Eps SUZUKI SX4 2006 1.G Service Service Manual

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Visual InspectionS6RW0D6304006
Visually check the following parts and systems.)
C1141P/S motor circuit
voltageVoltage between both motor
drive circuit is more than 8.5 V or
less than 0.2 V for 0.5 second
continuously while motor is not
driven.
• P/S motor circuit
• P/S motor
• Torque sensor
• P/S control module1 driving
cycle1 driving
cycle
)
C1142P/S motor circuit range/
performanceMeasured motor drive current is
more than 10 A as compared
with target motor drive current.1 driving
cycle1 driving
cycle
)
C1143P/S motor circuit
current too highMeasured motor drive current is
more than 65 A.1 driving
cycle1 driving
cycle
)
C1145P/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% when target
motor drive current is less than 8
A.1 driving
cycle1 driving
cycle
)
C1153P/S control module
power supply circuitPower supply voltage of P/S
control module is less than 9 V
for 5 seconds continuously while
engine speed is more than 600
rpm• P/S control module
power supply circuit
• Undercharged Battery
• Generator
• P/S control module1 driving
cycle1 driving
cycle
)
C1155P/S control module
internal failureInternal memory (EEPROM) is
data error.• P/S control module1 driving
cycleDoes not
light up
Internal circuit is faulty.
or
Power supply voltage of P/S
control module exceeded 17.5 V• Generator
• P/S control module1 driving
cycle1 driving
cycle DTC No. Detecting itemDetecting condition
(DTC will set when detecting)Trouble area DTC“EPS”
warning
light
Inspection Item Referring section
Battery Level, leakage, color “Battery Description in Section 1J”
Connectors of
electric wire harnessDisconnection friction“Intermittent and Poor Connection Inspection in
Section 00”
Fuses Burning“Cautions in Body Electrical System Servicing in
Section 9A”
Parts Installation, damage
Other parts that can be checked visually

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Motor Drive Voltage (V)
This parameter indicates the voltage between motor
terminals.
System Power Status (EPS System Power, ON, OFF)
This parameter indicates input status of EPS system
power supply.
IGN switch Status (ON, OFF)
This parameter indicates the condition of the power
supply through the ignition switch.Torque sensor Status (ON, OFF)
This parameter indicates the output status of the torque
sensor power supply.
Fail Safe FET Status (ON, OFF)
This parameter indicates the status of the motor drive
power supply circuit.
P/S System Symptom DiagnosisS6RW0D6304008
This section describes trouble diagnosis of the P/S system parts whose trouble is not indicated by the on-board
diagnostic system (self-diagnostic function). When no malfunction is indicated by the on-board diagnostic system
(self-diagnosis function) and assuredly those steering basic parts as described in “Steering Symptom Diagnosis in
Section 6A” are all in good condition, check the following power steering system parts which may be a possible cause
for each symptom of the steering.
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 P/S motorCheck P/S motor referring to “P/S Motor and
Its Circuit Inspection”.
Poor performance of torque sensorCheck torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering gear case assembly
malfunctionReplace steering gear case assembly.
Poor performance of vehicle speed
signal from BCMCheck vehicle speed signal circuit referring to
“DTC C1121 / C1123 / C1124: Vehicle Speed
Signal Circuit Failure”.
Steering wheel feels
heavy momentarily when
turning it to the left or
rightSteering gear case assembly
malfunctionReplace steering gear case assembly.
Poor recovery from turnsPoor performance of torque sensorCheck torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering gear case assembly
malfunctionReplace steering gear case assembly.
Vehicle pulls to one side
during straight drivingPoor performance of torque sensorCheck torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering gear case assembly
malfunctionReplace steering gear case assembly.
Abnormal noiseP/S motor (built in steering gear case
assembly) malfunctionReplace steering gear case assembly.
No idle upP/S control module faultyCheck P/S control module referring to
“Inspection of P/S Control Module and Its
Circuits”.

