2006 SUZUKI SX4 PPL

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DTC C1121 / C1123 / C1124: Vehicle Speed Signal Circuit FailureS6RW0D6304014
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 Diagram5Torque sensor power supply circuit check
1) Check that torque sensor power supply circuit is as
follows.
• Insulation resistance of wire harness is infinity
between “Torque sensor power supply circuit” terminal
and each other terminal at torque sensor connector.
• Wiring harness resistance of “Torque sensor power
supply circuit” is less than 1 Ω.
• Insulation between “Torque sensor power supply
circuit” and vehicle body ground is infinity.
Is circuit in good condition?Replace P/S control
module.Repair or replace
defective circuit. Step Action Yes No
[A]
123
4567
8
9 11
10 12 13
141516
17 18 1920
1
2
[B]
BRN RED/
BLU LT GRN/
BLK
E11-1
E11-14
E11-12
E13-1 GRN
GRN
WHT
8
3 10
12
13
11
4 1
2
12V
E13-2BLK
12V
12V
9 5
77
E11-11
G04-15
[E]G04-22
5V
PPL
E11-4
BLU/
WHTE04-9
6
14
IG11615
C07-25
[D][C]
[F]E01-44E01-4
[F]E01-27E01-26
I6RW0D630003-01
[A]: P/S control module connector No.1 “E11” (viewed from harness side) 3. Junction block assembly 11. “IGN” fuse
[B]: P/S control module connector No.2 “E13” (viewed from harness side) 4. Main fuse 12. “P/S” fuse
[C]: M/T model 5. ECM 13. “IG1 SIG” fuse
[D]: A/T model 6. BCM 14. Vehicle speed signal
[E]: Junction block without BCM model (Taiwan model) 7. Front left/right wheel speed sensor 15. TCM
[F]: M15A engine with 4A/T equipped with slip control model (Hong Kong model) 8. P/S control module 16. Output shaft speed sensor
1. Main fuse box 9. ABS control module
2. Ignition switch 10. Individual circuit fuse box No.1

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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.

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DTC Troubleshooting
DTC C1153: P/S Control Module Power Supply CircuitS6RW0D6304017
Wiring Diagram
DTC Detecting Condition and Trouble AreaStep Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2DTC check
Is DTC C1153 and/or C1155 indicated, together?Go to applicable DTC
diag. flow.Go to Step 3.
3Power supply and ground circuit check
1) Check P/S control module power supply and ground
circuit referring to “P/S Control Module Power Supply
and Ground Circuit Check”.
Is it in good condition?Go to Step 4. Repair or replace
defective circuit.
4Motor circuit check
1) With ignition switch turned OFF, disconnect P/S control
module connector No.3 and P/S motor connector.
2) Check P/S control module connector and P/S motor
connector for proper connection.
3) If OK, check for open, short and/or high resistance in
motor circuit between P/S control module and P/S motor.
Refer to “Electrical Circuit Inspection Procedure in
Section 00”.
Are they in good condition?Go to Step 5. Repair motor circuit.
5P/S motor check
1) Check P/S motor referring to “P/S Motor and Its Circuit
Inspection”.
Is P/S motor in good condition?Substitute a known-
good P/S control
module and recheck.Replace the steering
gear case assembly and
recheck.
[A]
123
4567
8
9 11
10 12 13
141516
17 18 1920
1
2
[B]
LT GRN/
BLKE11-1E13-1 GRNGRN
WHT
5
3 6
8
9
7
4 12
12V
E13-2BLK
I6RW0C630009-01
[A]: P/S control module connector No.1 “E11” (viewed from harness side) 3. Junction block assembly 7. “IGN” fuse
[B]: P/S control module connector No.2 “E13” (viewed from harness side) 4. Main fuse 8. “P/S” fuse
1. Main fuse box 5. P/S control module 9. “IG1 SIG” fuse
2. Ignition switch 6. Individual circuit fuse box No.1
DTC detecting condition Trouble area
Power supply voltage of P/S control module is less than 9
V for 5 seconds continuously while engine speed is more
than 600 rpm.
(1 driving cycle detection logic)• P/S control module power supply circuit
• Battery
• Generator
• P/S control module

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DTC Troubleshooting
DTC C1155: P/S Control Module Internal FailureS6RW0D6304018
Wiring Diagram
Refer to “DTC C1153: P/S Control Module Power Supply Circuit”.
DTC Detecting Condition and Trouble Area
DTC TroubleshootingStep Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2Battery voltage check
1) Check circuit fuse for P/S control module.
2) If OK, measure voltage between positive (+) battery
terminal and vehicle body ground with engine running.
Is voltage 10 V or more?Go to Step 3. Check charging system
referring to “Generator
Test (Undercharged
Battery Check) in
Section 1J”.
3P/S control module power supply 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?Substitute a known-
good P/S control
module and recheck.Repair defective circuit.
DTC detecting condition Trouble area
Internal memory (EEPROM) is data error.
(In this case, “EPS” warning light does not light up)
or
Internal circuit is faulty.
or
Power supply voltage of P/S control module exceeded
17.5 V
(1 driving cycle detection logic)• Generator
• P/S control module
Step Action Yes No
1Was “EPS System Check” performed?Go to Step 2. Go to “EPS System
Check”.
2P/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 3. Repair or replace
defective circuit.
3Battery voltage check
1) Check voltage between positive (+) battery terminal and
vehicle body ground with engine speed at 3000 rpm.
Is voltage 15.5 V or less?Replace P/S control
module.Check charging system
referring to “Generator
Test (Overcharged
Battery Check) in
Section 1J”.

