section 9 SUZUKI SX4 2006 1.G Service Workshop Manual

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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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Diagnostic Information and Procedures
Air Conditioning System CheckS6RW0D7224001
Step Action Yes No
1Customer complaint analysis
1) Perform )”Customer complaint analysis”.
Was customer complaint analysis performed?Go to Step 2. Perform customer
complaint analysis.
2Visual inspection
1) Perform ) “Visual inspection”.
Is there any faulty condition?Repair or replace
malfunction part.Go to Step 3.
3DTC check
1) Perform ) “DTC check”.
Is there any DTC code?Go to Step 4. Go to Step 5.
4DTC troubleshooting
1) Perform ) “DTC Troubleshooting”.
Is there any faulty condition?Repair or replace
malfunction part, and go
to Step 7.Go to Step 5.
5A/C system performance inspection
1) Perform ) “A/C system performance inspection”.
Is there any faulty condition?Repair or replace
malfunction part, and go
to Step 8.Go to Step 6.
6Perform A/C system symptom diagnosis
1) Inspect and repair referring to “A/C System Symptom
Diagnosis”.
Is there any faulty condition?Repair or replace
malfunction part, and go
to Step 7.Go to Step 8.
7Check 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 8.Go to Step 8.
8Final confirmation test
1) Perform ) “Final confirmation test”.
Is there any malfunction code?Go to Step 4. End.

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Description for Each Step
Step 1. Customer complaint analysis
Talk to customer, and then record details of the problem.
Customer questionnaire (Example)
NOTE
The form is a standard sample. It should be modified according to conditions characteristic of each
market.

Step 2. Visual inspection
As a preliminary step, be sure to perform visual check of
the items that support proper function of the air
conditioning system referring to “Visual Inspection”.
Step 3. DTC check
Check DTC referring to “DTC Check”.
Step 4. DTC troubleshooting
Based on the DTC, perform an applicable DTC
diagnostic flow and locate the cause of the trouble,
namely in a sensor, wire harness, connector, actuator,
HVAC control module or other part and repair faulty
parts.
Step 5. A/C system performance inspection
Inspect A/C system suspected to be a possible cause
referring to “A/C System Performance Inspection”.Step 6. A/C system symptom diagnosis
Check any part or system suspected to be a possible
cause referring to “A/C System Symptom Diagnosis”.
Step 7. Check for intermittent problem
Check any part where an intermittent trouble is easy to
occur (e.g., wire harness, connector, etc.), referring to
“Intermittent and Poor Connection Inspection in Section
00” and related circuit of trouble cord recorded.
Step 8. Final confirmation test
Confirm if the problem symptom is troubleshoot and the
A/C system is free from any abnormal conditions. If there
existed DTC, clear the DTC. Then, check if the DTC is
still detected and if there is any other DTC.
I4RH01722014-01

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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”.

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Cool air does not come
out or insufficient cooling
(A/C compressor normal
operation)Insufficient or excessive charge of
refrigerantCheck the amount of refrigerant and system
for leaks.
Condenser cloggedCheck condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
A/C evaporator clogged or frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”.
Evaporator temperature sensor faultyCheck evaporator temperature sensor
referring to “Evaporator Temperature Sensor
Inspection”.
Expansion valve faultyCheck expansion valve referring to “Expansion
Valve Inspection”.
Desiccant cloggedCheck desiccant and cap with filter.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor faultyCheck compressor.
Air in A/C systemReplace condenser, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Air leaking from HVAC unit or air ductRepair as necessary.
Heater and ventilation system faultyCheck HVAC unit.
HVAC control module faultyCheck HVAC control module referring to
“Inspection of HVAC Control Module and Its
Circuit”.
Temperature control actuator faultyCheck temperature control actuator referring to
“Temperature Control Actuator and Its Circuit
Inspection”.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
Excessive compressor oil in A/C systemDrain excessive compressor oil from A/C
system circuit and compressor.
Cool air does not come
out only intermittentlyWiring connection faultyRepair as necessary.
Expansion valve faultyCheck expansion valve referring to “Expansion
Valve Inspection”.
Excessive moisture in A/C systemReplace condenser, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Excessive amount of refrigerantCheck the amount of refrigerant.
Cool air comes out only at
high speedCondenser cloggedCheck condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
Insufficient charge of refrigerantCheck the amount of refrigerant and system
for leaks.
Air in A/C systemReplace condenser, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Compressor faultyCheck compressor.
Cool air does not come
out only at high speedExcessive amount of refrigerantCheck the amount of refrigerant.
A/C evaporator frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”. Condition Possible cause Correction / Reference Item

