2008 SUZUKI SWIFT vehicle speed signal circuit

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DTC C1121 / C1123 / C1124: VSS Circuit FailureS7RS0B6304017
DTC C1121: No Vehicle Speed Signal (60 Seconds or More)
DTC C1123: No Vehicle Speed Signal (30 Seconds or More)
DTC C1124: Vehicle Speed Performance (Impossible Deceleration)
Wiring Diagram
DTC Detecting Condition and Trouble Area
M
BRNRED/
BLU
BLK
RED
E52-14
E52-12
E23-4
E23-26
E23-25 E51-1
E51-2
[A ]
12
3
4 5 67
89
11
10
12 13
141516
17 18 19 20
5V
PPL
E52-4
8
5
12V
E49-2BLK
12V
12V
6REDRED/ BLKWHT
7WHTWHT/BLKWHTBLK BLK
111
2
[B ]
9
LT GRN
/BLKE52-1 E49-1
GRNGRNWHTBLK
WHY
10
3
4
4
4
4
1 2
12
I7RS0B630009-01
[A]: Connector “E52” (viewed from harness side)
4. Fuse9. ABS/ESP® control module
[B]: Connector “E49” (viewed from harness si de)5. ECM 10. Individual circuit fuse box No.1
1. Main fuse box 6. Left-front wheel speed sensor11. Vehicle speed signal circuit
2. Ignition switch 7. Right-front wheel speed sensor 12. Engine speed signal circuit
3. Junction block assembly 8. P/S control module
DTC detecting condition Trouble area
DTC C1121:
Vehicle speed signal is 0 km/h even though engine speed
is more than 4000 rpm for more than 60 seconds
continuously (before elapse of 5 min from engine start) or
vehicle speed signal is 0 km/h even though engine speed
is more than 2500 rpm for more than 60 seconds
continuously (after elapse of 5 min for engine start).
(1 driving cycle detection logic but MIL does not light up)
DTC C1123:
Vehicle speed signal is 0 km/h with continuously more
than 3 driving cycles even though engine speed is more
than 4000 rpm for more than 30 seconds continuously
(before elapse of 5 min from engine start) or vehicle speed
signal is 0 km/h with continuously more than 3 driving
cycles even though engine speed is more than 2500 rpm
for more than 30 seconds continuously (after elapse of 5
min for engine start).
(3 driving cycle detection logic)
DTC C1124:
Vehicle speed signal is less than 5 km/h for more than 5
seconds continuously with more than specified
deceleration speed (–20 m/s
2) from over 20 km/h.
(1 driving cycle detection logic but MIL does not light up) • Vehicle speed signal circuit
• Wheel speed sensor
•ECM
• P/S control module
• ABS/ESP®
control module
• CAN communication circuit

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DTC TroubleshootingStep Action Yes No 1 Was “EPS System Check” performed? Go to Step 2. Go to “EPS System
Check”.
2 DTC check
DTC Check for ECM referring to “DTC Check in Section 1A”.
Is there any DTC detected? Go to applicable DTC
diag. flow.
Go to Step 3.
3 DTC check
1) Check ABS control module for DTC referring to “DTC
Check in Section 4E”.
Is there any DTC detected? Go to applicable DTC
diag. flow.
Go to Step 4.
4 Vehicle speed signal circuit check
1) With ignition switch turned OFF, disconnect connectors
from ECM.
2) Check ECM connector for proper connection.
3) If OK, turn ON ignition switch, measure voltage between “E23-25” wire terminal of ECM connector and body
ground.
Is voltage 4 – 5 V? Go to Step 6.
Go to Step 5.
5 Vehicle speed signal circuit check
1) With ignition switch turned OFF, disconnect P/S control
module connector “E52”.
2) Check for proper terminal connection to P/S control module connector and ECM connector.
3) If connections are OK, chec k that “Vehicle speed signal
circuit” is as following.
• Insulation resistance of “Vehicle speed signal circuit” wire harness is infinity between its terminal and other
terminals at ECM and P/S control module connector.
• Wiring resistance of “Vehicle speed signal circuit” is less than 1 Ω.
• Insulation resistance of “Vehicle speed signal circuit” between its 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 circuit in good condition? Replace P/S control
module.
Repair or replace
defective circuit.
6 ECM voltage check
1) Connect P/S control mo dule and ECM connectors.
2) Check ECM for vehicle speed signal output referring to “Inspection of ECM and Its Circuits in Section 1A”.
Is check result in good condition? Replace P/S control
module.
Replace ECM.

