MAF SENSOR inspection SUZUKI SWIFT 2006 2.G Service User Guide

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-63
DTC P0103: Mass or Volume Air Flow Circuit High InputS7RS0B1104019
Wiring Diagram
Refer to “DTC P0101: Mass or Volume Air Flow 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.

DTC detecting condition Trouble area
MAF sensor output voltage is higher than 4.85 V for 0.5 seconds
continuously.
(1 driving cycle detection logic) • Open or short in MAF sensor circuit
• MAF 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 MAF sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Start engine and check MAF value displayed on scan tool. (Refer to “Scan Tool Data” for normal value.)
Is normal value indicated? Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
Go to Step 3.
3 MAF sensor power supply voltage check
1) Disconnect connector from MAF and IAT sensor with
ignition switch tuned OFF.
2) Turn ON ignition switch, measure voltage between engine ground and “BLK/RED” wire terminal of MAF and
IAT sensor connector.
Is voltage 10 – 14 V? Go to Step 4.
“BLK/RED” wire is open
circuit.
4 MAF sensor ground circuit check
1) Turn OFF ignition switch, measure resistance between
“GRY” wire terminal of MAF and IAT sensor connector
and engine ground.
Is resistance below 5
Ω? Go to Step 6. Go to Step 5.
5 Ground circuit check
1) Remove ECM from its br acket with ECM connectors
connected.
2) Measure resistance between “C37-27” terminal of ECM connector and engine ground.
Is resistance below 5
Ω? “GRY” wire is open or
high resistance circuit.
ECM grounds “E23-31”,
“C37-58”, “C37-15” and/
or “C37-30” circuit are
open or high resistance.
If wires are OK,
substitute a known-
good ECM and recheck.

Downloaded from www.Manualslib.com manuals search engine 1A-64 Engine General Information and Diagnosis:
DTC P0106: Manifold Absolute Pressure / Barometric Pressure Circuit Range / PerformanceS7RS0B1104020
Wiring Diagram
DTC Detecting Condition and Trouble Area6
MAF sensor signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure voltage between “GRY/BLK” wire terminal of MAF and IAT sensor connector and engine ground.
Is voltage 0 V? Go to Step 7. “GRY/BLK” wire is
shorted to other circuit.
7 MAF sensor output signal check
1) Connect connector to MAF and IAT sensor and ECM
with ignition swit ch turned OFF.
2) Measure voltage between “C37-26” and “C37-27” terminal of ECM connector referring to “MAF and IAT
Sensor On-Vehicle Inspection in Section 1C”.
Is each value within specified range? Substitute a known-
good ECM and recheck.
Faulty MAF and IAT
sensor.
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
4
C37-58
C37-15 C37-30
BLK/ORN
BLKBLKE23-31 BLK
1
2
3
GRY/REDGRY/RED
5V
5VC37-14
C37-53
C37-55
RED/BLK
ORNORN
I6RS0C110008-02
1. Manifold absolute pressure sensor
3. To other sensors
2. To A/C refrigerant pressure sensor (if equipped with A/C) 4. ECM
DTC detecting condition Trouble area
• Difference between Max. manifold absolute pressure value and Min. manifold pressure value is less than 1.3
kPa (0.19 psi) when engine running at idle speed.
• Difference between barometric pressure value and manifold pressure value is less than 33.3 kPa (4.83 psi)
for 5 sec. at 2000 r/mini. or more.
(2 driving cycle detection logic) • Manifold absolute pressure sensor
• Manifold absolute pressure sensor vacuum passage
• Air intake system
•ECM

