2005 SUZUKI SWIFT speed signal

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Steeri ng
Power Assisted Steering System
Precautions
Steering System NoteS7RS0B6300001
NOTE
All steering gear fasteners are important attaching parts in that they could affect the performance of
vital parts and systems, and/or could result in major repair expense. They must be replaced with one of
the same part number or with an equivalent part if replacement becomes necessary. Do not use a
replacement part of lesser quality or substitute design. Torque values must be used as specified
during reassembly to assure proper retention of these parts.

Precautions in Diagnosing TroublesS7RS0B6300002
• Take a note of DTC indicated on the SUZUKI scan tool.
• Before inspection, be sure to read “Pre cautions for Electrical Circuit Service in Section 00” and understand what is
written there.
• DTC C1122 (engine speed signal failure) is indicated when ignition switch is at ON position and engine is not
running, but it means there is nothing abnormal if indica tion changes to a normal one when engine is started.
• As DTC is stored in memory of the P/S control module, be sure to clear memory after repair by performing the
procedure described in “DTC Clearance”.

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General Description
P/S System DescriptionS7RS0B6301001
This power steering (P/S) system consists of a P/S control module (3), a torque sensor (4), a motor (5). In this system,
the P/S control module determines the level and direction of the assist force for the steering wheel (1) according to the
signals from the torque sensor and vehicle speed signal from ECM. The P/S control module runs the motor so as to
assist the operation of the steering wheel.
The P/S control module diagnoses troubles which may occur in the area including the following components when the
ignition switch is ON and the engine is running. When the P/S control module detects any malfunction, it stops the
motor operation.
• Torque sensor
• Vehicle speed signal
• Engine speed signal
• P/S motor
• P/S control module.
2. Steering column 7. Battery9. ABS/ESP® control module
6. Steering gear case assembly 8. ECM10. Wheel speed sensor (right-front, left-front)
7
3
9
10
10
1
2
4
5
6
8
I7RS0B630001-01

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Terminal Arrangement of P/S Control Module Coupler (Viewed from Harness Side)
Diagnostic Information and Procedures
EPS System CheckS7RS0B6304001
WARNING!
Carry out test drive in light traffic area to prevent an accident.

Refer to the following items for the details of each step.Terminal Circuit Terminal Circuit
E49-1 Main power supply for internal memory
and EPS motor E52-9 Ground for torque sensors
E49-2 Ground for P/S control module E52-10 —
E51-1 Motor output 1 E52-11 Serial communication for data link
connector
E51-2 Motor output 2 E52-12 Engine speed signal
E52-1 Ignition switch signal for P/S control
module E52-13 —
E52-2 — E52-14 P/S operation signal (idle up signal)
E52-3 — E52-15 —
E52-4 Vehicle speed signal E52-16 Torque sensor internal failure signal
E52-5 “EPS” warning light E52-17 —
E52-6 Torque sensor signal (Sub) E52-18 Torque sensor signal (Main)
E52-7 — E52-19 Ground for shield wire
E52-8 Main power supply for torque sensor E52-20 5 V reference power supply for torque
sensor
Step
Action YesNo
1 ) Customer complaint analysis
1) Perform customer complaint analysis referring to “Customer Complaint Analysis”.
Was customer complaint analysis performed? Go to Step 2.
Perform customer
complaint analysis.
2 ) DTC check, record and clearance
1) Check for DTC (including pending DTC) referring to “DTC Check”, Record and Clearance.
Is there any DTC(s)? Print DTC or write them
down and clear them by
referring to “DTC
Clearance” and go to
St ep 3 .Go to Step 4.
3 ) Visual inspection
1) Perform visual inspection referring to “Visual Inspection”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 11.
Go to Step 5.
4 ) Visual inspection
1) Perform visual inspection referring to “Visual Inspection”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 11.
Go to Step 8.
5 ) Trouble symptom confirmation
1) Confirm trouble symptom referring to “Trouble Symptom Confirmation”.
Is trouble symptom identified? Go to Step 6.
Go to Step 7.
6 ) Rechecking and record of DTC
1) Recheck for DTC referring to “DTC Check”.
Is there any DTC(s)? Go to Step 9.
Go to Step 8.

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3) Start engine.
4) Read DTC according to the instructions displayed on
SUZUKI scan tool. For further details, refer to
operator’s manual for SUZUKI scan tool.
NOTE
• If communication between SUZUKI scan tool and the vehicle can not be
established, perform “Serial Data Link
Circuit Check”.
• DTC C1122 (engine speed signal failure) is indicated when ignition switch is at ON
position and engine is not running, but it
means there is nothing abnormal if
indication changes to a normal one when
engine is started.

5) After completing the check, turn ignition switch to
OFF position and disconnect SUZUKI scan tool from
DLC.
DTC ClearanceS7RS0B6304004
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 tool
3) Turn ignition switch to ON position.
4) Erase DTC according to the instructions displayed on SUZUKI scan tool. For further details, refer to
operator’s manual for SUZUKI scan tool.
5) After completing the clearance, turn ignition switch to OFF position and disconnect SUZUKI scan tool from
DLC.
DTC TableS7RS0B6304005
CAUTION!
Be sure to perform the “EPS Syst em Check” before starting troubleshooting corresponding to each
DTC.

