2008 SUZUKI SWIFT Wheel control

Downloaded from www.Manualslib.com manuals search engine 6C-2 Power Assisted Steering System:
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

Downloaded from www.Manualslib.com manuals search engine 6C-4 Power Assisted Steering System:
Schematic and Routing Diagram
EPS System Wiring Circuit DiagramS7RS0B6302001
M
5V
BRNRED/
BLU
BLK
RED
WHT
BLU
GRN
BRN YEL
E52-11
E52-14E52-12
E23-4
E23-26
E23-25 E51-1
E51-2
E52-18
E53-5
E53-7
E52-6
E52-8
E53-2
E52-9
E52-16
E52-19
GRY
PPL/WHT
[A ]
[E ]
12 3
4 5 67
89
11
10
12 13
141516
17 18 19 20
1
2
[B ][C ]
1210 9 8 7654 3 21
16 15 14 13 12 11
26 25 24 2322 21 20 19 18 17
32 31 30 29 28 27
[D]
5V
PPL
E52-4
11
12
13 14
15
10
9
16
12V
5V
5V
12V
REDE52-20E53-6
E53-4
E53-1
7654321
5
REDRED/
BLKWHT
6WHTWHT/BLKWHTBLK
12V
12V
17BLK
GRY
LT GRN
/BLK
E52-1
E52-5
E49-1
GRNGRNWHTBLK
WHY
G28-25G28-31
RED/BLK
18
3
4
4
7 8
4
4
1 2
4
E49-2BLK
I7RS0B630002-01
[A]: Connector “E52” (viewed from harness side) 4. Fuse 12. P/S motor
[B]: Connector “E49” (viewed from harness side ) 5. Left-front wheel speed sensor 13. Shield
[C]: Connector “E51” (viewed from harness side) 6 . Right-front wheel speed sensor 14. Torque sensor
[D]: Connector “G28” (viewed from harness side) 7. Combination meter 15. Torque sensor amplifier
[E]: Connector “E53” (viewed from harness side) 8. “EPS” warning light16. To ECM, BCM, Air bag SDM and ABS control module assembly
1. Main fuse box 9. Date link connector (DLC) 17. ABS/ESP ® control module
2. Ignition switch 10. ECM18. Individual circuit fuse box No.1
3. Junction block assembly 11. P/S control module

Downloaded from www.Manualslib.com manuals search engine 6C-8 Power Assisted Steering System:
Step 2: DTC Check, Record and Clearance
First, check DTC, referring to “DTC Check”. If DTC is
indicated, print it or write them down and then clear them
by referring to “DTC Clearance”. DTC indicates
malfunction that occurred in the system but does not
indicate whether it exists now or it occurred in the past
and the normal condition has been restored now. To
check which case applies, check the symptom in
question according to Step 5 and recheck DTC
according to Step 6 and 7.
Attempt to diagnose a trouble based on DTC in this step
only or failure to clear the DTC in this step will lead to
incorrect diagnosis, trouble diagnosis of a normal circuit
or difficulty in troubleshooting.
Step 3 and 4: Visual Inspection
As a preliminary step, be sure to perform visual check of
the items that support proper function of the P/S system
referring to “Visual Inspection”.
Step 5: Trouble Symptom Confirmation
Based on information obtained in “Step 1: Customer
Complaint Analysis: ” and “S tep 2: DTC Check, Record
and Clearance: ”, confirm trouble symptoms. Also,
reconfirm trouble symptom by performing test drive and
turning steering wheel fully to right and left at stopped
vehicle.
Step 6 and 7: Rechecking and Record of DTC
Refer to “DTC Check” for checking procedure.
Step 8: Steering Symptom Diagnosis and P/S
System Symptom Diagnosis
Perform basic steering system check according to
“Steering Symptom Diagnosis in Section 6A” first. When
the end of the flow has been reached, check the parts of
the system suspected as a possible cause referring to
“P/S System Symptom Diagnosis” and based on
symptoms appearing on the vehicle (symptoms obtained
through steps of customer complaint analysis, trouble
symptom confirmation and/or basic P/S system check)
and repair or replace faulty parts, if any.
Step 9: Troubleshooting for DTC (See each DTC
Diag. Flow)
Based on the DTC indicated in Step 6 or 7 and referring
to the applicable DTC diag. flow, locate the cause of the
trouble, namely in a sensor, switch, wire harness,
connector, actuator, P/S control module or other part and
repair or replace faulty parts.
Step 10: Intermittent Problems Check
Check parts 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 DTC recorded in Step 2. Step 11: Final Confirmation Test
Confirm that the problem symptom has gone and the P/
S system is free from any abnormal conditions. If what
has been repaired is related to the DTC, clear the DTC
once, perform DTC confirmation procedure and confirm
that no DTC is indicated.
“EPS” Warning Light CheckS7RS0B6304002
1) Turn ignition switch to ON position (without engine
running) and chec k if the “EPS” warning light (1)
lights up. If the light dose not light up, go to ““EPS”
Warning Light Does Not Come ON with Ignition
Switch Turned ON before Engine Starts” of the
diagnostic flows.
2) Start engine and check if the “EPS” warning light turns OFF. If light remains ON and no DTC is stored
in P/S control module, go to ““EPS” Warning Light
Remains ON Steady after Engine Starts” for
troubleshooting.
DTC CheckS7RS0B6304003
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
1
I6RS0C630002-01
(A)
1
I4RS0B450003-01