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DTC P0111: Intake Air Temperature Sensor 1 Circuit Range / PerformanceS7RS0B1104023
Wiring Diagram6
Ground circuit check
1) Measure resistance between “C37-55” terminal of ECM
connector and vehicle body ground.
Is resistance below 5
Ω? “ORN” wire is open or
high resistance circuit.
ECM grounds “E23-31”,
“C37-58”, “C37-15” and/
or “C37-30” circuit are
open or high resistance.
If wires are OK,
substitute a known-
good ECM and recheck.
7 MAP sensor signal circuit check
1) Turn ON ignition switch.
2) Measure voltage between “RED/BLK” wire terminal of
MAP sensor connector and engine ground.
Is voltage 4 – 6 V? Go to Step 9. Go to Step 8.
8 MAP sensor signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “RED/BLK” wire terminal of MAP sensor connector and “C37-53” terminal of ECM
connector.
Is resistance below 2
Ω? “RED/BLK” wire is
shorted to power supply
circuit.
“RED/BLK” wire is open
or high resistance
circuit.
9 MAP sensor output signal check
1) Check MAP sensor acco rding to “MAP Sensor
Inspection in Section 1C”.
Is it in good condition? Substitute a known-
good ECM and recheck.
Faulty MAP sensor.
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
5V
2
BLK/YEL
GRY/BLU
GRY
ORN
1
GRN/BLK
C37-25
C37-55 3 4ORN
C37-26
C37-27
BLK/RED
I4RS0B110018-01
1. MAF and IAT sensor
3. To other sensors
2. ECM 4. From main relay

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 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-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-98 Engine General Information and Diagnosis:
DTC P0171 / P0172: Fuel System Too Lean / RichS7RS0B1104036
DTC Detecting Condition and Trouble Area
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.

NOTE
Check to make sure that following conditions ar e 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: 40 °C (104 °F) to 120 °C (248 °F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)

3 Wire circuit check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors
connected.
3) Measure resistance between “BRN” wire terminal of HO2S-2 connector and “C37-11” terminal of ECM
connector.
Is resistance less than 5
Ω? Go to Step 4. “BRN” wire is high
resistance circuit or
open circuit. Poor “C37-
11” terminal connection.
If they are OK,
substitute a known-
good ECM and recheck.
4 HO2S-2 signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure voltage between “BRN” wire terminal of HO2S- 2 connector and vehicle body ground.
Is voltage 0 V? Go to Step 5. “BRN” wire is shorted to
other circuit.
5 HO2S-2 heater circuit check
1) Check HO2S-2 heater circuit referring to “DTC P0037 /
P0038: HO2S Heater Control Circuit Low / High
(Sensor-2)”.
Is circuit in good condition? Go to Step 6. Repair HO2S-2 circuit. If
circuit is OK, substitute
a known-good ECM and
recheck.
6 HO2S-2 check
1) Check HO2S-2 referring to “HO2S-1 and HO2S-2
Heater On-Vehicle Inspection in Section 1C”.
Is it in good condition? Substitute a known-
good ECM and recheck.
Replace HO2S-2.
Step Action Yes No
DTC detecting condition
Trouble area
DTC P0171:
Total fuel trim is higher than 35% or short term fuel trim is higher
than 20% for more than 1 min. continuously.
(2 driving cycle detection logic)
DTC P0172:
Total fuel trim is lower than –35% or short term fuel trim is lower
than –20% for more than 1 min. continuously.
(2 driving cycle detection logic) • Vacuum leakage
• Exhaust gas leakage
• Fuel pressure out of specification
• Fuel injector malfunction
• Heated oxygen sensor-1 malfunction
• MAF sensor malfunction
• ECT sensor malfunction

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-99
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and print Freeze Frame Data or write them down using scan tool.
3) Clear DTC using scan tool.
4) Start engine and warm up to normal operating temperature.
5) Operate vehicle with condition as noted freeze frame data for 5 min.
6) Stop vehicle and 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.

