IAT SUZUKI SWIFT 2008 2.G Service Service Manual

Downloaded from www.Manualslib.com manuals search engine 1A-70 Engine General Information and Diagnosis:
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure
NOTE
Check to make sure that following conditions are satisfied when using this “DTC Confirmation
Procedure”.
• Intake air temperature at engine start: –10 °C (14 ° F) to 80 °C (176 °F)
• Intake air temperature: –10 °C (14 °F) to 70 °C (158 °F)
• Engine coolant temperature at engine start: less than 30 °C (86 °F)
• Engine coolant temperature: 70 °C (158 °F) to 150 °C (302 °F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch, clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature. (ECT approx. 90 – 95 °C, 194 – 203 °F)
4) Run engine at idle speed for 10 min. or more.
5) Check DTC and pending DTC.
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 detecting condition Trouble area
Difference of maximum IAT minus minimum IAT is less than 0.3 °C
(32.5 °F) while ECT is over 70 °C (158 °F) after 10 min from cold
engine start (ECT is lower than 30 °C (86 °F) at engine start).
(2 driving cycle detection logic) • High resistance circuit
• MAF and IAT sensor
•ECM
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 IAT sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ignition switch to ON position.
3) Check intake air temp. displayed on scan tool.
Is –40
°C (–40 °F) or 119 °C (246 °F) indicated? Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-71
3Wire harness check
1) Disconnect MAF and IAT sensor connector (1) with
ignition switch turned OFF.
2) Check for proper connection to MAF and IAT sensor connector (1) at “BLK/YEL” wire terminal.
3) If OK, then with ignition switch turned ON, measure voltage between “BLK/YEL” wire terminal of MAF and
IAT sensor connector and vehicle body ground.
Is measured voltage applied to “BLK/YEL” wire terminal
about 4 – 6 V? Go to Step 8. Go to Step 4.
4 ECM voltage 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- 25” terminal.
4) If OK, then turn ON igniti on switch, measure voltage
between “C37-25” terminal of ECM connector and
vehicle body ground.
Is voltage about 4 – 6 V at terminal? “BLK/YEL” wire is open
circuit.
If wire and connection
are OK, go to Step 5.
Go to Step 5.
5 Wire circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “BLK/YEL” wire terminal of MAF and IAT sensor connector and vehicle body
ground.
Is resistance infinity? Go to Step 6. “BLK/YEL” wire is
shorted to ground or
other circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
6 Wire circuit check
1) Turn ignition switch to ON position.
2) Measure voltage between “BLK/YEL” wire terminal of
MAF and IAT sensor connector and vehicle body
ground.
Is voltage about 0 V? Go to Step 7. “BLK/YEL” wire shorted
to other circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
7 Wire circuit check
1) Measure resistance between “C37-25” terminal of ECM
connector and “BLK/YEL” wire terminal of MAF and IAT
sensor connector with ignition switch turned OFF.
Is resistance below 3
Ω? Go to Step 8.
“BLK/YEL” wire is high
resistance circuit.
Step
Action YesNo
I4RS0B110020-01

Downloaded from www.Manualslib.com manuals search engine 1A-72 Engine General Information and Diagnosis:
DTC P0112: Intake Air Temperature Sensor 1 Circuit LowS7RS0B1104024
Wiring Diagram
Refer to “DTC P0111: Intake Air Temperature Sensor 1 Circuit Range / Performance”.
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) Start engine and run it for 10 sec.
4) Check DTC.
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.

8 Ground circuit check
1) Connect connectors to ECM.
2) Check for proper connection of MAF and IAT sensor
connector at “GRY/BLU” wire terminal.
3) Measure resistance between “GRY/BLU” wire terminal of MAF and IAT sensor connector and vehicle body
ground with ignition switch turned OFF.
Is resistance below 5
Ω? Go to Step 10. Go to Step 9.
9 Ground circuit check
1) Remove ECM from its br acket with ECM connectors
connected.
2) Measure resistance between “C37-55” terminal of ECM connector and vehicle body ground.
Is resistance below 3
Ω? “GRY/BLU” wire and/or
“ORN” wire is open or
high resistance circuit.
Poor “C37-55”
connection.
Faulty ECM ground
circuit.
If circuit is OK,
substitute a known-
good ECM and recheck.
10 IAT sensor check
1) Check IAT sensor according to “MAF and IAT Sensor
Inspection in Section 1C”.
Is it in good condition? Substitute a known-
good ECM and recheck.
Replace MAF and IAT
sensor.
Step Action Yes No
DTC detecting condition
Trouble area
IAT sensor output voltage is less than 0.15 V for 0.5 seconds
continuously.
(High intake air temperature (low voltage/low resistance))
(1 driving cycle detection logic) • IAT sensor circuit
• IAT sensor
•ECM

