
Downloaded from www.Manualslib.com manuals search engine 6C-24 Power Assisted Steering System:
DTC C1122: Engine Speed SignalS6RW0D6304015
Wiring Diagram6Vehicle speed signal circuit check
1) With ignition switch turned OFF, disconnect connectors
from BCM.
2) Check BCM connector for proper connection.
3) If OK, turn ON ignition switch, measure voltage between
“G04-15” or “G04-22” wire terminal of BCM connector
and body ground.
Is voltage 4 – 5 V?Go to Step 7. Go to Step 8.
7BCM voltage check
1) With ignition switch turned OFF, connect BCM
connector.
2) Check BCM for vehicle speed signal output referring to
“Inspection of P/S Control Module and Its Circuits”.
Is it in good condition?Replace P/S control
module.Replace BCM.
8Vehicle speed signal circuit check
1) Check that vehicle speed signal circuit is as follows.
• Insulation resistance of wire harness is infinity
between “Vehicle speed signal” terminal and other
terminal at P/S control module connector.
• Wiring harness resistance of “Vehicle speed signal”
circuit is less than 1Ω.
• Insulation resistance between “Vehicle speed signal”
circuit and vehicle body ground is infinity.
• Circuit voltage between “Vehicle speed signal” circuit
and ground circuit is 0 – 1 V with ignition switch turned
ON.
Is it in good condition?Replace P/S control
module.Repair or replace
defective circuit. Step Action Yes No
[A]
123
4567
8
9 11
10 12 13
141516
17 18 1920
1
2
[B]
BRN LT GRN/
BLK
E11-1
E11-12
E13-1 GRN
GRN
WHT
6
37
9
10
8
4 12
12V
E13-2BLK12V5
11
[C]E01-44E01-4
I6RW0D630004-01
[A]: P/S control module connector No.1 “E11” (viewed from harness side) 3. Junction block assembly 8. “IGN” fuse
[B]: P/S control module connector No.2 “E13” (viewed from harness side) 4. Main fuse 9. “P/S” fuse
[C]: M15A engine with 4A/T equipped with slip control model (Hong Kong model) 5. ECM 10. “IG1 SIG” fuse
1. Main fuse box 6. P/S control module 11. Engine speed signal circuit
2. Ignition switch 7. Individual circuit fuse box No.1

Downloaded from www.Manualslib.com manuals search engine Power Assisted Steering System: 6C-25
DTC Detecting Condition and Trouble Area
DTC TroubleshootingDTC detecting condition Trouble area
Engine speed signal is less than 220 rpm for more than
0.8 seconds.
or
Engine speed signal is less than 220 rpm for more than 20
seconds continuously even though vehicle speed signal is
more than 50 km/h.
(1 driving cycle detection logic)• Engine speed signal circuit
•ECM
• P/S control module
Step Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2DTC check
1) Check ECM for DTC referring to “DTC Check in Section
1A”.
Is there any DTC(s) detected?Go to applicable DTC
diag. flow.Go to Step 3.
3Engine speed signal circuit check
1) With ignition switch turned OFF, disconnect P/S control
module connector.
2) Check P/S control module connector for proper
connection.
3) If OK, turn ON ignition switch, measure voltage between
“E11-12” wire terminal of P/S control module connector
and vehicle body ground.
Is voltage 10 – 14 V?Go to Step 4. Go to Step 5.
4ECM voltage check
1) With ignition switch turned OFF, connect P/S control
module and ECM connectors.
2) Check engine speed signal output referring to
“Inspection of ECM and Its Circuits in Section 1A”.
Is it in good condition?Substitute a known-
good P/S control
module and recheck.Substitute a known
good ECM and recheck.
5Engine speed signal circuit check
1) Disconnect ECM connector.
2) Check that engine speed signal circuit is as follows.
• Insulation resistance of wire harness is infinity
between “Engine speed signal circuit” terminal and
other terminal at P/S control module connector.
• Wiring harness resistance of “Engine speed signal
circuit” is less than 1Ω.
• Insulation resistance between “Engine speed signal
circuit” and vehicle body ground is infinity
• Circuit voltage between “Engine speed signal circuit”
and ground circuit is 0 – 1 V with ignition switch turned
ON.
Is it in good condition?Substitute a known
good ECM and recheck.Repair or replace
defective circuit.

