaporator temperature is higher than specified value
• Evaporator temperature sensor malfunction is not
detected
Communication of ECM and BCM is established by CAN
(Controller Area Network). (For more detail of CAN
communication, refer to “CAN Communication System
Description in Section 1A”).
ECM turns ON the A/C compressor relay when the
vehicle state satisfy conditions described below.
• A/C switch ON signal is inputted
• A/C refrigerant pressure is within specified range
• Engine speed is within specified range
• Engine coolant temperature is lower than specified
value
• Throttle opening is lower than specified value
• Vehicle is not in either state of starting or quick
acceleration
• ECT sensor malfunction is not detected
• A/C refrigerant pressure sensor malfunction is not
detected
Condenser Cooling Fan Relay Control
ECM turn ON the condenser cooling fan relay at the
same time when ECM turn ON the A/C compressor
relay.
Sub-Cool A/C System DescriptionS6RW0D7221003
Refer to “Sub-Cool A/C System Description”.

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On-Board Diagnostic System DescriptionS6RW0D7221004
NOTE
The diagnostic information as diagnostic
trouble code (DTC) can be known by using
SUZUKI scan tool. For further details, refer to
“DTC Check”.

HVAC control module detects malfunctions, which may
occur in the following area.
• Inside air temperature sensor
• Evaporator temperature sensor
• Sunload sensor
• Temperature control actuator
• Air flow control actuator
• Temperature selector of HVAC control module
• Air flow selector of HVAC control module
• Blower speed selector of HVAC control module
• Back-up power supply circuit of HAVC control module
• Serial communication line between BCM and HVAC
control module• Received data from BCM as follows
– Outside air temperature sensor signal
– ECT sensor signal
– A/C refrigerant pressure sensor signal
– VSS signal
– Engine type signal
– Combination meter spec signal
– CAN communication circuit failure signal
When HVAC control module detects malfunction, the “A/
C” indicator light (1) flashes to warn and the diagnostic
trouble code (DTC) is stored in the memory of the
module. When diagnosing trouble, the DTC can be
checked according to “DTC Check”.
Schematic and Routing Diagram
A/C System Air Flow DiagramS6RW0D7222001
Refer to “A/C System Air Flow Diagram”.
1
I5RW0A722002-01

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Automatic Type 7B-43
Component Location
A/C System Major Components LocationS6RW0D7223001
Refer to “A/C System Major Components Location”.
[A]: Illumination control model 10. Air intake actuator 22. Compressor 34. “A/C” indicator light
[B]: Junction block with BCM 11. Air flow control actuator 23. HVAC control module 35. Rear defogger switch
[C]: Junction block without BCM 12. Temperature control actuator 24. BCM 36. Rear defogger indicator
1. Main fuse box 13. Inside air temperature sensor 25. A/C refrigerant pressure sensor 37. To other control module
2. Ignition switch 14. Outside air temperature sensor 26. Condenser cooling fan relay 38. Indicator light, switch,
selector
3. CAN junction connector 15. Evaporator temperature sensor 27. Information display 39. “FRE” indicator light
4. Rear defogger relay 16. Sunload sensor 28. Lighting switch 40. “REC” indicator light
5. Rear defogger 17. Junction block assembly 29. A/C switch 41. Temperature selector
6. Blower motor relay 18. ECM 30. Air intake selector 42. Blower speed selector
7. Blower motor 19. ECT sensor 31. To BCM 43. MODE (air flow) selector
8. Blower motor controller 20. Condenser cooling fan motor 32. ABS control module 44. Tail light
9. DLC 21. Compressor relay 33. Illumination light 45. Main relay

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Automatic Type 7B-47
A/C System Symptom DiagnosisS6RW0D7224002
Condition Possible cause Correction / Reference Item
No cool air comes out (A/
C system does not
operate)No refrigerantPerform recovery, evacuation and charge
referring to “Operation Procedure for
Refrigerant Charge”.
Fuse blownCheck related fuses, and then check for short
circuit to ground.
A/C switch faultyCheck A/C switch referring to “Inspection of
HVAC Control Module and Its Circuit”.
Evaporator temperature sensor faultyCheck evaporator temperature sensor
referring to “Evaporator Temperature Sensor
Inspection”.
A/C refrigerant pressure sensor faultyCheck A/C refrigerant pressure sensor
referring to “A/C Refrigerant Pressure Sensor
and Its Circuit Inspection”.
Wiring or grounding faultyRepair as necessary.
ECM faultyCheck ECM referring to “A/C System
Inspection at ECM”.
HVAC control module faultyCheck HVAC control module referring to
“Inspection of HVAC Control Module and Its
Circuit”.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Compressor faultyCheck compressor.
Compressor relay faultyCheck compressor relay referring to “A/C
System Relay Inspection”.
BCM faultyCheck BCM referring to “Inspection of BCM
and Its Circuits in Section 10B”.
No cool air comes out
(radiator cooling fan
motor does not operate)Fuse blownCheck related fuses, and then check for short
circuit to ground.
Wiring or grounding faultyRepair as necessary.
Condenser cooling fan motor relay faultyCheck condenser cooling fan motor relay
referring to “A/C System Relay Inspection”.
Condenser cooling fan motor faultyCheck condenser cooling fan motor referring to
“Condenser Cooling Fan Inspection”.
ECM faultyCheck ECM referring to “A/C System
Inspection at ECM”.
HVAC control module faultyCheck HVAC control module referring to
“Inspection of HVAC Control Module and Its
Circuit”.
No cool air comes out
(blower motor does not
operate)Fuse blownCheck related fuses, and then check for short
circuit to ground.
Blower motor controller faultyCheck blower motor controller referring to
“Blower Motor Controller Inspection”.
HVAC control module faultyCheck HVAC control module referring to
“Inspection of HVAC Control Module and Its
Circuit”.
Wiring or grounding faultyRepair as necessary.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
Blower motor relay faultyCheck blower motor relay referring to “Blower
Motor Relay Inspection in Section 7A”.