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DTC C1122: Engine Speed SignalS7RS0B6304018
NOTE
DTC C1122 (engine speed signal failure) is indicated when ignition switch is at ON position and engine
is not running, but means there is nothing abnormal if indication changes to a normal one when
engine is started.

Wiring Diagram
Refer to “DTC C1121 / C1123 / C1124: VSS Circuit Failure”.
DTC Detecting Condition and Trouble Area DTC 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
• Vehicle speed signal circuit

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DTC TroubleshootingStep Action Yes No 1 Was “EPS System Check” performed? Go to Step 2. Go to “EPS System
Check”.
2 DTC check
1) Clear DTC(s) referring to “DTC Clearance”.
2) Run engine at idle speed.
3) Check if any DTC is detecte d referring to “DTC Check”.
Is DTC C1122 still detected? Go to Step 3. Check intermittent
trouble referring to
“Intermittent and Poor
Connection Inspection
in Section 00”.
3 DTC check
1) Check ECM for DTC referring to “DTC Check in Section
1A”.
Is there any DTC related to engine speed? Go to applicable DTC
diag. flow.
Go to Step 4.
4 Engine 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 “E52-12” wire terminal of P/S control module connector
and vehicle body ground.
Is voltage 10 – 14 V? Go to Step 6.
Go to Step 5.
5 1) With ignition switch turned OFF, disconnect ECM connector.
2) Check for proper connection to the P/S control module and ECM at each “Engine speed signal circuit” terminal.
3) If connections are OK, chec k that “Engine speed signal
circuit” is as following.
• Insulation resistance of “Engine speed signal circuit” wire is infinity between its terminal and other terminals
at ECM and P/S control module connector.
• Wiring resistance of “Engine speed signal circuit” terminal are less than 1 Ω.
• Insulation resistance of “Engine speed signal circuit” between its terminal 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 circuit in good condition? Go to Step 6.
Repair engine speed
signal circuit.
6 ECM voltage check
1) Connect P/S control mo dule and ECM connectors.
2) Check ECM for engine speed signal and vehicle speed signal output voltage to P/S control module referring to
“Inspection of ECM and Its Circuits in Section 1A”.
Is check result in good condition? Substitute a known-
good P/S control
module and recheck.
Substitute a known-
good ECM and recheck.

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Voltage Check1) Remove console box.
2) Check for voltage at each terminal with co nnectors connected to the P/S control module.
NOTE
As each terminal voltage is affected by the battery voltage, confirm if the battery voltage is 11 V or
more when ignition switch is ON.
*: The voltage of this circuit may not be checked by voltmeter. If so, use oscilloscope.

