2008 SUZUKI SWIFT IDLE SPEED CONTROL

Downloaded from www.Manualslib.com manuals search engine 1A-144 Engine General Information and Diagnosis:
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors re ferring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.

DTC P1603: TCM Trouble Code DetectedS7RS0B1104061
Wiring Diagram
DTC Detecting Condition
When ECM receives a trouble code from TCM, which indicates that some problem occurred in sensor circuits and its
calculated values used for operations such as idle speed control, engine power control, and so on by TCM, ECM sets
DTC P1603. (TCM outputs the trouble code to ECM when TCM can not compute the engine control signal due to
malfunctions of sensor circuits used for gear shift control.) Step Action Yes No
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2. Go to “Engine and
Emission Control
System Check”.
2 Battery voltage supply circuit check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors
connected.
3) With engine running, measure voltage between “E23-2” terminal of ECM connector and engine ground.
Is voltage 10 – 14 V? Poor “E23-2”
connection or
intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
If wire and connections
are OK, substitute a
known-good ECM and
recheck.“RADIO” fuse blown,
“WHT” or “WHT/RED”
wire is circuit open or
short circuit.
E23
C37
34
1819
567
1011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
55
57 54 53
59
60 58 2
262728
15
30
56 4832 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
34
1819
567
1011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
55
57 54 53
59
60 58 2
262728
15
30
56 4832 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
1
RED
WHT
C37-13
C37-12
RED
WHTC34-7
C34-17
2
I6RS0C110026-01
1. ECM
2. TCM (for A/T model)

Downloaded from www.Manualslib.com manuals search engine 1A-178 Engine General Information and Diagnosis:
C37-20RED/
YEL CMP sensor signal 0 – 1 V or 4 – 5 V Ignition switch turned ON. —
*0 – 0.6 V↑↓
4 – 5 V
(“Reference
waveform No.16: ” and “Reference
waveform No.17: ”) Engine running at idle
after warmed up engine.
Sensor signal is pulse.
Pulse frequency varies
depending on engine
speed.
(6 pulses are generated
per 1 camshaft revolution.)
C37-21 PNK CKP sensor signal 0 – 1 V or 4 – 5 V Ignition switch turned ON. —
*4 – 5 V↑↓
0 – 0.6 V
(“Reference
waveform No.16: ” and “Reference
waveform No.17: ”) Engine running at idle
after warmed up engine. Sensor signal is pulse.
Pulse frequency varies
depending on engine
speed.
(30 (36 – 6) pulses are
generated per 1
crankshaft revolution.)
C37-22 — — — — —
C37-23 PNK/
BLU Electric load
current sensor
signal 3.8 – 4.2 V Ignition switch turned ON.
—
3.0 – 3.4 V
Ignition switch turned ON
and headlight switch
turned ON (HI beam).
2.3 – 2.7 V Ignition switch turned ON,
headlight switch turned
ON (HI beam) and blower
selector at HI position.
C37-24 LT GRN ECT sensor signal 3.3 – 3.8 V
Ignition switch turned ON,
ECT at 0
°C, 32 °F.
—
1.38 – 1.72 V Ignition switch turned ON,
ECT at 50
°C, 122 °F.
0.40 – 0.53 V Ignition switch turned ON,
ECT at 100
°C, 212 °F.
C37-25 BLK/
YEL IAT sensor signal 3.18 – 3.67 V
Ignition switch turned ON,
IAT at 0
°C, 32 °F.
—
1.32 – 1.65 V Ignition switch turned ON,
IAT at 40
°C, 104 °F.
0.46 – 0.60 V Ignition switch turned ON,
IAT at 80
°C, 176 °F.
C37-26 GRN/
BLK MAF sensor signal 0.5 – 1.5 V
Ignition switch turned ON
with engine at stop.
—
1.5 – 2.0 V
(“Reference
waveform No.18: ”) Wh