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-73
StepAction YesNo
1 Was “Engine and Emission Control System Check”
performed? Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2 IAT sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ON ignition switch.
3) Check intake air temp. displayed on scan tool.
Is 119
°C (246 °F) indicated? Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
3 ECM voltage check
1) Disconnect connector from MAF and IAT sensor with
ignition switch turned OFF.
2) Check for proper connection to MAF and IAT sensor at “BLK/YEL” and “GRY/BLU” wire terminals.
3) If OK, then turn ON igniti on switch, measure voltage
between “BLK/YEL” wire terminal of MAF and IAT
sensor connector (1) and vehicle body ground.
Is voltage about 4 – 6 V? Go to Step 6. Go to Step 4.
4 IAT short circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “BLK/YEL” wire terminal of MAF and IAT sensor connector and vehicle body
ground.
Is resistance infinity? Go to Step 5. “BLK/YEL” wire is
shorted to ground
circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
5 IAT short circuit check
1) Turn ON ignition switch.
2) Measure voltage between “BLK/YEL” wire terminal of
MAF and IAT sensor connector and vehicle body
ground.
Is voltage about 0 V? Go to Step 6. “BLK/YEL” wire is
shorted to other circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
6 IAT sensor for performance check
1) Check IAT sensor according to “MAF and IAT Sensor
Inspection in Section 1C”.
Is it in good condition? Substitute a known-
good ECM and recheck.
Replace MAF and IAT
sensor.
I4RS0B110020-01

Downloaded from www.Manualslib.com manuals search engine 1A-74 Engine General Information and Diagnosis:
DTC P0113: Intake Air Temperature 1 Sensor Circuit HighS7RS0B1104025
Wiring Diagram
Refer to “DTC P0111: Intake Air Temperature Sensor 1 Circuit Range / Performance”.
DTC Detecting Condition and Trouble Area
NOTE
When DTC P0108 and P0118 are indicated together, it is possible that “ORN” wire circuit is open.

DTC Confirmation Procedure
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC.
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 detecting condition Trouble area
IAT sensor output voltage is hi gher than 4.85 V for 0.5 seconds
continuously.
(Low intake air temperature (high voltage/high resistance))
(1 driving cycle detection logic) • IAT sensor circuit
• IAT sensor
•ECM
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 IAT sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ON ignition switch.
3) Check intake air temp. displayed on scan tool.
Is –40
°C (–40 °F) indicated? Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-75
3IAT sensor voltage check
1) Disconnect connector from MAF and IAT sensor with
ignition switch turned OFF.
2) Check for proper connection to MAF and IAT sensor at “BLK/YEL” and “GRY/BLU” wire terminals.
3) If OK, then turn ON igniti on switch, measure voltage
between “BLK/YEL” wire terminal of MAF and IAT
sensor connector (1) and vehicle body ground.
Is voltage about 4 – 6 V? Go to Step 7. Go to Step 4.
4 ECM voltage 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- 25” terminal.
4) If OK, then turn ON igniti on switch, measure voltage
between “C37-25” terminal of ECM connector and
vehicle body ground.
Is voltage about 4 – 6 V? “BLK/YEL” wire is open
circuit. If wire and
connection are OK, go
to Step 5.
Go to Step 5.
5 Wire circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Turn ON ignition switch.
3) Measure voltage between “BLK/YEL” wire terminal of MAF and IAT sensor connector and vehicle body
ground.
Is voltage about 0 V? Go to Step 6.
“BLK/YEL” wire is
shorted to other circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
6 Wire circuit check
1) Measure resistance between “C37-25” terminal of ECM
connector and “BLK/YEL” wire terminal of MAF and IAT
sensor connector with ignition switch turned OFF.
Is resistance below 5
Ω? Go to Step 7. “BLK/YEL” wire is high
resistance circuit.
7 Ground circuit check
1) Connect connectors to ECM.
2) Measure resistance between “GRY/BLU” wire terminal
of MAF and IAT sensor connector and vehicle body
ground with ignition switch turned OFF.
Is resistance below 5
Ω? Go to Step 9. Go to Step 8.
Step Action Yes No
I4RS0B110020-01