Downloaded from www.Manualslib.com manuals search engine 6C-10 Power Assisted Steering System:
) 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

Downloaded from www.Manualslib.com manuals search engine Power Assisted Steering System: 6C-11
Scan Tool DataS7RS0B6304006
NOTE
When P/S motor is cold condition (that is, armature coil of P/S motor is not heated), normal value with
asterisk (*) mark in the following table is displayed on scan tool.

) C1143 P/S motor circuit current too
high Measured motor drive current is
more than 50 A.
• P/S motor circuit
• P/S motor
• P/S control module1 driving
cycle
) C1145 P/S motor circuit current too
low Measured motor drive current is
less than 2 A continuously for
more than 3 seconds even though
target motor drive current is more
than 4 A.
or
Measured motor drive current is
less than 0.8 A for total 1 second
even though motor control duty is
more than 90% while target motor
drive current is less than 8 A. 1 driving
cycle
) C1153 P/S control module power
supply circuit Power supply voltage of P/S
control module is less than 9 V for
5 seconds continuously. • P/S control module power
supply circuit
• Undercharged Battery
• P/S control module 1 driving
cycle
) C1155 P/S control module internal
failure Internal memory (EEPROM) is
data error.
• P/S control moduleNot
applicable
Internal circuit is faulty.
or
Power supply voltage of P/S
control module exceeded 17.5 V. • Overcharged Battery
• P/S control module
1 driving
cycle
DTC No. Detecting item
Detecting condition
(DTC will set when detecting) Trouble area MIL
Scan tool data
Vehicle conditionNormal condition
) Battery Voltage
Ignition switch ON 10 – 14 V
) TQS Power Supply 10 – 14 V
) TQS Main Torque Engine running at idle speed Steering wheel at fully turned to left –9.4 – 0 N
⋅m
Steering wheel at free 0 N⋅m
Steering wheel at fully turned to right 0 – 9.4 N ⋅m
) TQS Sub Torque Engine running at idle speed Steering wheel at fully turned to left –9.4 – 0 N
⋅m
Steering wheel at free 0 N⋅m
Steering wheel at fully turned to right 0 – 9.4 N ⋅m
) Assist Torque Engine running at idle speed Steering wheel at fully turned to left –9.4 – 0 N
⋅m
Steering wheel at free 0 N⋅m
Steering wheel at fully turned to right 0 – 9.4 N ⋅m
) Motor Control Engine running at idle speed Steering wheel at free
0 A
Steering wheel at fully turned to left or right *35 – 45 A
) Motor Monitor Engine running at idle speed Steering wheel at free
0 A
Steering wheel at fully turned to left or right *35 – 45 A
) Vehicle Speed Engine running and vehicle at stop 0 km/h
) Engine Speed Engine running at idle speed after warming up 700 ± 50 rpm
) Motor Volt Engine running at idle speed Steering wheel at free
0.8 – 1 V
Steering wheel at fully turned to right About 5 V
) Ignition switch Ignition switch ON ON

Downloaded from www.Manualslib.com manuals search engine 6C-12 Power Assisted Steering System:
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”.

Downloaded from www.Manualslib.com manuals search engine 6C-26 Power Assisted Steering System:
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

Downloaded from www.Manualslib.com manuals search engine Power Assisted Steering System: 6C-35
Inspection of P/S Control Module and Its CircuitsS7RS0B6304023
The P/S control module (1) and its circuits can be checked at the P/S control module wiring couplers (2) by measuring
voltage and resistance.
CAUTION!
P/S control module cannot be checked by itself. It is strictly prohibited to connect voltmeter or
ohmmeter to the P/S control module with connectors disconnected from the P/S control module.

5 P/S control module ground circuit check
1) Connect connectors to P/S control module.
2) Start engine.
3) Measure voltage between “E49-2” terminals of P/S
control module connector and body ground when
steering wheel fully turned to left or right.
Is voltage 0.3 V or less? P/S Control Module
Power Supply and
Ground Circuit is in
good condition.
“BLK” wire is open or
high resistance circuit.
Step Action Yes No
[A]
12
3
4 5 67
89
11
10
12 13
141516
17 18 19 20
[B]
[C]
12
1
1 2
2
I6RS0C630016-03
[A]: Connector “E52” (viewed from harness side) [C]: Connector “E49” (viewed from harness side)
[B]: Connector “E51” (viewed from harness side)