en engine running at
specified idle speed after
warmed up.
C37-27 GRY Ground for MAF
sensor Below 0.3 V Ignition switch turned ON.
—
C37-28 BLU/
YEL Generator control
signal output *0 – 0.6 V
↑↓
5 – 8 V
(“Reference
waveform No.19: ”) Engine running at idle
speed, headlight switch
turned ON.
Output signal is active low
duty pulse. Duty ratio
varies depending on
vehicle condition.
C37-29 BLU/
BLK EVAP canister
purge valve output 10 – 14 V
Ignition switch turned ON
with engine at stop. —
*0 – 0.6 V ↑↓
10 – 14 V
(“Reference
waveform No.20: ”) Set EVAP canister purge
valve at 52% by using
“Misc Test” of scan tool.
Output signal is active low
duty pulse. Duty ratio
varies depending on
vehicle condition.
C37-30 BLK Ground for ECM Below 0.3 V Ignition switch turned ON. —
C37-31 — —— — —
Terminal
No. Wire
color Circuit Normal voltage
ConditionRemarks

Downloaded from www.Manualslib.com manuals search engine 1A-180 Engine General Information and Diagnosis:
C37-50 —Ground of ECM for
shield wire Below 0.3 V Ignition switch turned ON. —
C37-51 — Ground of ECM for
shield wire Below 0.3 V Ignition switch turned ON. —
C37-52 — Ground of ECM for
shield wire Below 0.3 V Ignition switch turned ON. —
C37-53 RED/
BLK MAP sensor signal Approx. 4 V
(“Reference
waveform No.23: ”) Ignition switch turned ON
with barometric pressure
at 100 kPa, 760 mmHg.
—
0.4 – 2.0 V
(“Reference
waveform No.24: ”) While engine running at
specified idle speed after
warmed up with
barometric pressure at
100 kPa, 760 mmHg.
C37-54 GRN TP sensor (main)
signal 0.75 – 1.08 V
Ignition switch turned ON
and accelerator pedal at
idle position after warmed
up engine.
—
3.67 – 4.24 V Ignition switch turned ON
and accelerator pedal at
full depressed position
after warmed up engine.
C37-55 ORN Ground for sensors Below 0.3 V Ignition switch turned ON. —
C37-56 RED Knock sensor
signal 2 – 3 V
(“Reference
waveform No.25: ” and “Reference
waveform No.26: ”) Ignition switch turned ON.
—
Engine running at 4000 r/
min. after warmed up.
C37-57 YEL Ground for sensors Below 0.3 V Ignition switch turned ON. —
C37-58 BLK/
ORN Ground for ECM Below 0.3 V Ignition switch turned ON.
—
C37-59 YEL/
GRN Oil control valve
ground
Below 1.3 V Ignition switch turned ON.
—
C37-60 YEL/
RED Oil control valve
output *0 – 0.6 V
↑↓
10 – 14 V
(“Reference
waveform No.27: ” and “Reference
waveform No.28: ”) At the moment of ignition
switch turned ON.
Output signal is active
high pulse. Duty ratio
varies depending on
vehicle condition.
Terminal
No. Wire
color Circuit Normal voltage
ConditionRemarks
Terminal
No. Wire
color Circuit Normal voltage Condition Remarks
E23-1 BLK/
RED Main power supply 10 – 14 V Ignition switch turned ON. —
E23-2 WHT/
RED Power source for
ECM internal
memory
10 – 14 V Ignition switch turned ON. —
E23-3 RED CAN (high)
communication line
(active high signal)
for ABS control
module, BCM,
combination meter *2.5 – 4.5 V
(“Reference
waveform No.29: ”) Ignition switch turned ON
with engine at stop. CAN communication line
signal is pulse. Pulse
signal displayed with a
regular frequency with
varies depending on
engine condition.