(A)
1
I4RS0B450003-01
DTC No. Detecting item Detecting condition
(DTC will set when detecting) Trouble area MIL
No
CODES Normal — — —
) C1113 Steering torque sensor (Main
and Sub) circuit correlation Voltage difference between torque
sensor main signal and sub signal
is more than 0.6 V for 1 second
continuously. • Torque sensor signal circuit
• Torque sensor
• P/S control module
1 driving
cycle
) C1114 Steering torque sensor
reference power supply
circuit Circuit voltage of torque sensor 5
V reference power supply voltage
is more than 5.7 V or less than 4.3
V for 1 second continuously. • Torque sensor circuit
• Torque sensor
• P/S control module
1 driving
cycle
) C1117 Steering torque sensor
failure signal circuit low Torque sensor internal failure
signal circuit voltage is less than
1.7 V when ignition switch turned
ON.
• Torque sensor signal circuit
• Torque sensor
• P/S control module1 driving
cycle
) C1118 Steering torque sensor
failure signal circuit high Torque sensor internal failure
signal circuit voltage is more than
3.7 V for 1 second continuously. 1 driving
cycle
) C1119 Steering torque sensor
power supply circuit Circuit voltage of torque sensor
main power supply
is less than
7.5 V for 1 second continuously. • Torque sensor circuit
• Torque sensor
• P/S control module
1 driving
cycle

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) C1121 No vehicle speed signal
(60 seconds or more) 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). • Vehicle speed signal circuit
• Wheel speed sensor
•ECM
• P/S control module
• ABS control module
• CAN communication circuit
Not
applicable
) C1122 Engine speed signal 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.• Engine speed signal circuit
•ECM
• P/S control module
• Vehicle speed signal
1 driving
cycle
) C1123 No vehicle speed signal
(30 seconds or more) 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). • Vehicle speed signal circuit
• Wheel speed sensor
•ECM
• P/S control module
• ABS control module
• CAN communication circuit
3 driving
cycles
) C1124 Vehicle speed performance
(Impossible deceleration) 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. Not
applicable
) C1141 P/S motor circuit voltage Voltage between both motor drive
circuits is more than 8.5 V or less
than 0.2 V for 0.5 seconds
continuously while motor is not
drived.
• P/S motor circuit
• P/S motor
• P/S control module1 driving
cycle
) C1142 P/S motor circuit range /
performance Measured motor drive current is
more than 10 A as compared with
target motor drive current. 1 driving
cycle
DTC No. Detecting item
Detecting condition
(DTC will set when detecting) Trouble area MIL

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Scan Tool Data Definitions
Battery Voltage
This parameter indicates battery positive voltage.
TQS Power Supply (Torque Sensor Power Supply, V)
This parameter indicates the power supply voltage which
the P/S control module supplies to the torque sensor.
TQS Main Torque (Torque Sensor Main Torque, N ⋅m)
The torque sensor is installed to detect the steering force
and the steering directio n. It consists of two
potentiometers and the main torque sensor is one of
these.
TQS Sub Torque (Torque Sensor Sub Torque, N ⋅m)
The torque sensor is installed to detect the steering force
and the steering directio n. It consists of two
potentiometers and the sub-torque sensor is one of
these. Its output characteristics are compared with those
of the main torque sensor.
Assist Torque (N ⋅m)
This parameter is an internal parameter of the P/S
control module. It is obtained by computing the torque
sensor input signal. Motor Control (Motor Control Current, A)
Based on the input signal, the P/S control module
determines the assist amount
and controls the current to
the motor suitable for that a ssist amount. This parameter
indicates that control value.
Motor Monitor (Motor Monitor Current, A)
This parameter indicates the actually measured value of
the current flowing to the motor. The motor circuit
condition is diagnosed by co mparing this parameter with
“Motor Control” parameter described previously.
Vehicle Speed (km/h, MPH)
Vehicle speed signal is fed from BCM. P/S control
module determines the amount of power assist based on
this vehicle speed signal and the torque sensor signal.
Engine Speed (rpm)
Engine speed signal is fed from the ECM so that it can
be used for trouble diagnos is of the electric power
steering system.
Motor Volt (V)
This parameter indicates the voltage between motor
terminals.
Ignition switch (ON, OFF)
This parameter indicates the condition of the power
supply through the ignition switch.
Visual InspectionS7RS0B6304007
Visually check the following pats and system.
P/S System Symptom DiagnosisS7RS0B6304008
This section describes trouble diagnosis of the P/S system parts whose trouble is not indicated by the on-board
diagnostic system (self-diagnostic functi on). When no malfunction is indicated by the on-board diagnostic system
(self-diagnosis function) and those stee ring basic parts as described in “Steering Symptom Diagnosis in Section 6A”
are all in good condition, check the following power steer ing system parts which may be a possible cause for each
symptom of the steering. Inspection Item Referring section
Battery Level, leakage, color “Batte ry Description in Section 1J”
Connectors of electric wire
harness Disconnection friction “Intermittent and Poor
Connection Inspection in Section 00”
Fuses Burning “Cautions in Body Electric al System Servicing in Section 9A”
Parts Installation, damage
Other parts that can be checked visually
Condition Possible cause Correction / Reference Item
Steering wheel feels
heavy (Perform “Steering
Force Check” before
diagnosis.) Steering wheel installed improperly
(twisted)
Install steering wheel correctly.
Poor performance of torque sensor Check torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Poor performance of P/S motor Check motor referring to “P/S Motor and Its
Circuit Inspection”.
Steering gear case assembly faulty Replace.
Poor performance of vehicle speed
signal from ECM Check vehicle speed signal circuit referring to
“DTC C1121 / C1123 / C1124: VSS Circuit
Failure”.

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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.