Downloaded from www.Manualslib.com manuals search engine Power Assisted Steering System: 6C-31
Terminal Wire color Circuit Normal voltage Condition
E11-1 LT GRN/BLKIgnition switch signal for P/S
control module10 – 14 V Ignition switch ON
E11-2 — — — —
E11-3 — — — —
E11-4 PPL Vehicle speed signal*0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.7”
under “Inspection
of BCM and Its
Circuits in
Section 10B”)• Ignition switch ON
• Front left tire turned quickly with right
tire locked
E11-5 GRY “EPS” warning light0 V Ignition switch ON
0 – 14 V Engine running
E11-6 — — — —
E11-7 — — — —
E11-8 GRN9 V power supply for torque
sensorAbout 9 V• Ignition switch ON
• Voltage between “E11-8” and “E11-9”
terminals
E11-9 BLK Ground for torque sensors — —
E11-10 WHT Torque sensor signal (Sub)About 2.5 – 4.0 V• Steering wheel with left turn
• Out put voltage varies linearly
depending on steering force
About 2.5 V Steering wheel at free
About 1.0 – 2.5 V• Steering wheel with right turn
• Out put voltage varies linearly
depending on steering force
E11-11 BLUSerial communication circuit for
data link connector——
E11-12 BRN Engine speed signal*0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.24
and No.25” under
“Inspection of
ECM and Its
Circuits in
Section 1A”)Engine idling
E11-13 — — — —
E11-14 RED/BLU P/S active signal (idle up signal)About 12 V Ignition switch ON
0 – 1 VEngine idling and turned steering wheel
to the right or left until it stops
E11-15 — — — —
E11-16 — — — —
E11-17 — — — —
E11-18 YEL Torque sensor signal (Main)About 1.0 – 2.5 V• Steering wheel with left turn
• Out put voltage varies linearly
depending on steering force
About 2.5 V Steering wheel at free
About 2.5 – 4.0 V• Steering wheel with right turn
• Out put voltage varies linearly
depending on steering force
E11-19 GRY Ground for shield wire — —

Downloaded from www.Manualslib.com manuals search engine Table of Contents 7- i
7
Section 7
CONTENTS
HVAC
Precautions ................................................. 7-1
Precautions............................................................. 7-1
Precautions on HVAC ........................................... 7-1
Heater and Ventilation............................. 7A-1
General Description ............................................. 7A-1
Heater and Ventilation Construction ................... 7A-1
Schematic and Routing Diagram ........................ 7A-2
Heater and Ventilation Wiring Circuit Diagram .... 7A-2
Component Location ........................................... 7A-2
Electronic Control System Components
Location ............................................................ 7A-2
Diagnostic Information and Procedures ............ 7A-3
Heater and Ventilation Symptom Diagnosis........ 7A-3
Repair Instructions .............................................. 7A-4
HVAC Unit Components ..................................... 7A-4
HVAC Unit Removal and Installation (Non-A/
C) ...................................................................... 7A-4
Blower Motor Removal and Installation............... 7A-4
Blower Motor Inspection ..................................... 7A-4
Blower Motor Resistor Removal and
Installation ......................................................... 7A-5
Blower Motor Resistor Inspection ....................... 7A-5
Blower Motor Relay Inspection ........................... 7A-6
HVAC Control Unit Components ......................... 7A-6
HVAC Control Unit Removal and Installation ...... 7A-7
Blower Speed Selector Inspection ...................... 7A-9
Air Intake Selector Inspection ............................. 7A-9
Air Intake Control Actuator Removal and
Installation ......................................................... 7A-9
Air Intake Control Actuator Inspection .............. 7A-10
Center Ventilation Louver Removal and
Installation ....................................................... 7A-11
Side Ventilation Louver Removal and
Installation ....................................................... 7A-11
Rear Duct Removal and Installation (If
Equipped)........................................................ 7A-12
HVAC Air Filter Removal and Installation (If
Equipped)........................................................ 7A-12
HVAC Air Filter Inspection (If Equipped) ........... 7A-12
Air Conditioning System......................... 7B-1
Manual Type ............................................................ 7B-1
Precautions........................................................... 7B-1A/C System Caution ............................................ 7B-1
Precautions on Servicing A/C System ................ 7B-1
General Description .............................................7B-2
Sub-Cool A/C System Description ...................... 7B-2
Manual A/C Electronic Input Output Table .......... 7B-3
A/C Operation Description at ECM ..................... 7B-3
Schematic and Routing Diagram ........................7B-4
A/C System Air Flow Diagram............................. 7B-4
A/C System Wiring Diagram ............................... 7B-5
Component Location ...........................................7B-6
A/C System Major Components Location ........... 7B-6
Electronic Control System Components
Location............................................................. 7B-7