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Abnormal Noise Symptom Diagnosis of A/C
System
S6RW0D7224003
Refer to “Abnormal Noise Symptom Diagnosis of A/C
System”.
DTC CheckS6RW0D7224004
Using SUZUKI Scan Tool
1) Turn ignition switch to OFF position.
2) Connect SUZUKI scan tool to data link connector
(DLC) (1) located on underside of instrument panel
at driver’s seat side.
Special tool
(A): SUZUKI scan tool3) Light over sunload sensor vertically with an
incandescent light of approximately 100 W apart
from about 100 mm (3.94 in.).
NOTE
If sunload sensor is not lighted over with an
incandescent light, DTC B1504 is detected
even though there is not any malfunction.

4) Turn ignition switch to ON position.
5) Read DTC displayed on SUZUKI scan tool.
NOTE
To know how to use SUZUKI scan tool, refer
to operator’s manual for SUZUKI scan tool.

6) After completing the check, turn ignition switch to
OFF position and disconnect SUZUKI scan tool from
data link connector (DLC). Insufficient air flow of
cooled airA/C evaporator clogged or frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”.
Air leaking from HVAC unit or air ductRepair as necessary.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
Wiring or grounding faultyRepair as necessary. Condition Possible cause Correction / Reference Item(A)
1I5RW0A722004-01

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DTC of A/C System detected by ECM
NOTE
When no DTC is detected, “FRE” [A] and “REC” [B] indicator lights on HVAC control module flash at
the same time in specific pattern.

Fail-Safe TableS6RW0D7224007
When any of the following malfunctions (DTCs) is detected, fail-safe mode is activated.
However, when HVAC control module detects normal operation of A/C system, fail-safe mode is canceled. DTC No. Detection itemDetecting condition
(DTC will set when detecting)MIL
P0481 Fan 2 Control Circuit
Refer to “Fail-Safe Table in Section 1A”. P0532A/C Refrigerant Pressure
Sensor Circuit Low
P0533A/C Refrigerant Pressure
Sensor Circuit High
H: ON a. About 3 seconds
L: OFF b. About 1 seconds
DTC No. Trouble AreaFail-Safe Operation
When ignition switch is turned ON
after malfunction is already detectedWhen malfunction is detected during
ignition switch is ON
) B1502Inside air temperature
sensor circuitHVAC control module maintains last
normal value.HVAC control module controls actuators
assuming that inside air temperature is
25 °C (77 °F).
) B1503A/C evaporator
temperature sensor
circuitHVAC control module assuming that
evaporator temperature is 0 °C (32 °F).• HVAC control module turns off A/C
switch signal.
• HVAC control module controls
actuators assuming that evaporator
temperature is 0 °C (32 °F).
) B1504 Sunload sensor circuitHVAC control module maintains last
normal value.HVAC control module controls actuators
assuming that amount of sunlight is 0 W/
m
2.
) B1520Temperature selector
malfunctionHVAC control module maintains last
normal value.HVAC control module controls actuators
assuming that setting of temperature
selector is 25 °C (77 °F) position.
) B1521Blower speed selector
malfunctionHVAC control module maintains last
normal value.HVAC control module controls actuators
assuming that setting of blower speed
selector is low (1st) position.
) B1522Air flow selector
malfunctionHVAC control module maintains last
normal value.HVAC control module controls actuators
assuming that setting of air flow selector
is DEF position.
[A]
[A]H
L
H
L [B]
[B]
baaba
baaba
I5RW0A722008-01

