C37 SUZUKI SWIFT 2007 2.G Service Service Manual
Page 154 of 1496
Downloaded from www.Manualslib.com manuals search engine 1A-104 Engine General Information and Diagnosis: 
4Wire harness check
1) Disconnect connectors from ECM with ignition switch 
turned OFF.
2) Check for proper connection of ECM connector at “C37- 43” terminal.
3) Measure voltage between “C37-43” terminal of ECM  connector and engine ground with ignition switch turned 
ON.
Is voltage 0 V? Substitute a known-
good ECM and recheck.
“RED” wire is shorted to 
power circuit.
5 Wire harness check
1) Measure voltage between “WHT” wire terminal of 
electric throttle body connector and engine ground with 
ignition switch turned ON.
Is voltage 4 – 6 V? Go to Step 9.
Go to Step 6.
6 Wire harness check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors 
connected.
3) Check for proper connection of ECM connector at “C37- 43” and “C37-40” terminals.
4) If OK, measure voltage between “C37-40” terminal of  ECM connector and engine ground with ignition switch 
turned ON.
Is voltage 4 – 6 V? “WHT” wire is open or 
high resistance circuit.
Go to Step 7.
7 Wire harness check
1) Disconnect connectors from ECM with ignition switch 
turned OFF.
2) Measure resistance between “WHT” and “RED” wire  terminals of electric thrott le body assembly connector.
Is resistance infinity? Go to Step 8.
“WHT” wire is shorted to 
“RED” wire.
8 Wire harness check
1) Turn ON ignition switch.
2) Measure voltage between “C37-40” terminal of ECM 
connector and engine ground.
Is voltage 0 V? Substitute a known-
good ECM and recheck.
“WHT” wire is shorted to 
power circuit.
9 Ground circuit check
1) Turn OFF ignition switch.
2) Measure resistance between “BLK” wire terminal of 
electric throttle body connector and engine ground.
Is resistance below 5 
Ω? Go to Step 11. Go to Step 10.
10 Ground circuit check
1) Remove ECM from its br acket with ECM connectors 
connected.
2) Check for proper connection of ECM connector at “C37- 42” terminal.
3) Measure resistance between “C37-42” terminal of ECM  connector and engine ground with ignition switch turned 
OFF.
Is resistance below 5 
Ω? “BLK” wire is open or 
high resistance circuit.
Faulty ECM ground 
circuit. If circuit is OK, 
substitute a known-
good ECM and recheck.
Step Action Yes No  
Page 157 of 1496
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DTC P0327 / P0328: Knock Sensor 1 Circuit Low / HighS7RS0B1104040
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure1) Connect scan tool to DLC with  ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC by using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC by using scan tool. 11
Engine mechanical system check
1) Check engine mechanical parts or system which can 
cause engine rough idle or poor performance.
• Engine compression (Refer to “Compression Check in Section 1D”.)
• Valve lash (Refer to “Valve Lash (Clearance)  Inspection in Section 1D”.)
• Valve timing (Refer to “Timing Chain and Chain  Tensioner Removal and Installation in Section 1D”.)
Are they in good condition? Check wire harness and 
connection of ECM 
ground, ignition system 
and fuel injector for 
intermittent open and 
short.
Repair or replace 
defective part.
Step
Action YesNo
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 2
REDC37-56
5 V
I4RS0A110031-01
1. Knock sensor
2. ECM
DTC detecting condition Trouble area
DTC P0327:
Voltage of knock sensor is less than 1.23 V for 0.5 seconds 
continuously.
(1 driving cycle detection logic)
DTC P0328:
Voltage of knock sensor is 3.91 V or more for 0.5 seconds 
continuously
(1 driving cycle detection logic) • Knock sensor circuit (open or short)
• Knock sensor
•ECM  
Page 158 of 1496
Downloaded from www.Manualslib.com manuals search engine 1A-108 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.
 
Step Action YesNo
1 Was “Engine and Emission Control System Check” 
performed? Go to Step 2.
Go to “Engine and 
Emission Control 
System Check”.
2 Knock sensor circuit check
1) Remove ECM from its br acket with ECM connectors 
connected.
2) Measure voltage between “C37-56” terminal of ECM  connector and vehicle body ground with engine running.
Is voltage within 1.23 – 3.91 V? Intermittent trouble. 
Check for intermittent 
referring to “Intermittent 
and Poor Connection 
Inspection in Section 
00”. If OK, substitute a 
known-good ECM and 
recheck.Go to Step 3.