Diagnostic Information and Procedures ............7B-8
A/C System Performance Inspection .................. 7B-8
Trouble Diagnosis for Abnormal Pressure ........ 7B-11
A/C System Inspection at ECM ......................... 7B-12
A/C System Symptom Diagnosis ...................... 7B-13
Abnormal Noise Symptom Diagnosis of A/C
System ............................................................ 7B-15
Repair Instructions ............................................7B-17
Operation Procedure for Refrigerant Charge .... 7B-17
Condenser Cooling Fan Removal and
Installation ....................................................... 7B-22
Condenser Cooling Fan Inspection ................... 7B-23
Condenser Assembly On-Vehicle Inspection .... 7B-23
Condenser Assembly Removal and
Installation ....................................................... 7B-23
Desiccant Removal and Installation .................. 7B-24
HVAC Unit Components ................................... 7B-25
HVAC Unit Removal and Installation ................ 7B-26
Evaporator Inspection ....................................... 7B-27
Evaporator Temperature Sensor Removal
and Installation ................................................ 7B-27
Evaporator Temperature Sensor Inspection ..... 7B-28
Expansion Valve Removal and Installation ....... 7B-28
Expansion Valve Inspection .............................. 7B-28
A/C Refrigerant Pressure Sensor and Its
Circuit Inspection............................................. 7B-29
A/C Refrigerant Pressure Sensor Removal
and Installation ................................................ 7B-29
A/C Switch Inspection ....................................... 7B-29
A/C System Relay Inspection............................ 7B-30
Compressor Drive Belt Inspection and
Adjustment ...................................................... 7B-30

Downloaded from www.Manualslib.com manuals search engine 7-ii Table of Contents
Compressor Drive Belt Removal and
Installation ....................................................... 7B-31
Compressor Assembly Removal and
Installation ....................................................... 7B-31
Compressor Assembly Components................. 7B-32
Magnet Clutch Inspection.................................. 7B-32
Magnet Clutch Removal and Installation........... 7B-33
Thermal Switch Inspection ................................ 7B-35
Thermal Switch Removal and Installation ......... 7B-35
Relief Valve Inspection...................................... 7B-36
Relief valve Removal and Installation ............... 7B-36
Specifications .....................................................7B-37
Tightening Torque Specifications ...................... 7B-37
Special Tools and Equipment ...........................7B-37
Recommended Service Material ....................... 7B-37
Special Tool ...................................................... 7B-37
Automatic Type .....................................................7B-38
Precautions.........................................................7B-38
A/C System Caution .......................................... 7B-38
Precautions in Diagnosing Trouble ................... 7B-38
Precautions on Servicing A/C System .............. 7B-38
General Description ...........................................7B-39
Auto A/C System Description ............................ 7B-39
HVAC Control Description................................. 7B-40
Sub-Cool A/C System Description .................... 7B-40
On-Board Diagnostic System Description ......... 7B-41
Schematic and Routing Diagram ......................7B-41
A/C System Air Flow Diagram........................... 7B-41
A/C System Wiring Diagram ............................. 7B-42
Component Location .........................................7B-43
A/C System Major Components Location ......... 7B-43
Electronic Control System Components
Location .......................................................... 7B-44
Diagnostic Information and Procedures ..........7B-45
Air Conditioning System Check......................... 7B-45
A/C System Symptom Diagnosis ...................... 7B-47
Abnormal Noise Symptom Diagnosis of A/C
System ............................................................ 7B-49
DTC Check........................................................ 7B-49
DTC Clearance ................................................. 7B-51
DTC Table ......................................................... 7B-52
Fail-Safe Table .................................................. 7B-54
Scan Tool Data ................................................. 7B-55
Visual Inspection ............................................... 7B-57
DTC B1502: Inside Air Temperature Sensor
Circuit Malfunction .......................................... 7B-57
DTC B1503: Evaporator Temperature Sensor
Circuit Malfunction .......................................... 7B-59
DTC B1504: Sunload Sensor Circuit
Malfunction ...................................................... 7B-60
DTC B1511: Temperature Control Actuator
(Position Sensor) and/or Its Circuit
Malfunction ...................................................... 7B-61
DTC B1512: Air flow Control Actuator
(Position Sensor) and/or Its Circuit
Malfunction ...................................................... 7B-63
