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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
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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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Serial Data Link Circuit CheckS7RS0B6304009
CAUTION!
Be sure to perform “EPS System Check” before starting “Troubleshooting”.
Wiring DiagramVehicle pulls to one side
during straight driving
Poor performance of torque sensor
Check torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering gear case assembly faulty Replace.
Poor recovery after turns Poor performance of torque sensor Check torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering column faulty Replace.
Abnormal noise P/S motor (built in steering gear case
assembly) malfunction Replace steering gear case assembly.
No idle up P/S control module faulty Check P/S control module referring to
“Inspection of P/S Control Module and Its
Circuits”.
Condition Possible cause Correction / Reference Item
MBLK
RED
E52-11 E51-1
E51-2PPL/WHT
[A ]
12
3
4 5 67
89
11
10
12 13
141516
17 18 19 2010 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
[C]
8
79
12V
[B ]
11
12
GRY
LT GRN
/BLK
E52-1
E52-5
E49-1
GRNGRNWHTBLK
WHY
G28-25G28-31
RED/BLK
10
3
4
4
5 6
4
4
1 2
4
E49-2BLK
I7RS0B630003-01
[A]: Connector “E52” (viewed from harness side) 3. Junction block assembly 8. P/S control module
[B]: Connector “E49” (viewed from harness side) 4. Fuse 9. T o ECM, BCM, Air bag SDM control module and ABS control
module assembly
[C]: Connector “G28” (viewed from harness side) 5. Comb ination meter 10. Individual circuit fuse box No.1
1. Main fuse box 6. “EPS” warning light 11. Serial data circuit
2. Ignition switch 7. Date link connector (DLC)
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“EPS” Warning Light Does Not Come ON with Ignition Switch Turned ON before Engine StartsS7RS0B6304010
Wiring Diagram
Circuit Description
Operation (ON/OFF) of “EPS” warning light is controlled by P/S control module through combination meter.
If the P/S system is in good condition, P/S control module turns “ EPS” warning light ON at the ignition switch ON, and
then turns it OFF at the engine start. If an abnormality in the system is detected, “EPS” warning light is turned ON
continuously by P/S control module. If P/S control module is disconnected, “EPS” warning light is not turned ON.
Troubleshooting
MBLK
REDE51-1
E51-2
[A ]
12 3
4 5 67
89
11
10
12 13
141516
17 18 19 2010 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
[C]
7
12V
E49-2BLK
[B ]
1 2
GRY
LT GRN
/BLK
E52-1
E52-5
E49-1
GRNGRNWHTBLK
WHY
G28-25G28-31
RED/BLK
8
3
4
4
5 6
4
4
1 2
4
9
I7RS0B630004-01
[A]: Connector “E52” (viewed from harness side) 2. Ignition switch6. “EPS” warning light
[B]: Connector “E49” (viewed from harness side) 3. Junction block assembly7. P/S control module
[C]: Connector “G28” (viewed from harness si de)4. Fuse 8. Individual circuit fuse box No.1
1. Main fuse box 5. Combination meter9. “EPS” warning light circuit
StepAction YesNo
1 1) Turn ignition switch ON.
Do the other warning lights come on? Go to Step 2.
“GRN”, “RED/BLK” wire
circuit or circuit fuse for
combination meter open
or short to ground.
2 1) Check power supply circuit and ground circuit for P/S control module referring to “P/S Control Module Power
Supply and Ground Circuit Check”.
Is check result in good condition? Go to Step 3.
Repair or replace
defective circuit.
3 1) Remove combination meter and disconnect combination meter connector (“G28”) with ignition switch turned OFF.
2) Check for proper connection to the combination meter at “G28-31” terminal.
3) If OK, check voltage between “G28-31” (“RED/BLK” wire) terminal and body ground with ignition switch ON.
Is it 10 – 14 V? Go to Step 4.
“RED/BLK” wire circuit
open or short to ground.