3 Knock sensor circuit for open check
1) Disconnect connector from knock sensor with ignition 
switch turned OFF.
2) Turn ON ignition switch, measure voltage between  “RED” wire of knock sensor connector and engine 
ground.
Is voltage 4 – 6 V? Go to Step 6.
Go to Step 4.
4 Knock sensor circuit for open check
1) Turn ON ignition switch, measure voltage between “C37-
56” terminal of ECM connector and engine ground
Is voltage 4 – 6 V? “RED” wire is open 
circuit.
Go to Step 5.
5 Knock sensor circuit for short check
1) Disconnect connectors from ECM with ignition switch 
turned OFF.
2) Measure resistance between “C37-56” terminal of ECM  connector and vehicle body ground.
Is resistance infinity? Go to Step 6.
“RED” wire is shorted to 
ground circuit.
If wire is OK, substitute 
a known-good ECM and 
recheck.
6 Knock sensor circuit for short check
1) Disconnect connectors from ECM with ignition switch 
turned OFF.
2) Turn ON ignition switch, measure voltage between “C37- 56” terminal of ECM connector and vehicle body ground.
Is voltage 0 V? Go to Step 7.
“RED” wire is shorted to 
other circuit.
I2RH01110089-01  
Page 159 of 1496
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DTC P0335: Crankshaft Position (CKP) Sensor “A” CircuitS7RS0B1104041
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Crank engine for 3 – 5 sec.
4) Check DTC. 7
Knock sensor circuit for high resistance check
1) Turn OFF ignition switch, measure resistance between 
“C37-56” terminal of ECM connector and “RED” wire 
terminal of knock sensor harness connector.
Is resistance below 5 
Ω? Faulty knock sensor. “RED” wire is high 
resistance circuit.
Step
Action YesNo
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
12V
5V
BLK/RED
BLK/RED
BLK/YELBLK/YEL
BLK/YEL
BRN/WHT
5
9 4
13
3
C37-30C37-15
C37-58
E23-31
BLK/ORN
BLKBLKBLK
10
BLK/RED
BLK/RED
E23-16
E23-60
E23-1
BLK/ORN
1
15
C37-21 5V
7RED/WHTGRN/WHT
GRN
RED
BLK/WHT
YEL/GRN
YEL/GRN
WHT
[A]: YEL
[B]: YEL/GRN
68
12
11
14
PNK
2
WHT
WHT/BLU
C37-48
E23-30
E23-29
I6RS0C110016-01
[A]: For A/T model 5. Ignition switch 11. “ST MOT” fuse
[B]: For M/T model 6. Starting motor 12. “ST SIG” fuse
1. CKP sensor 7. Starting motor control relay 13. “IG COIL” fuse
2. Sensor plate on crankshaft 8. Transmission range switch (for A/T model) 14. “IG ACC” fuse
3. ECM 9. Main fuse box 15. To CMP sensor
4. Main relay 10. “FI” fuse
DTC detecting condition Trouble area
No CKP sensor signal for 2 se c. even if starting motor 
signal is inputted at engine cranking.
(1 driving cycle detection logic) • CKP sensor circuit open or short
• Sensor plate teeth damaged
• CKP sensor malfunction, foreign material being attached 
or improper installation
•ECM
• Engine start signal circuit malfunction  
Page 161 of 1496
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DTC P0340: Camshaft Position (CMP) Sensor “A” CircuitS7RS0B1104042
Wiring Diagram6
Was terminal “B+” voltage in Step 3 within specification? Go to Step 7. “BLK/RED” wire is open 
circuit. If wire and 
connection are OK, 
substitute a known-
good ECM and recheck.
7 Engine start signal check
1) Check starting motor circuit for opening and short 
referring to Step 2 of “DTC P0616: Starter Relay Circuit 
Low” and Step 3 and 4 of “DTC P0617: Starter Relay 
Circuit High”.
Is check result satisfactory? Go to Step 8. Repair or replace.
8 CKP sensor check
1) Check CKP sensor and sensor plate tooth referring to 
“Camshaft Position (CMP) Sensor Inspection in Section 
1C”.
Is check result satisfactory? Substitute a known-
good ECM and recheck.
Replace CKP sensor 
and/or sensor plate.