Downloaded from www.Manualslib.com manuals search engine 1A-182 Engine General Information and Diagnosis:
E23-25 PPLVehicle speed
signal output for P/
S control module *0 – 1 V
↑↓
10 – 14 V
(“Reference
waveform No.32: ”) Vehicle running. Sensor signal is pulse.
Pulse frequency varies
depending on vehicle
speed.
(21 pulses are generated
per sec. at 30 km/h, 19
mph.) (2561 pulses/km)
E23-26 RED/
BLU EPS signal 10 – 14 V Ignition switch turned ON.
—
0 – 1 V With engine running at idle
speed, and steering wheel
turned to the right or left as
far as it stops.
E23-27 — — — — —
E23-28 YEL/
BLK Serial
communication line
for immobilizer coil
antenna
10 – 14 V Ignition switch turned ON. —
E23-29 BLK/
WHT Ignition switch
signal 0 – 1 V Ignition switch turned OFF.
—
10 – 14 V Ignition switch turned ON.
E23-30 WHT Starting motor
control relay output 0 – 1 V Ignition switch turned ON.
—
0 – 1 V Ignition switch is turned to
ST (engine cranking)
position.
E23-31 BLK Ground for ECM Below 0.3 V Ignition switch turned ON. —
E23-32 RED/
YEL Power supply of
throttle actuator
drive circuit
10 – 14 V Ignition switch turned ON. —
E23-33 — — — — —
E23-34 RED Output for 5 V
power source of
APP sensor (sub) 4.5 – 5.5 V Ignition switch turned ON. —
E23-35 BRN Output for 5 V
power source of
APP sensor (main) 4.5 – 5.5 V Ignition switch turned ON. —
E23-36 YEL APP sensor (sub)
signal 1.55 – 1.65 V
Ignition switch turned ON
and accelerator pedal at
idle position after warmed
up engine.
—
4.18 – 5.12 V Ignition switch turned ON
and accelerator pedal at
full depressed position
after warmed up engine.
E23-37 YEL APP sensor (main)
signal 0.75 – 0.85 V
Ignition switch turned ON
and accelerator pedal at
idle position after warmed
up engine.
—
3.46 – 4.24 V Ignition switch turned ON
and accelerator pedal at
full depressed position
after warmed up engine.
E23-38 — — — — —
E23-39 — — — — —
E23-40 — — — — —
E23-41 — — — — —
E23-42 — — — — —
E23-43 — — — — —
E23-44 — — — — —
Terminal
No. Wire
color Circuit Normal voltage Condition Remarks

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-189
Reference waveform No.18
MAF sensor signal (1) with engine racing
Reference waveform No.19
Generator control signal (1) at engine idlingReference waveform No.20
EVAP canister purge valve signal
Measurement
terminal CH1: “C37-26” to “C37-27”
CH2: “C37-54” to “C37-55”
Oscilloscope
setting CH1: 1 V/DIV, CH2: 1 V/DIV
TIME: 200 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine racing
2. TP sensor signal
3. Racing
4. Idle
Measurement
terminal CH1: “C37-28” to “C37-58”
Oscilloscope
setting CH1: 5 V/DIV
TIME: 10 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine at specified idle speed
• For a few sec. from headlight switch turned ON
I4RS0B110066-01
I7RS0B110015-01
Measurement
terminal CH1: “C37-29” to “C37-58”
Oscilloscope
setting CH1: 10 V/DIV
TIME: 40 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• EVAP canister purge valve setting at 52% by using “Misc Test” of
scan tool
1. ON signal
2. OFF signal
3. One duty cycle
4. 10 – 14 V
I4RS0B110067-01

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-191
Reference waveform No.24
MAP sensor signal (1) with engine racing
Reference waveform No.25
Knock sensor signal at engine speed 4000 r/min.Reference waveform No.26
Knock sensor signal at engine speed 4000 r/min.
Reference waveform No.27
Oil control valve signal with engine idling
Measurement
terminal
CH1: “C37-53” to “C37-55”
CH2: “C37-54” to “C37-55”
Oscilloscope
setting CH1: 2 V/DIV, CH2: 2 V/DIV
TIME: 200 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine racing
2. TP sensor signal
3. Racing
4. Idle
Measurement
terminal CH1: “C37-56” to “C37-58”
Oscilloscope
setting CH1: 1 V/DIV
TIME: 10 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine running at 4000 r/min.
I4RS0B110071-01
I4RS0B110072-01
Measurement
terminal CH1: “C37-56” to “C37-58”
Oscilloscope
setting CH1: 1 V/DIV
TIME: 200
µs/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine running at 4000 r/min.
Measurement
terminal CH1: “C37-60” to “C37-59”
Oscilloscope
setting CH1: 5 V/DIV
TIME: 2 ms/DIV
Measurement
condition At the moment of the ignition switch
turned on
1. ON signal
2. OFF signal
3. Only duty cycle
I4RS0B110073-01
I4RS0B110074-01