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DLC and Its Communication Check (No communication to P/S Control Module)S6RW0D6304009
Wiring Diagram
Troubleshooting
[A]
123
4567
8
9 11
10 12 13
141516
17 18 1920
1
2
[B]
10 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]
LT GRN/BLKE11-1
E11-11
E13-1 GRN
GRN
WHT
8
13
318
19
20
5
6 17
4
12
712V
E13-2BLK
9
G241-31
+BB
BLU/
WHTE04-9
10
11
RED/BLK
G241-25E11-5GRY
L313-312
BLKBLK/
ORN
16
16
15
14[D]
I6RW0D630002-01
[A]: P/S control module connector No.1 “E11” (viewed from harness side) 5. Combination meter 13. Individual circuit fuse box No.1
[B]: P/S control module connector No2 “E13” (viewed from harness side) 6. “EPS” warning light 14. Serial data circuit
[C]: Combination meter connector “G241” (viewed from harness side) 7. Data link connector (DLC) 15. DLC power supply circuit
[D]: Junction block without BCM model (Taiwan model) 8. P/S control module 16. DLC ground circuit
1. Main fuse box 9. BCM 17. “IGN” fuse
2. Ignition switch 10. To HVAC control module 18. “P/S” fuse
3. Junction block assembly 11. To ABS control module 19. “IG1 SIG” fuse
4. Main fuse 12. To SDM 20. “MTR” fuse
Step Action Yes No
1“EPS” warning light check
1) Turn ignition switch to ON position.
Does “EPS” warning light turn on?Go to step 2. Go to ““EPS” Warning
Light Does Not Come
ON with Ignition Switch
Turned ON before
Engine Starts”.
2Scan tool condition check
1) Make sure that SUZUKI scan tool is as follows.
• Correct PCMCIA card (software) is used.
• There are no deformation and wear for DLC cable
terminals.
• Connection for DLC cable terminals is in good
condition.
Are they OK?Go to step 3. Repair or replace
defective part.

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“EPS” Warning Light Does Not Come ON with Ignition Switch Turned ON before Engine StartsS6RW0D6304010
Wiring Diagram8Scan tool operation check
1) Check if communication is possible by making
communication with other vehicles.
Is it possible to communicate with the other vehicle?Scan tool is in good
condition, check
intermittent trouble
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.Recheck PCMCIA card
and DLC cable for faulty
condition. If they are
OK, scan tool is faulty. Step Action Yes No
[A]
123
4567
8
9 11
10 12 13
141516
17 18 1920
1
2
[B]
10 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]
LT GRN/BLKE11-1E13-1 GRNGRN
WHT
7
8
311
12
13
5
6 10
4 12
12V
E13-2BLK
G241-31
RED/BLK
G241-25E11-5GRY
9
I6RW0C630003-01
[A]: P/S control module connector No.1 “E11” (viewed from harness side) 4. Main fuse 10. “IGN” fuse
[B]: P/S control module connector No.2 “E13” (viewed from harness side) 5. Combination meter 11. “P/S” fuse
[C]: Combination meter connector “G241” (viewed from harness side) 6. “EPS” warning light 12. “IG1 SIG” fuse
1. Main fuse box 7. P/S control module 13. “MTR” fuse
2. Ignition switch 8. Individual circuit fuse box No.1
3. Junction block assembly 9. “EPS” warning light circuit

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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
Step Action Yes No
1“EPS” warning light power supply check
1) Turn ignition switch ON.
Do the other warning light come on?Go to Step 2. “GRN”, “RED/BLK” wire
circuit or circuit fuse for
combination meter is
open or short to ground.
2Fuse check
1) Turn ignition switch OFF.
2) Remove and inspect circuit fuse for P/S control module.
Is fuse in good condition?Reinstall fuse, and then
go to Step 3.Check “GRN” wire
circuit for short to
ground.
If OK, replace fuse.
3P/S control module power supply and ground circuit
check
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 4. Repair or replace
defective circuit.
4Combination meter power supply circuit check
1) Remove combination meter and disconnect combination
meter connector (“G241”) with ignition switch turned
OFF.
2) Check for proper connection to the combination meter at
“G241-31” terminal.
3) If OK, check voltage between “G241-31” (“RED/BLK”
wire) terminal and body ground with ignition switch ON.
Is it 10 – 14 V?Go to Step 5. “RED/BLK” wire circuit
is open or short to
ground.
5“EPS” warning light circuit resistance check
1) Check for proper connection to the combination meter at
“G241-25” terminal and P/S control module at “E11-5”
terminal.
2) Check that “EPS warning light circuit” is as follows.
• Insulation resistance of “EPS warning light circuit”
wire is infinity between its terminal and each terminal
at combination meter connector.
• Wiring resistance of “EPS warning 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?“GRY” wire circuit is
open.Go to Step 6.
6“EPS” warning light circuit voltage check
1) Connect combination meter connector (“G241”) with
ignition switch turned OFF.
2) Check for voltage between “E11-5” (“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.

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“EPS” Warning Light Remains ON Steady after Engine StartsS6RW0D6304011
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 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
Step Action Yes No
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“EPS” warning light circuit check
1) With ignition switch turned OFF, disconnect P/S control
module connector.
2) Check for proper connection to the P/S control module at
“E11-5” terminal.
3) If OK, then turn ignition switch to ON position.
Does “EPS” warning light turn ON?Go to Step 3. Replace P/S control
module.
3Combination meter ground circuit check
1) Remove combination meter and disconnect combination
meter connector with ignition switch turned OFF.
2) Check combination meter connector for proper
connection.
3) If connections are OK, check that “EPS warning light
circuit” is as follows.
• Insulation resistance of “EPS warning light circuit”
wire is infinity between its terminal and each terminal
at combination meter connector.
• Insulation resistance of “EPS warning light circuit”
wire is infinity between its terminal and vehicle body
ground.
Is circuit in good condition?Replace combination
meter.Repair defective circuit.