Step Action Yes No
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
12V
5V
BLK/RED
BLK/RED
BLK/YELBLK/YEL
BLK/YEL
BRN/WHT
5
6 4
8
3
C37-30C37-15
C37-58
E23-31
BLK/ORN
BLKBLKBLK
BLK/RED
BLK/RED
E23-16
E23-60
E23-1
BLK/ORN
1
10
C37-20 5V
GRNBLK/WHT
9
7
RED/YEL
2
WHTE23-29
I6RS0C110017-01
1. CMP sensor 4. Main relay 7. “FI” fuse 10. To CKP sensor
2. Signal rotor 5. Ignition switch 8. “IG COIL” fuse
3. ECM 6. Main fuse box 9. “IG ACC” fuse  
Page 164 of 1496
Downloaded from www.Manualslib.com manuals search engine 1A-114 Engine General Information and Diagnosis: 
DTC P0350: Ignition Coil Primary / Secondary CircuitS7RS0B1104043
Wiring Diagram
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure1) With ignition switch turned OFF, connect scan tool to DLC.
2) Turn ON ignition switch and clear DTC.
3) Start engine and increase engine speed to 1500 rpm for 5 seconds.
4) Check DTC.
BLK/WHT
GRN
WHT
BLK/ORN
BLKBLK
BLK/WHT
4 3
1 7
GRN/YEL
GRN/WHT
C37-6
C37-5
C37-58
C37-15C37-30
BLKE23-31
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 48 32 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
8BLK/WHT
E23-29  
BLK
5 6BLK
2
I6RS0C110018-03
1. Ignition coil assembly for No.1 and No.4 spark plugs
4. No.1 spark plug7. No.4 spark plug
2. Ignition coil assembly for No.2 and No.3 spark plugs 5. No.2 spark plug8. “IG COIL” fuse
3. ECM 6. No.3 spark plug
DTC detecting conditionTrouble area
Ignition signal is not inputted to monitor circuit 5 times or 
more continuously. • Ignition coil assembly and/or its circuit
•ECM  
Page 169 of 1496
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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.
 
Step Action YesNo
1 Was “Engine and Emission Control System Check” 
performed? Go to Step 2.
Go to “Engine and 
Emission Control 
System Description”.
2 EGR valve power supply circuit check
1) Remove air intake pipe.
2) With ignition switch turned  OFF, disconnect EGR valve 
connector.
3) With ignition switch turned ON, measure voltage  between “BLK/RED” wire terminal of EGR valve 
connector and vehicle body ground.
Is check voltage 10 – 14 V? Go to Step 3.
“BLK/RED” wire is open 
circuit.
3 Wire circuit check
1) Disconnect connectors from ECM with ignition switch 
turned OFF.
2) Turn ON ignition switch.
3) Measure voltage between engine ground and each  “GRN/RED”, “GRN/ORN”, “W HT/RED”, “BRN/YEL” wire 
terminals of EGR valve connector.
Is each voltage 0 V? Go to Step 4.
Faulty wire(s) are 
shorted to other circuit.
If wires are OK, 
substitute a known-
good ECM and recheck.
4 Wire circuit check
1) With ignition switch turned OFF, measure resistance 
between engine ground and each “GRN/RED”, “GRN/
ORN”, “WHT/RED”, “BRN/YEL”  wire terminals of EGR 
valve connector.
Is resistance infinity? Go to Step 5.
Faulty wire(s) are 
shorted to ground 
circuit.
If wires are OK, 
substitute a known-
good ECM and recheck.
5 Short circuit check for EGR valve control circuit
1) With ignition turned OFF, measure resistance between 
each EGR valve control circ uit wire (“GRN/RED”, “GRN/
ORN”, “WHT/RED” and “BRN/ YEL” wire) and each EGR 
valve control circuit wire.
Is each resistance infinity? Go to Step 6.
Faulty wire(s) are short 
circuit.
6 EGR valve stepper motor coil circuit check
1) With ignition switch turned OFF, connect EGR valve 
connector.
2) Measure resistance between “E23-1/16” and each “C37- 4”, “C37-3”, “C37-19”, “C37-18” terminals of ECM 
connector.
Is each resistance 20 – 31 
Ω at 20 °C, 68 °F? Faulty ECM. Substitute 
a known-good ECM and 
recheck.
Go to Step 7.
7 EGR valve check
1) Check EGR valve resistance  referring to “EGR Valve 
Inspection in Section 1B”.
Is resistance within specified value? Faulty wire(s) are open 
or high resistance 
circuit. If wires are OK, 
substitute a known-
good ECM and recheck.Faulty EGR valve.  