Downloaded from www.Manualslib.com manuals search engine 1A-192 Engine General Information and Diagnosis:
Reference waveform No.28
Oil control valve signal with engine racing
Reference waveform No.29
CAN communication line signal from each control
module with ignition switch turned ONReference waveform No.30
Ignition pulse (engine revolution) signal (2) with engine
idling
Reference waveform No.31
Ignition pulse (engine revolution) signal (2) with engine
idling
Measurement
terminal
CH1: “C37-60” to “C37-59”
Oscilloscope
setting CH1: 5 V/DIV
TIME: 400
µs/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Vehicle driving at 20 km/h (12 mph) and depress accelerator
pedal fully
1. Accelerator pedal depressed fully
2. Accelerator pedal depressed partially
3. Oil control valve signal
4. ON signal
5. OFF signal
Measurement
terminal CH1: “E23-3” to “C37-58”
CH2: “E23-18” to “C37-58”
Oscilloscope
setting CH1: 1 V/DIV, CH2: 1 V/DIV
TIME: 40
µs/DIV
Measurement
condition Ignition switch turned ON
(Signal pattern is depending on
engine condition)
1. CAN communication line signal (High)
2. CAN communication line signal (Low)
I4RS0B110075-01
I4RS0B110076-01
Measurement
terminal
CH1: “C37-20” to “C37-58”
CH2: “E23-4” to “C37-58”
Oscilloscope
setting CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 40 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine at specified idle speed
1. Cylinder reference signal (CMP reference signal)
3. 720 ° crank angle
Measurement
terminal CH1: “C37-20” to “C37-58”
CH2: “E23-4” to “C37-58”
Oscilloscope
setting CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 10 ms/DIV
Measurement
condition • After warmed up to normal
operating temperature
• Engine at specified idle speed
1. Cylinder reference signal (CMP reference signal)
3. 360 ° crank angle
4. 2 to 4 msec.
5. 10 – 14 V
I6RS0C110036-01
I6RS0C110037-01

Downloaded from www.Manualslib.com manuals search engine 1A-216 Engine General Information and Diagnosis:
Repair Instructions
Idle Speed and IAC Throttle Valve Opening
Inspection
S7RS0B1106001
Before idle speed check, make sure of the following.
• Lead wires and hoses of electronic fuel injection and engine and emission control systems are connected
securely.
• Valve lash is checked according to maintenance schedule.
• Ignition timing is within specification.
• All accessories (wipers, heater, lights, A/C, etc.) are out of service.
• Air cleaner has been properly installed and is in good condition.
• No abnormal air drawn in from air intake system.
After all items are confirmed, check idle speed and IAC
duty as follows.
NOTE
Before starting engine, place transmission
gear shift lever in “Neutral” (shift selector
lever to “P” range for A/T vehicle), and set
parking brake and block drive wheels.

1) Connect SUZUKI scan tool to DLC (1) with ignition
switch turned OFF.
Special tool
(A): SUZUKI scan tool 2) Warm up engine to normal operating temperature.
3) Check engine idle speed and “IAC throttle opening”
by using “Data List” mode on scan tool to check “IAC
throttle opening”.
4) If check result is out of sp ecification, inspect electric
throttle body assembly referring to “Electric Throttle
Body Assembly On-Vehicle Inspection in Section
1C”.
Engine idle speed
A/C OFF: 700 ± 50 rpm (IAC duty: 5 – 55%)
A/C ON: 850 ± 50 rpm
5) Check that specified engine idle speed is obtained with A/C turned ON if vehi cle is equipped with A/C.
If not, check A/C system.
(A)
1
I4RS0B110093-01