Terminal Wire colorCircuit Normal voltage Remarks
E49-1 GRN Main power supply for
internal memory and P/S
motor 10 – 14 V
—
E49-2 BLK Ground for P/S control
module Below 0.3 V
—
E51-1 BLK Motor output 1 *0 – 1 V
↑↓
10 – 14 V
(“Reference
waveform No.1: ”, “Reference
waveform No.2:
”and “Reference
waveform No.3: ”) • Engine idling and steering wheel at
straight position
• Voltage between “E51-1” and vehicle body ground
E51-2 RED Motor output 2 *0 – 1 V
↑↓
10 – 14 V
(“Reference
waveform No.1: ”, “Reference
waveform No.2: ” and “Reference
waveform No.3: ”) • Engine idling and steering wheel at
straight position
• Voltage between “E51-2” and vehicle body ground
E52-1 LT GRN/BLK Ignition switch signal for P/S
control module 10 – 14 V Ignition switch ON
E52-2 — —— —
E52-3 — —— —
E52-4 PPL Vehicle speed signal *0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.9”
under “Inspection of
ECM and Its Circuits in Section 1A”.) • Ignition switch ON
•Front left tire tu
rned quickly with right
tire locked
E52-5 GRY “EPS” warning light 0 V “EPS” warning light OFF
E52-6 BLU Torque sensor signal (Sub) About 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 – 6 V • Steering wheel with right turn
• Out put voltage varies linearly
depending on steering force
E52-7 — —— —
E52-8 GRN Main power supply for torque
sensor About 12 V• Ignition switch ON
• Check voltage between “E52-8” and
“E52-9” terminals
E52-9 BRN Ground for torque sensors Below 0.3 V —
E52-10 — —— —

Downloaded from www.Manualslib.com manuals search engine 7-ii Table of Contents
Recommended Service Material ....................... 7B-33
Special Tool ...................................................... 7B-33
Automatic Type .................... .................................7B-34
Precautions.........................................................7B-34 A/C System Caution .......................................... 7B-34
Precautions in Diagnosing Trouble ................... 7B-34
Precautions on Servicing A/C System .............. 7B-34
General Description .......... .................................7B-34
Auto A/C System Descript ion ............................ 7B-34
HVAC Control Module Operation Description ... 7B-36
Refrigerant Type Identifica tion .......................... 7B-36
Sub-Cool A/C System Description .................... 7B-36
A/C Operation Description ................................ 7B-36
On-Board Diagnostic System Description ......... 7B-37
Schematic and Routing Diagram ......................7B-37 Major Components of A/C System .................... 7B-37
A/C System Wiring Diagra m ............................. 7B-38
Diagnostic Information and Procedures ..........7B-39 A/C System Symptom Diagnosis ...................... 7B-39
Abnormal Noise Sympto m Diagnosis of A/C
System ............................................................ 7B-42
DTC Check........................................................ 7B-42
DTC Clearance ................................................. 7B-43
DTC Table ......................................................... 7B-44
Fail-Safe Table ................. ................................. 7B-45
Scan Tool Data ................................................. 7B-46
Air Conditioning System Check......................... 7B-47
Visual Inspection ............................................... 7B-49
DTC B1502: Inside Air Temperature Sensor and/or Its Circuit Malfunction .......................... 7B-49
DTC B1503: A/C Evaporator Air Temperature Sensor and/or Its Circuit Malfunction .............. 7B-50
DTC B1504: Sunload Sensor and/or Its Circuit Malfunction ......... ................................. 7B-52
DTC B1511: Temperature Control Actuator (Position Sensor) and/or Its Circuit
Malfunction ...................................................... 7B-53
DTC B1512: Air flow Control Actuator (Position Sensor) and/or Its Circuit
Malfunction ...................................................... 7B-55
DTC B1513: Temperature Control Actuator and/or Its Circuit Malfunction .......................... 7B-57
DTC B1514: Air Flow Co ntrol Actuator and/or
Its Circuit Malfunction ...................................... 7B-60