Page 170 of 1496
Downloaded from www.Manualslib.com manuals search engine 1A-120 Engine General Information and Diagnosis: 
DTC P0420: Catalyst System Efficiency below ThresholdS7RS0B1104046
System and Wiring Diagram
Circuit Description
ECM monitors oxygen concentration in the exhaust gas which has passed the warm up three way catalytic converter 
by HO2S-2. When the catalyst is functioning properly,  the variation cycle of HO2S-2 output voltage (oxygen 
concentration) is slower than that of  HO2S-1 output voltage because of the amount of oxygen in the exhaust gas 
which has been stored in warm up three way catalytic converter.
Reference
Oscilloscope waveforms
C37-11
C37-10
C37-57
WHT
BRN
1
3 2
4
5 VYELYEL
BLUWHTBLUWHT 5
I4RS0A110037-01
1. HO2S-1
3. Warm up three way catalytic converter 5. ECM
2. HO2S-2 4. Three way catalytic converter
I2RH01110102-01  
Page 172 of 1496
Downloaded from www.Manualslib.com manuals search engine 1A-122 Engine General Information and Diagnosis: 
DTC P0443: Evaporative Emission System Purge Control Valve CircuitS7RS0B1104047
Wiring Diagram 
DTC Detecting Condition and Trouble Area3
HO2S-2 output voltage check
1) Check output voltage of HO2S-2 referring to “DTC 
P0137 / P0138: O2 Sensor (HO2S) Circuit Low Voltage / 
High Voltage (Sensor-2)” and “DTC P0137 / P0138: O2 
Sensor (HO2S) Circuit Low Voltage / High Voltage 
(Sensor-2)”.
Is check result satisfactory? Replace exhaust 
manifold (built in warm 
up three way catalytic 
converter) and exhaust 
center pipe (built in 
three way catalytic 
converter).
Check “BRN” and / or 
“YEL” wires for open 
and short, and 
connections for poor 
connection.
If wires and connections 
are OK, replace HO2S-
2.
Step Action Yes No
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 33 1
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 48 32 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
BLK/WHT
BLK/RED
BLK/RED
WHTBLK/YELBLK/YEL
BLK/YEL
GRN
BRN/WHT
12V 5V
5
4 2
3 6E23-29  
E23-1  
E23-60  
C37-58  
C37-15  C37-30  
BLK/ORN
BLKBLKE23-31  BLK
7
8
BLK/REDBLK/REDE23-16  
1
C37-29  BLU/BLK
I6RS0C110020-02
1. EVAP canister purge valve
4. Main fuse box7. “FI” fuse
2. Main relay 5. Ignition switch8. “IG ACC” fuse
3. “IG COIL” fuse 6. ECM
DTC detecting conditionTrouble area
Monitor signal of EVAP canister purge valve is different from 
command signal. (Circuit open or short)
(2 driving cycle detection logic) • EVAP canister purge valve
• EVAP canister purge valve circuit
•ECM  
Page 173 of 1496
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DTC Confirmation Procedure
WARNING! 
• When performing a road test, select a place where there is no traffic or possibility of a traffic accident and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out by 2 persons, a driver and a tester, on a level road.
 
1) With ignition switch OFF, connect scan tool to DLC.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up normal operating temperature.
4) Drive vehicle at more than 40 km/h, 25 mph for 5 min. or more.
5) Check DTC and pending DTC.
DTC Troubleshooting
WARNING! 
In order to reduce risk of fire and personal injury, this work must be performed in a well ventilated area 
and away from any open flames such as gas water heater.
 
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.
 
Step Action YesNo
1 Was “Engine and Emission Control System Check” 
performed? Go to Step 2.
Go to “Engine and 
Emission Control 
System Check”.
2 EVAP canister purge power supply circuit check
1) Turn OFF ignition switch and disconnect connector from 
EVAP canister purge valve.
2) Measure voltage between engine ground and “BLK/ RED” wire terminal of EVAP canister purge valve 
connector with ignition switch turned ON.
Is it voltage 10 – 14 V? Go to Step 3.
“BLK/RED” wire is open 
circuit.
3 Wire circuit check
1) Disconnect connectors from ECM with ignition switch 
turned OFF.
2) Measure resistance between “C37-29” terminal of ECM  connector and vehicle body ground.
Is resistance infinity? Go to Step 4.
“BLU/BLK” wire is 
shorted to ground 
circuit.
4 Wire circuit check
1) Measure voltage between “C37-29” terminal of ECM 
connector and vehicle body  ground with ignition switch 
turned ON.
Is voltage 0 V? Go to Step 5.
“BLU/BLK” wire is 
shorted to other circuit.