DTC B1513: Temperature Control Actuator
(Motor) and/or Its Circuit Malfunction .............. 7B-65DTC B1514: Air Flow Control Actuator (Motor)
and/or Its Circuit Malfunction........................... 7B-67
DTC B1520 / B1521 / B1522: Temperature /
Blower Speed / Air Flow Selector
Malfunction ...................................................... 7B-68
DTC B1541: Back-Up Power Supply Circuit
Malfunction ...................................................... 7B-69
DTC B1546: A/C Refrigerant Pressure
Malfunction ...................................................... 7B-70
DTC B1551: Serial Communication Circuit
Malfunction ...................................................... 7B-70
DTC B1552: HVAC Control Module Check
Sum Error ........................................................ 7B-72
DTC B1553: CAN Communication Circuit
Malfunction ...................................................... 7B-72
DTC B1557: VSS Signal Failure ....................... 7B-73
DTC B1561: ECT Signal Failure ....................... 7B-73
DTC B1562: Outside Air Temperature Signal
Failure ............................................................. 7B-74
DTC B1563: A/C Refrigerant Pressure Signal
Failure ............................................................. 7B-74
DTC B1570: Engine Type Signal Failure .......... 7B-75
DTC B1571: Combination Meter Spec Signal
Failure ............................................................. 7B-75
Inspection of HVAC Control Module and Its
Circuit .............................................................. 7B-76
A/C System Inspection at ECM ......................... 7B-79
Repair Instructions ............................................7B-79
Operation Procedure for Refrigerant Charge .... 7B-79
HVAC Unit Components ................................... 7B-80
HVAC Unit Removal and Installation ................ 7B-81
Temperature Control Actuator Removal and
Installation ....................................................... 7B-81
Temperature Control Actuator and Its Circuit
Inspection ........................................................ 7B-81
Air Flow Control Actuator Removal and
Installation ....................................................... 7B-83
Air Flow Control Actuator and Its Circuit
Inspection ........................................................ 7B-83
Air Intake Actuator Removal and Installation .... 7B-84
Air Intake Actuator Inspection ........................... 7B-84
Actuator Linkage Inspection.............................. 7B-84
Blower Motor Controller Removal and
Installation ....................................................... 7B-84
Blower Motor Controller Inspection ................... 7B-85
HVAC Control Module Removal and
Installation ....................................................... 7B-85
Sunload Sensor Removal and Installation ........ 7B-85
Sunload Sensor Inspection ............................... 7B-86
Outside Air Temperature Sensor Removal
and Installation ................................................ 7B-86
Outside Air Temperature Sensor Inspection ..... 7B-86
Inside Air Temperature Sensor Removal and
Installation ....................................................... 7B-86
Inside Air Temperature Sensor Inspection ........ 7B-86
Condenser Cooling Fan Relay Inspection......... 7B-87
Condenser Cooling Fan Removal and
Installation ....................................................... 7B-87
Condenser Cooling Fan Inspection ................... 7B-87
Condenser Assembly On-Vehicle Inspection .... 7B-87

Downloaded from www.Manualslib.com manuals search engine 7A-2 Heater and Ventilation:
Schematic and Routing Diagram
Heater and Ventilation Wiring Circuit DiagramS6RW0D7102001
Non–A/C
Manual A/C
Refer to “A/C System Wiring Diagram in Section 7B”.
Auto A/C
Refer to “A/C System Wiring Diagram in Section 7B”.
Component Location
Electronic Control System Components LocationS6RW0D7103001
Refer to “Electronic Control System Components Location in Section 7B” (non-A/C and manual A/C) or “Electronic
Control System Components Location in Section 7B” (auto A/C).
5V
BLK
RED/BLK3
5 72
G154-3
G154-4
G154-7
G154-8
G154-10
G154-13
G155-2
G155-3
G155-7
G155-6
G155-1
G154-9
G154-14
BLK/WHT
YEL
BLU/WHT
RED
RED/BLKRED
GRN
GRN/YEL
RED/YEL
RED/BLU
BLK/ORN
46
8
BLU
YELGRN
WHT
13
1514
[A]21
BLK/RED
12V
BLK/YELBLK/WHTM
BLK
1IG1
IG2
12
BLK/RED
M 10
11
11
BLU/WHT 19
16
17
18 9 20
I6RW0C710003-01
[A]: Illumination control model 6. Blower motor resistor 12. Main fuse box 18. Illumination light
1. Ignition switch 7. Junction block assembly 13. Blower speed selector 19. Rear defogger relay
2. Blower motor 8. BCM 14. Air intake selector 20. Rear defogger
3. HVAC control unit 9. ECM 15. Rear defogger switch 21. Tail light
4. Lighting switch 10. Air intake control actuator 16. “REC” indicator light
5. Blower motor relay 11. To BCM 17. Rear defogger indicator

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-3
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
![SUZUKI SX4 2006 1.G Service Workshop Manual 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
G15 SUZUKI SX4 2006 1.G Service Workshop Manual 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
G15](/manual-img/20/7612/w960_7612-944.png)
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