2004 SUZUKI SWIFT Service Workshop Manual

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DTC Detecting Condition and Trouble Area
DTC TroubleshootingDTC detecting condition Trouble area
DTC C1141:
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
(1 driving cycle detection logic)
DTC C1142:
Measured motor drive current is more than 10 A as
compared with target motor drive current.
(1 driving cycle detection logic)
DTC C1143:
Measured motor drive current is more than 50 A.
(1 driving cycle detection logic)
DTC C1145:
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 cont rol duty is more than 90%
while target motor drive current is less than 8 A.
(1 driving cycle detection logic) • P/S motor circuit
• P/S motor
• P/S control module
Step
Action YesNo
1 Was “EPS System Check” performed? Go to Step 2.Go to “EPS System
Check”.
2 DTC check
Is DTC C1153 and/or DTC C1155 indicated together? Go to applicable DTC
diag. flow.
Go to Step 3.
3 Power 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.
4 Motor circuit check
1) With ignition switch tuned OFF, disconnect P/S motor
connector (“E51”).
2) Check that P/S motor circuit is as follows. • Insulation resistance of wire harness is infinity between each “P/S motor circuit” terminal and other
terminal at P/S motor connector.
• Wiring harness resistance of each “P/S motor circuit”
is less than 1 Ω.
• Insulation resistance between each “P/S motor circuit” and vehicle body ground is infinity.
• Circuit voltage between each “P/S motor circuit” and ground circuit is 0 – 1 V with ignition switch turned
ON.
Is circuit in good condition? Go to Step 5.
Repair or replace
defective circuit.
5 P/S motor check
1) Check motor and its circuit referring to “P/S Motor and Its
Circuit Inspection”.
Is motor in good condition? Substitute a known-
good P/S control
module, and recheck.
Replace the steering
gear case assembly.

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DTC C1153: P/S Control Module Power Supply Circuit Voltage LowS7RS0B6304020
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Troubleshooting
MBLK
REDE51-1
E51-2
12V
5
[A ]
12 3
4 5 67
89
11
10
12 13
141516
17 18 19 20
[B ]
1
2
LT GRN
/BLKE52-1 E49-1
GRNGRNWHTBLK
WHY
6
3
4
4
4
4
1 2
E49-2BLK
I7RS0B630011-01
[A]: Connector “E52” (viewed from harness side)
2. Ignition switch5. P/S control module
[B]: Connector “E49” (viewed from harness side) 3. Junction block assembly 6. Individual circuit fuse box No.1
1. Main fuse box 4. Fuse
DTC detecting condition Trouble area
Power supply voltage of P/S control module is less than 9
V for 5 seconds continuously
(1 driving cycle detection logic) • P/S control module power supply circuit
• Undercharged Battery
• P/S control module
Step
Action YesNo
1 Was “EPS System Check” performed? Go to Step 2.Go to “EPS System
Check”.
2 Battery 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”.
3 P/S control module power supply circuit check
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? Substitute a known-
good P/S control
module and recheck.
Repair defective circuit.

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DTC C1155: P/S Control Module FailureS7RS0B6304021
Wiring Diagram
Refer to “DTC C1153: P/S Control Module Power Supply Circuit Voltage Low”.
DTC Detecting Condition and Trouble Area
DTC Troubleshooting DTC detecting condition Trouble area
Internal memory (EEPROM) is data error.
(In this case, MIL 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) • Overcharged Battery
• P/S control module
Step
Action YesNo
1 Was “EPS System Check” performed? Go to Step 2.Go to “EPS System
Check”.
2 P/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.
3 Battery 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 CheckS7RS0B6304022
Wiring Diagram
1
[A ]
123
4 5 67
89
11
10
12 13
141516
17 18 19 20
[B ]
7
1
2
MBLK
REDE51-1
E51-2
12V
LT GRN
/BLKE52-1 E49-1
GRNGRNWHTBLK
WHY
3
3
5
6
1 2
E49-2BLK
I7RS0B630012-01
[A]: Connector “E52” (viewed from harness side)
2. Ignition switch5. “EPS” fuse
[B]: Connector “E49” (viewed from harness side) 3. Individual circuit fuse box No.1 6. “IG1 SIG” fuse
1. Main fuse box 4. Junction block assembly7. P/S control module
StepAction YesNo
1 Circuit fuse check
1) Disconnect P/S control modu le connector with ignition
switch turned OFF.
2) Check for proper connection to P/S control module connector at “E49-1”, “E49-2” and “E52-1” 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).
2 Power supply circuit check
1) Measure voltage between “E49-1” terminal of P/S
control module connector and body ground.
Is voltage 10 - 14 V? Go to Step 3.
“GRN” or “BLK” wire is
open circuit.
3 Ignition signal check
1) Turn ignition switch to ON position.
2) Measure voltage between “E52-1” 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.
4 P/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 “E49-2” 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.

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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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E52-11 PPL/WHT Data link connector——
E52-12 BRN Engine speed signal *0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.30” and “Reference
waveform No.31”
under “Inspection of
ECM and Its Circuits in Section 1A”.) Engine idling
E52-13 — —— —
E52-14 RED/BLU P/S operation signal (idle up
signal) About 12 V Ignition switch ON
0 – 1 V Engine idling and turned steering
wheel to the right or left until it stops
E52-15 — —— —
E52-16 YEL Torque sensor internal failure
signal About 5 V At the moment of Ignition switch ON
0 V Ignition switch ON
E52-17 — —— —
E52-18 WHT Torque sensor signal (Main) 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
E52-19 GRY Ground for shield wire Below 0.3 V—
E52-20 RED 5 V reference power supply
for torque sensor About 5 V• Ignition switch ON
• Check voltage between “E52-20”
and “E52-9” terminals
Terminal Wire color
Circuit Normal voltage Remarks

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Reference waveform No.1
Motor output signal 1(1), Motor output signal 2(2), with
engine idlingReference waveform No.2
Motor output signal 1(1), Motor output signal 2(2), with
engine idling
Measurement
terminal CH1: “E51-1” to vehicle body ground
CH2: “E51-2” to vehicle body ground
Oscilloscope
setting CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 20
µs/DIV
Measurement
condition • Engine is idling and steering wheel
at straight position
I6RS0B630017-01
Measurement
terminal CH1: “E51-1” to vehicle body ground
CH2: “E51-2” to vehicle body ground
Oscilloscope
setting CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 20 µ
s/DIV
Measurement
condition • Engine is idling and steering wheel
is turned to left or right at turning
speed of 90 ° /sec
[A]: Steering wheel is turned left at turning speed of 90 ° /sec
[B]: Steering wheel is turned right at turning speed of 90 ° /sec
[C]: 12 V ON
[D]: GND ON [E]: 1 duty cycle
I6RS0B630018-01