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P/S Control Module Power Supply and Ground Circuit CheckS6RW0D6304019
Wiring Diagram
Refer to “DTC C1153: P/S Control Module Power Supply Circuit”.
DTC Troubleshooting
Step Action Yes No
1Circuit fuse check
1) Disconnect P/S control module connector with ignition
switch turned OFF.
2) Check for proper connection to P/S control module
connector at “E13-1”, “E13-2” and “E11-1” terminals.
3) If OK, check “P/S” fuse and “IG1 SIG” fuse for blowing.
Are “P/S” fuse and “IG1 SIG” fuse in good condition?Go to Step 2. Replace fuse (s) and
check for short in
circuits connected to
fuse(s).
2Power supply circuit check
1) Measure voltage between “E13-1” terminal of P/S
control module connector and body ground.
Is voltage 10 – 14 V?Go to Step 3. “GRN” or “WHT” wire is
open circuit.
3Ignition signal check
1) Turn ignition switch to ON position.
2) Measure voltage between “E11-1” terminal of P/S control
module connector and body ground.
Is voltage 10 – 14 V?Go to Step 4. “LT GRN / BLK” or
“GRN” wire is open
circuit.
4P/S control module ground circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from P/S control module.
3) Measure resistance between “E13-2” terminals of P/S
control module connector and body ground.
Is resistance 1
Ω or less?Go to Step 5. “BLK” wire is open or
high resistance circuit.
5P/S control module ground circuit check
1) Connect connectors to P/S control module.
2) Start engine.
3) Measure voltage between “E13-2” 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 high
resistance circuit.

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Terminal Wire color Circuit Normal voltage Condition
E11-1 LT GRN/BLKIgnition switch signal for P/S
control module10 – 14 V Ignition switch ON
E11-2 — — — —
E11-3 — — — —
E11-4 PPL Vehicle speed signal*0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.7”
under “Inspection
of BCM and Its
Circuits in
Section 10B”)• Ignition switch ON
• Front left tire turned quickly with right
tire locked
E11-5 GRY “EPS” warning light0 V Ignition switch ON
0 – 14 V Engine running
E11-6 — — — —
E11-7 — — — —
E11-8 GRN9 V power supply for torque
sensorAbout 9 V• Ignition switch ON
• Voltage between “E11-8” and “E11-9”
terminals
E11-9 BLK Ground for torque sensors — —
E11-10 WHT Torque sensor signal (Sub)About 2.5 – 4.0 V• Steering wheel with left turn
• Out put voltage varies linearly
depending on steering force
About 2.5 V Steering wheel at free
About 1.0 – 2.5 V• Steering wheel with right turn
• Out put voltage varies linearly
depending on steering force
E11-11 BLUSerial communication circuit for
data link connector——
E11-12 BRN Engine speed signal*0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.24
and No.25” under
“Inspection of
ECM and Its
Circuits in
Section 1A”)Engine idling
E11-13 — — — —
E11-14 RED/BLU P/S active signal (idle up signal)About 12 V Ignition switch ON
0 – 1 VEngine idling and turned steering wheel
to the right or left until it stops
E11-15 — — — —
E11-16 — — — —
E11-17 — — — —
E11-18 YEL Torque sensor signal (Main)About 1.0 – 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 – 4.0 V• Steering wheel with right turn
• Out put voltage varies linearly
depending on steering force
E11-19 GRY Ground for shield wire — —

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NOTE
*: The voltage of this circuit may not be checked by voltmeter. If so, use oscilloscope.

Reference waveform No.1
Motor output signal 1(1), Motor output signal 2(2), with
engine idlingE11-20 REDReference sensor power supply
for torque sensorAbout 3.0 – 3.5 V• Ignition switch ON
• Check voltage between “E11-20” and
“E11-9” terminals
E12-1 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 “E12-1” and vehicle
body ground
E12-2 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 “E12-2” and vehicle
body ground
E13-1 GRNMain power supply for internal
memory and P/S motor10 – 14 V —
E13-2 BLK Ground for P/S control module Below 0.3 V — Terminal Wire color Circuit Normal voltage Condition
Measurement
terminalCH1: “E12-1” to vehicle body ground
CH1: “E12-2” to vehicle body ground
Oscilloscope
settingCH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 20 µs/DIV
Measurement
condition• Engine is idling and steering
wheel at straight position
I6RS0B630017-01