DTC B1541: HVAC Control Module Back-Up Power Supply Malfunction .............................. 7B-62
DTC B1546: A/C Refrigerant Pressure Malfunction ...................................................... 7B-63
DTC B1551: Serial Communication Circuit Malfunction ...................................................... 7B-63
DTC B1552: Serial Communication Signal Malfunction ...................................................... 7B-64
DTC B1553: CAN Communication Signal Malfunction ...................................................... 7B-65
DTC B1557: Vehicle Speed Sensor Signal Malfunction ...................................................... 7B-65
DTC B1561: Engine Coolant Temperature Sensor Signal Malfunctio n .............................. 7B-66 DTC B1562: Outside Air Temperature Sensor
Signal Malfunction ........................................... 7B-66
DTC B1563: A/C Refr igerant Pressure
Sensor Signal Malfunction .............................. 7B-66
Inspection of HVAC Control Module and Its Circuit .............................................................. 7B-67
A/C System Performance Inspection ................ 7B-70
A/C System Inspection at ECM ......................... 7B-70
Repair Instructions ............ ................................7B-71
Operation Procedure for Refrigerant Charge .... 7B-71
HVAC Unit Components ................................... 7B-72
HVAC Unit Removal and In stallation ................ 7B-73
Temperature Control Actuator Removal and Installation ....................................................... 7B-73
Temperature Control Actuat or Inspection ......... 7B-73
Air Flow Control Actuator Removal and Installation ....................................................... 7B-74
Air Flow Control Actuator Inspection ................. 7B-74
Air Intake Control Actuator Removal and Installation ....................................................... 7B-75
Air Intake Control Actuator Inspection............... 7B-75
Actuator Linkage Inspection .............................. 7B-76
Blower Motor Controller Removal and Installation ....................................................... 7B-76
Blower Motor Controller Inspection ................... 7B-76
HVAC Control Module Removal and Installation ....................................................... 7B-77
Sunload Sensor Removal and Installation ........ 7B-77
Sunload Sensor Inspection ............................... 7B-77
Outside Air Temperature Sensor Removal and Installation ................................................ 7B-77
Outside Air Temperature Sensor Inspection ..... 7B-77
Inside Air Temperature Sensor Removal and Installation ....................................................... 7B-78
Inside Air Temperature Sens or Inspection ........ 7B-78
Condenser Assembly On-Vehicle Inspection .... 7B-78
Condenser Assembly Removal and Installation ....................................................... 7B-78
Receiver/Dryer Removal and Installation .......... 7B-78
Evaporator Inspection ....................................... 7B-78
Evaporator Temperature Sensor Removal and Installation ................................................ 7B-78
Evaporator Temperature Se nsor Inspection ..... 7B-78
Expansion Valve Removal an d Installation ....... 7B-78
Expansion Valve Inspection .............................. 7B-78
A/C Refrigerant Pressure Sensor and Its Circuit Inspection............................................. 7B-78
A/C Refrigerant Pressu re Sensor Removal
and Installation ................................................ 7B-78
Compressor Relay Inspection .
.......................... 7B-78
Compressor Drive Belt Inspection and Adjustment ...................................................... 7B-78
Compressor Drive Belt Removal and Installation ....................................................... 7B-79
Compressor Assembly Removal and Installation ....................................................... 7B-79
Compressor Assembly Components................. 7B-79
Magnet Clutch Removal and Installation........... 7B-79
Magnet Clutch Inspection.................................. 7B-79
Relief Valve Inspection...................................... 7B-79