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DTC Troubleshooting
Step Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2DTC check
Is DTC C1153 or C1116 indicated, together?Go to applicable diag.
flow.Go to Step 3.
3Torque sensor signal circuit check
1) With ignition switch turned OFF, disconnect torque
sensor connector.
2) Check for voltage between following terminal with
ignition switch ON.
• “E11-18” (“YEL” wire) terminal and body ground
• “E11-10” (“WHT” wire) terminal and body ground
Is it about 0 V?Go to Step 4. Torque sensor signal
circuit is shorted to
other circuit.
4Torque sensor circuit check
1) Disconnect P/S control module connector.
2) Check that torque sensor signal circuit is as follows.
• Insulation resistance of wire harness is infinity
between “Torque sensor signal circuit” terminal and
other terminal at torque sensor connector.
• Wiring harness resistance of “Torque sensor signal
circuit” is less than 1 Ω.
• Insulation resistance between “Torque sensor signal
circuit” and vehicle body ground is infinity.
Is circuit in good condition?Go to Step 5. Repair or replace
defective circuit.
5Torque sensor check
1) Connect connectors to P/S control module and torque
sensor with ignition switch turned OFF.
2) Check torque sensor out put voltage referring to “Torque
Sensor and Its Circuit Inspection”.
Is torque sensor in good condition?Substitute a known-
good P/S control
module and recheck.Go to Step 6.
6P/S control module resistance check
1) With ignition switch turned OFF, disconnect torque
sensor connector.
2) Check for resistance between following terminal with
ignition switch ON.
• “E11-18” (“YEL” wire) terminal and body ground
• “E11-10” (“WHT” wire) terminal and body ground
Is it about 1 k
Ω?Replace steering gear
case.Replace P/S control
module.

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DTC C1116: Steering Torque Sensor Power Supply CircuitS6RW0D6304013
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Troubleshooting
[A]
123
453 21
4
5
67
8
9 11
10 12 13
141516
17 18 1920
1
2
[B]
[C]
LT GRN/
BLK
WHT GRN
BLK
E11-1
E11-10E11-8
E11-9
E11-19
E13-1 GRN
GRY
GRN
WHT
5
6
37
10
11
9
4 12
12V
E13-2BLK
9V
REDE11-20
5VYELE11-18E31-5
E31-2
E31-39V
E31-43V
E31-1
8
I6RW0C630005-02
[A]: P/S control module connector No.1 “E11” (viewed from harness side) 3. Junction block assembly 8. Torque sensor power supply circuit
[B]: P/S control module connector No.2 “E13” (viewed from harness side) 4. Main fuse 9. “IGN” fuse
[C]: Torque sensor connector “E31” (viewed from harness side) 5. P/S control module 10. “P/S” fuse
1. Main fuse box 6. Torque sensor 11. “IG1 SIG” fuse
2. Ignition switch 7. Individual circuit fuse box No.1
DTC detecting condition Trouble area
Circuit voltage of torque sensor 9 V power supply is less
than 7 V
(1 driving cycle detection logic)• Torque sensor 9 V power supply circuit
• Torque sensor
• P/S control module
Step Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2DTC check
Is DTC C1153 indicated, together?Go to applicable DTC
diag. flow.Go to Step 3.
3Torque sensor power supply voltage check
1) With ignition switch turned OFF, disconnect torque
sensor connector.
2) Check for voltage between “E31-3” (“GRN” wire)
terminal and body ground with ignition switch ON.
Is it approx. 9 V?Go to Step 4. Go to Step 5.
4Torque sensor power supply voltage check
1) With ignition switch turned OFF, connect torque sensor
connector.
2) Check for voltage between “E11-8” (“GRN” wire)
terminal and body ground with ignition switch ON.
Is it approx. 9 V?Substitute a known-
good P/S control
module and recheck.Replace steering gear
case.

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DTC Detecting Condition and Trouble Area
DTC TroubleshootingDTC 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 “EPS” warning light
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 “EPS” warning light
does not light up)• Vehicle speed signal circuit
•BCM
•ECM
• TCM (A/T model)
• ABS control module (M/T model)
• P/S control module
• CAN communication line circuit
Step Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2DTC check
1) 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.
3Vehicle spec check
Is vehicle equipped with A/T?Go to Step 4 Go to Step 5
4DTC check
1) Check TCM for DTC referring to “DTC Check in Section
5A”.
Is there any DTC detected?Go to applicable DTC
diag. flow.Go to Step 6.
5DTC check
1) Check ABS control module and BCM for DTC referring
to “DTC Check in Section 4E” and “DTC Check in
Section 10B”.
Is there any DTC detected?Go to applicable DTC
diag. flow.Go to Step 6.

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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.