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“EPS” Warning Light Remains ON Steady after Engine StartsS7RS0B6304011
Wiring Diagram
Refer to ““EPS” Warning Light Does Not Come ON with Ignition Switch Turned ON before Engine Starts”.
Circuit Description
Operation (ON/OFF) of “EPS” warning light is controlled by P/S c ontrol module through combination meter.
If the P/S system is in good condition, P/S control module tu rns “EPS” warning light ON at the ignition switch ON, and
then turns it OFF at the engine start. If an abnormality in the system is detected, “EPS” warning light is turned ON
continuously by P/S control module. If P/S control module is disconnected, “EPS” warning light is not turned ON.
Troubleshooting 4 1) Check for proper connection to the combination meter at
“G28-25” terminal and P/S control module at “E52-5”
terminal.
2) Measure resistance between the combination meter at “G28-25” terminal and the P/S control module at “E52-5”
terminal.
Is it infinite (
∞)? “EPS warning light
circuit” is open.
Go to Step 5.
5 1) Connect combination meter connector (“G28”) with ignition switch turned OFF.
2) Check for voltage between “E52-5” (“GRY” wire) terminal and body ground with ignition switch ON.
Is it 10 – 14 V? Replace the P/S control
module.
Replace the
combination meter.
Step
Action YesNo
Step Action YesNo
1 1) Check DTC referring to “DTC Check”.
Is there any DTC(s) (NO CODES on SUZUKI scan tool)? Go to applicable DTC
diag. flow.
Go to Step 2.
2 1) With ignition switch OFF, disconnect P/S control module connector (“E52”).
2) Check for proper connection to the P/S control module at “E52-5” terminal.
3) If OK, then turn ignition switch to ON position.
Does “EPS” warning light turn on? Go to Step 3.
Replace the P/S control
module.
3 1) With ignition switch turned OFF, remove combination meter and its connector.
2) Check for proper terminal connection to combination meter connector.
3) If connections are OK, ch eck that “EPS warning light
circuit” is as following.
• Insulation resistance of “EPS warning light circuit” wire is infinity between its terminal and each terminal
at combination meter connector.
• Wiring resistance of “EPS wa rning light circuit” wire is
less than 1 Ω.
• Insulation resistance of “EPS warning light circuit” wire is infinity between its terminal and vehicle body
ground.
Is circuit in good condition? Replace the
combination meter.
Repair EPS warning
light circuit.
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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)
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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 — —— —
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P/S Motor and Its Circuit InspectionS7RS0B6306013
1) Remove console box.
2) Disconnect motor connector (“E51”) from P/S control module with ignition switch OFF.
3) Check for resistance between terminals of motor connector (“E51”).
If check result is not as specified, replace steering
gear case assembly.
Motor circuit resistance
4) Check for continuity between terminal of motor connector (“E51”) and body ground.
If check result is not as specified, replace steering
gear case assembly.
Motor circuit resistance
5) Hoist vehicle.
6) Connect “E51” connector to P/S control module with ignition switch OFF position.
7) Using ammeter (2), check that P/S motor (1) current is as following table with id ling engine. If check result
is not satisfactory, check P/S control module
referring to “Inspection of P/S Control Module and Its
Circuits”. If OK, replace steering gear case
assembly.
Motor current at hoisted vehicle
“E51-1” and “E51-2” (For motor) About 1 Ω
“E51-2” and body ground No continuity
1. Connector “E51” (viewed from harness side)
E51
11 2
I6RS0C630025-01
Condition When
steering
wheel is left at straight
position: [A] When
steering
wheel is
turned left or right by turning
speed with
90° /sec: [B] When
steering
wheel is kept fully turned left or right
until it stops.: [C]
Motor
current Approx. 0 A Approx.
0 – 4 A Approx.
30 – 45 A
1
32
E51-1
E51-2
[C] [A]
[B] [B]
I6RS0C630022-01