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 Is there DTC(s) other than fuel system (DTC P0171 /
P0172)? Go to applicable DTC
diag. flow.Go to Step 3.
3 Intake system and exhaust system for leakage check
Are intake system and exhaust system in good condition? Go to Step 4.
Repair or replace
defective part.
4 Fuel pressure check
1) Check fuel pressure referring to “Fuel Pressure Check”.
Is check result satisfactory? Go to Step 5.
Repair or replace
defective part.
5 Fuel injectors and its circuit check
1) Check fuel injectors referring to “Fuel Injector Inspection
in Section 1G”.
Is check result satisfactory? Go to Step 6.
Faulty injector(s) or its
circuit.
6 Visual inspection
1) Check MAF sensor and air intake system.
• Objects which block measur ing duct and resistor of
MAF sensor.
• Other air flow which does not pass MAF sensor.
Are they in good condition? Go to Step 7.
Repair or replace
defective part.
7 MAF sensor for performance check
1) With ignition switch turn ed OFF, install scan tool.
2) Start engine and warm up to normal operating temperature.
3) Check MAF value using scan tool (Refer to “Scan Tool Data” for normal value.).
Is each value within specified range? Go to Step 8.
Go to “DTC P0101:
Mass or Volume Air
Flow Circuit Range /
Performance”.
8 ECT sensor for performance check
1) Check ECT sensor referring to Step 3 and 4 of “DTC
P0118: Engine Coolant Temperature Circuit High”.
Is check result satisfactory? Go to Step 9.
Faulty ECT sensor or its
circuit.

Downloaded from www.Manualslib.com manuals search engine Engine Electrical Devices: 1C-11
MAF and IAT Sensor On-Vehicle InspectionS7RS0B1306018
NOTE
Before performed this inspection, be sure to
read the “Precautions of ECM Circuit
Inspection in Section 1A”.

1) Disconnect negative (–) cable at battery.
2) Disconnect MAF and IAT sensor connector.
3) Connect voltmeter to “BLK/RED” wire terminal (2) of
MAF and IAT sensor connector (1) disconnected and
ground.
4) Turn ON ignition switch position and check that voltage is battery voltage.
If not, check if wire harness is open or connection is
poor.
5) Turn OFF ignition switch position and connect connector to MAF and IAT sensor.
6) Remove ECM from its bracket referring to “ECM Removal and Installation”.
7) Connect special tool between ECM and ECM connector referring to “Inspection of ECM and Its
Circuits in Section 1A”.
8) Turn ON ignition switch position and check MAF signal voltage between “C37-26” terminal circuit and
“C37-27” terminal circuit of special tool.
MAF signal voltage between “C37-26” terminal
circuit and “C37-27” termi nal circuit of special
tool
MAF signal voltage of MAF and IAT sensor with
ignition switch turned ON: 0.5 – 1.0 V
9) Start engine and check that voltage is lower than 5 V and it rises as engine speed increases.
MAF signal voltage between “C37-26” terminal
circuit and “C37-27” termi nal circuit of special
tool
MAF signal reference voltage of MAF and IAT
sensor at specified Idle speed: 1.3 – 1.8 V 10) If check result is not as
specified above, cause may
lie in wire harness, connec tor connection, MAF and
IAT sensor or ECM.
MAF and IAT Sensor Removal and InstallationS7RS0B1306019
CAUTION!
• Do not disassemble MAF and IAT sensor.
• Do not expose MAF and IAT sensor to any shock.
• Do not clean MAF and IAT sensor.
• If MAF and IAT sensor has been dropped, it should be replaced.
• Do not blow compressed air by using air gun or the like.
• Do not put finger or any other object into MAF and IAT sensor. Malfunction may
occur.

Removal
1) Disconnect negative (–) cable at battery.
2) Disconnect MAF and IAT sensor connector.
3) Remove air cleaner case (1).
4) Remove MAF and IAT sensor (2) from air cleaner case.
Installation
Reverse removal procedure noting the followings.
• Tighten MAF and IAT sensor screws to specified torque.
Tightening torque
MAF and IAT sensor screw (a): 1.5 N·m (0.15 kgf-
m, 1.1 lb-ft)
• Connect MAF and IAT sensor connector securely.
1. ECM
I3RB0A130009-01
“C37-27” “C37-26” 1
I4RS0A130009-01
1
2
I4RS0A130010-01
(a)
I4RS0A130011-01