Downloaded from www.Manualslib.com manuals search engine 7B-44 Air Conditioning System: Automatic Type
3) Light over sunload sensor vertically with an incandescent lamp approximately 100 W apart from
about 100 mm (3.94 in.).
NOTE
If sunload sensor is not lighted over with an
incandescent lamp, DTC B1504 is detected
as current DTC even though there is not any
malfunction.

4) Turn ignition switch to ON position.
5) Erase DTC according to instructions 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 clearance, turn ignition switch to OFF position, and then di sconnect SUZUKI scan
tool from DLC.
Not Using SUZUKI Scan Tool 1) Turn ignition switch to ON position.
2) Set temperature selector to 25 °C (77 °F). 3) Push AUTO switch (1) and
MODE (air flow) selector
(2) at the same time to have history DTC displayed.
4) Push MODE (air flow) selector (2) and OFF switch (3) at the same time while history DTC is displayed.
5) Check that “CL” (4) appears on display. “CL” means that DTC has been cleared.
DTC TableS7RS0B7224005
CAUTION!
Be sure to perform “Air Conditioning Sy stem Check” before starting diagnosis.

1
2
3
2
4
I5RS0A722008-01
DTC No.
(displayed on
SUZUKI
scan tool) DTC
(indicated on
display of HVAC
control
module) Priority of
display
(current DTC) Priority
of
display
(history DTC) Diagnosis
“AUTO”
indicator lamp
) B1502 21 1 1 Inside air temperature sensor and/or its
circuit malfunction Open
Flashed
22 2 2 Short
) B1503 31 3 3 Evaporator temperature sensor and/or its
circuit malfunction Open
Flashed
32 4 4 Short
) B1504 41 21 — Sunload sensor and/or its circuit
malfunction Open —
42 5 5 Short Flashed
) B1511 61 6 6 Temperature control actuator (position
sensor) and/or its circuit malfunction Open
Flashed
62 7 7 Short
) B1512 71 8 8 Air flow control actuator (position sensor)
and/or its circuit malfunction Open
Flashed
72 9 9 Short
) B1513 63 10 10 Temperature control actuator and/or its circuit malfunction Flashed
) B1514 73 11 11 Air flow control actuator and/or its circuit malfunction Flashed
) B1541 E1 12 — HVAC control module back-up power supply malfunction —
) B1546 d5 22 — A/C refrigerant pressure malfunction —
) B1551 91 13 12
Serial communication circuit malfunction Open
Flashed
92 14 13 Short
) B1552 94 15 14 Serial communication signal malfunction Flashed
) B1553 A4 16 15 CAN communication signal malfunction Flashed
) B1557 b4 19 16 Vehicle speed sensor signal malfunction —
) B1561 54 17 17 Engine coolant temperature sensor signal malfunction Flashed

Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Automatic Type 7B-45
NOTE
When no current DTC is detected, all contents displayed on display (1) of HVAC control module and
defroster indicator (2) flash at the same time.

Fail-Safe TableS7RS0B7224006
When any of the following malfunctions (DTCs) is detected, fail-safe mode is activated.
However, when HVAC control module detects normal ope ration of A/C system, fail-safe mode is cancelled.
)
B1562 14 18 18 Outside air temperatur e sensor signal malfunction Flashed
) B1563 d4 20 19 A/C refrigerant pressure sensor signal malfunction —
— See NOTE
below
(current DTC) ——Normal —
00 (history DTC)
DTC No.
(displayed on
SUZUKI
scan tool) DTC
(indicated on
display of HVAC
control
module) Priority of
display
(current DTC) Priority
of
display
(history DTC) Diagnosis
“AUTO”
indicator lamp
1
2
I5RS0A722009-01
DTC No.
Trouble Area Fail-Safe Operation
)
B1502 Inside air temperature sensor and/
or its circuit HVAC control module controls actu
ators assuming that inside air
temperature is 25 ° C (77 °F).
)
B1503 A/C evaporator temperature sensor
and its circuit • HVAC control module turn
s off A/C switch signal.
• HVAC control module controls actu ators assuming that evaporator
temperature is 0 ° C (32 °F).
)
B1504 Sunload sensor and/or its circuit HVAC control module controls actu
ators assuming that amount of
sunlight is 0 W/m
2.
) B1551 Serial communication circuit
HVAC control module controls actuators assuming that outside air
temperature is 20 ° C (68 °F), engine coolant temperature is 80 °C
(176 °F), and vehicle speed is 40 km/h (25 mph).
)
B1552 Serial communication circuit
)
B1553 CAN communication circuit
)
B1557 Vehicle speed sensor and/or its
circuit HVAC control module controls act
uators assuming that vehicle speed
is 40 km/h (25 mph).
)
B1561 Engine coolant temperature sensor
and/or its circuit HVAC control module controls act
uators assuming that engine coolant
temperature is 80 ° C (176 °F).
)
B1562 Outside air temperature sensor
and/or its circuit HVAC control module controls actu
ators assuming that outside air
temperature is 20 ° C (68 °F).