Downloaded from www.Manualslib.com manuals search engine 1A-76 Engine General Information and Diagnosis:
DTC P0116: Engine Coolant Temperature Circuit Range / PerformanceS7RS0B1104026
Wiring Diagram
DTC Detecting Condition and Trouble Area8
Ground circuit check
1) Remove ECM from its br acket with ECM connectors
connected.
2) Measure resistance between “C37-55” terminal of ECM connector and vehicle body ground.
Is resistance below 5
Ω? “GRY/BLU” wire and/or
“ORN” wire is open
circuit or high resistance
circuit. Poor “C37-55”
connection.
Faulty ECM ground
circuit. If circuit is OK,
substitute a known-
good ECM and recheck.
9 IAT sensor for performance check
1) Check IAT sensor according to “MAF and IAT Sensor
Inspection in Section 1C”.
Is it in good condition? Substitute a known-
good ECM and recheck.
Replace MAF and IAT
sensor.
Step Action Yes No
C37-55ORNORN
3
1
2
5V
C37-24LT GRN
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
I4RS0A110025-01
1. ECT sensor
2. ECM3. To other sensors
DTC detecting condition Trouble area
ECT sensor values is less than –5 °C, 23 °F while engine is
running under more than specified engine load (more than 1000
rpm) for 2 to 1116 min (depending on ECT at engine start)
continuously from engine start.
(*2 driving cycle detecting logi c, monitoring once per driving
cycle) • ECT sensor
• ECT sensor circuit
•Thermostat
•ECM

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

Downloaded from www.Manualslib.com manuals search engine 1A-124 Engine General Information and Diagnosis:
DTC P0480: Fan 1 (Radiator Cooling Fan) Control CircuitS7RS0B1104050
Wiring Diagram5
Wire circuit check
1) Connect connector to purge control valve with ignition
switch turned OFF.
2) Turn ON ignition switch and measure voltage between “C37-29” terminal of ECM connector and vehicle body
ground.
Is it voltage 10 – 14 V? Go to Step 6. “BLU/BLK” wire is open
circuit.
6 EVAP canister purge control valve check
1) Check EVAP canister purge control valve referring to
“EVAP Canister Purge Valve Inspection in Section 1B”.
Is it in good condition? Go to Step 7. Faulty EVAP canister
purge control valve.
7 EVAP canister purge control circuit check
1) With ignition switch turn OFF, measure resistance
between “E23-1/16” terminal and “C37-29” terminal of
ECM connector.
Is resistance below 40
Ω at 20 °C, 68 °F? Faulty ECM. Substitute
a known-good ECM and
recheck.
“BLK/RED” and/or
“BLU/BLK” wire are high
resistance circuit.
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
BLK/REDBLK/RED
BLK/YELBLK/YEL
BLK/YEL
BRN/WHT
12V
5V5V
2
8
E23-1
E23-60
C37-58
C37-15 C37-30
BLK/ORN
BLKBLKE23-31BLK
BLK/RED
LT GRN
BLK/REDE23-16
E23-46
L+
L–
H–
H
+
BLU/RED
BLK
BLUWHTBLK
BLU/BLK
BLU/RED
4
GRN
GRY
E23-48
LT GRN
ORN
C37-24
C37-55
35
6
7
10
9
1
I6RS0C110022-02
1. Individual circuit fuse box No.1
5. Radiator cooling fan relay No. 3 9. “FI” fuse
2. Main relay 6. Radiator cooling fan motor10. “RDTR FAN” fuse
3. Radiator cooling fan relay No. 1 7. ECT sensor
4. Radiator cooling fan relay No. 2 8. ECM

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-125
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure1) Turn OFF ignition switch.
2) Clear DTC with ignition switch turned ON.
3) Run engine at idle speed.
4) Check DTC.
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 detecting condition Trouble area
Monitor signal of radiator cooling fan relay is different from
command signal.
(1 driving cycle detection logic) • Radiator cooling fan relay circuit malfunction
• Radiator cooling fa
n relay malfunction
• ECM malfunction
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 Circuit fuse check
1) Check “RDTR FAN” fuse (1) in individual circuit fuse box
No.1 with ignition switch turned OFF.
Is “RDTR FAN” fuse in good condition? Go to Step 3.
Check for short in
circuits connected to
this fuse.
1
I4RS0A110022-01