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DTC B1520 / B1521 / B1522: Temperature / Blower Speed / Air Flow Selector MalfunctionS6RW0D7224017
DTC Detecting Condition and Trouble Area
DTC Troubleshooting5Wire harness check
Check position sensor circuit of temperature control actuator
for condition referring to Step 2 of “DTC B1512: Air flow
Control Actuator (Position Sensor) and/or Its Circuit
Malfunction”.
Is it in good condition?Go to Step 6. Repair or replace.
6Air Flow control actuator check
1) Check air flow control actuator for performance referring
to “Air Flow Control Actuator and Its Circuit Inspection”.
Is it in good condition?Substitute a known-
good HVAC control
module and recheck.Replace air flow control
actuator. Step Action Yes No
DTC Detecting Condition Trouble Area
When internal malfunction is detected in the
HVAC control module.• Temperature selector included in HVAC control module (DTC
B1520)
• Blower speed selector included in HVAC control module (DTC
B1521)
• Air flow selector included in HVAC control module (DTC B1522)
Step Action Yes No
1Was “Air Conditioning System Check” performed?Go to Step 2. Go to “Air Conditioning
System Check”.
2DTC check
1) Clear DTC referring to “DTC Clearance”.
2) Recheck DTC.
Are DTC B1520, B1521 and/or B1522 still detected?Substitute a known
good HVAC control
module and recheck.Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.

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DTC B1541: Back-Up Power Supply Circuit MalfunctionS6RW0D7224018
Wiring Diagram
DTC Detecting Condition and Trouble Area
NOTE
When checking DTC after connecting battery cable, be sure to turn ignition switch from OFF to ON and
from ON to OFF at least once, or DTC B1541 will be detected.

DTC Troubleshooting
12V5V
WHTG20-7 2
31G201 2 3 4 5 6 7 8 9 10 11 12 13 14
15 16 17 18 19 20 21 24 23 22 25 26 27 28 29 30WHT/RED [B]
I7RW01722011-01
[B]: Back-up power supply circuit 2. Main fuse
1. HVAC control module 3. Circuit fuse
DTC Detecting Condition Trouble Area
• Back-up power supply voltage is lower than specified value continuously.
• When connect battery with vehicle and then, turn ignition switch to ON
position for first time.• Battery voltage supply circuit
• HVAC control module
Step Action Yes No
1Was “Air Conditioning System Check” performed?Go to Step 2. Go to “Air Conditioning
System Check”.
2DTC check
1) Turn ignition switch to ON position for 20 sec. or more.
2) Ignition switch turned OFF and connect scan tool to
DLC.
3) Turn ON ignition switch and check DTC.
Is there DTC B1541?Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
3Battery voltage supply circuit check
1) Disconnect connector from HVAC control module with
ignition switch turned OFF.
2) Check for proper connection to back-up power supply
circuit terminal of HVAC control module connector.
3) If OK, measure voltage between back-up power supply
circuit terminal of HVAC control module connector and
vehicle body ground.
Is voltage 10 – 14 V?Substitute a known-
good HVAC control
module and recheck.Back-up power supply
circuit is open or
shorted to ground.

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DTC Detecting Condition and Trouble Area
DTC TroubleshootingDTC detecting condition Trouble area
Serial communication signal is higher than or lower than specified value for
specified time continuously.• Back-up power supply circuit
• Serial communication circuit
•BCM
• Information display
• HVAC control module
Step Action Yes No
1Was “Air Conditioning System Check” performed?Go to Step 2. Go to “Air Conditioning
System Check”.
2Back-up power supply circuit fuse check
1) Check back-up power supply circuit fuse for blowing.
Is fuse(s) blown?Replace blown fuse and
check for short in back-
up power supply circuit.Go to Step 3.
3Wire harness check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from BCM, information display
and HVAC control module.
3) Check for proper connection to serial communication
circuit terminal of BCM, information display and HVAC
control module connectors.
4) If OK, check that serial communication circuit is as
follows.
• Wiring harness resistance of serial communication
circuit is less than 3 Ω
• Insulation resistance between serial communication
circuit terminal and vehicle body ground is Infinity
• Circuit voltage of serial communication circuit is 0 - 1
V with ignition switch turned ON
Are they in good condition?Go to Step 4. Serial communication
circuit is open, short or
high resistance.
4Serial communication signal check
1) Connect connectors to BCM and HVAC control module
with ignition switch turned OFF.
2) Turn ignition switch to ON position.
3) Check that serial communication signal is outputted from
BCM referring to “Voltage Check” under “Inspection of
BCM and Its Circuits in Section 10B”.
Is serial communication signal outputted?Replace information
display.Go to Step 5.
5Communication data check
1) Connect connector to information display with ignition
switch turned OFF.
2) Check that serial communication signal is outputted from
BCM referring to “Voltage Check” under “Inspection of
BCM and Its Circuits in Section 10B”.
Is serial communication signal outputted?Substitute a known-
good HVAC control
module and recheck.Substitute a known-
good BCM and recheck.