maf sensor SUZUKI SWIFT 2006 2.G Service User Guide

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-33
Scan Tool DataS7RS0B1104007
As the data values are standard values estimated on the basis of values obtained from the normally operating vehicles
by using a scan tool, use them as re ference values. Even when the vehicle is in good condition, there may be cases
where the checked value does not fall within each specified data range. Therefore, judgment as abnormal should not
be made by checking with these data alone.
Also, conditions that can be checked by the scan tool are those detected by ECM and output from ECM as commands
and there may be cases where the engine or actuator is not operating (in the condition) as indicated by the scan tool.
Be sure to use the timing light to check the ignition timing.
NOTE
• There are two types of OBD system depending on the vehicle specification.
For details, refer to “Precaution on On-Board Diagnostic (OBD) System”.
• With the generic scan tool, only star (*) marked data in the following table can be read.
• When checking the data with the engine running at idle or racing, be sure to shift M/T gear to the neutral position and A/T gear to the “Park” position and pull the parking brake fully. Also, if nothing
or “no load” is indicated, turn O FF A/C (if equipped with A/C), all electric loads, P/S and all the other
necessary switches.

) P2122 Throttle/pedal position sensor/switch/“D” (main)
circuit low input
• ECM turns off throttle actuator control relay and throttle valve is fixed at the specified opening from
its completely closed position (default opening).
For details, refer to “Description of Electric
Throttle Body System”.
• ECM controls fuel cut at specified engine speed.
• ECM stops air/fuel ratio control.
)
P2123 Throttle/pedal position sensor/switch/“D” (main)
circuit high input
) P2127 Throttle/pedal position sensor/switch/“E” (sub)
circuit low input
) P2128 Throttle/pedal position sensor/switch/“E” (sub)
circuit high input
) P2135 Throttle/pedal position sensor/switch/“A”/“B”
(main) / (sub) voltage correction
) P2138 Throttle pedal position sensor/switch “D”/“E”
(main) / (sub) voltage correlation
) P2227 Barometric pressure sensor performance problem ECM controls actuators assuming that barometric
pressure is 101.33 kPa (762 mmHg).
DTC No. Detected item Fail-safe operation
Scan tool data
Vehicle condition Normal condition /
reference values
* ) COOLANT TEMP At specified idle speed after warming up 80 – 100 °C, 176 – 212 °F
* ) INTAKE AIR TEMP. At specifie d idle speed after warming up –5
°C (23 °F) + environmental
temp. to 40 °C (104 °F) +
environmental temp.
* ) ENGINE SPEED It idling with no load after warming upDesired idle speed ± 50 rpm
) INJ PULSE WIDTH At specified idle speed with no load after warming up
2.0 – 4.0 msec.
At 2500 r/min. with no load after warming up 2.0 – 3.6 msec.
) DESIRED IDLE It idling with radiator cooling fan stopped and all electrical
parts turned OFF after warming up, M/T at neutral 700 rpm
* ) SHORT FT B1 At specified idle speed after warming up –20 – +20%
* ) LONG FT B1 At specified idle speed after warming up –20 – +20%
) TOTAL FUEL TRIM
B1 At specified idle speed after warming up
–35 – +35%
* ) MAF At specified idle speed wit
h no load after warming up 1.0 – 4.0 g/s 0.14 – 0.52 lb/
min.
At 2500 r/min. with no load after warming up 4.0 – 12.0 g/s 0.53 – 1.58 lb/
min.
* ) CALC LOAD At specified idle speed with no load after warming up
18 – 28%
At 2500 r/min. with no load after warming up 13 – 23%
* )
THROTTLE
POSITION Ignition switch ON /
warmed up engine
stoppedAccelerator pedal released
0 – 5%
Accelerator pedal depressed
fully 90 – 100%

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-35
Scan Tool Data Definitions
COOLANT TEMP (ENGINE COOLANT
TEMPERATURE, °C, °F)
It is detected by engine coolant temp. sensor.
INTAKE AIR TEMP. ( °C, °F)
It is detected by intake air temp. sensor.
ENGINE SPEED (rpm)
It is computed by reference pulses from the camshaft
position sensor.
INJ PULSE WIDTH (FUEL INJECTION PULSE WIDTH,
msec.)
This parameter indicates time of the injector drive (valve
opening) pulse which is output from ECM (but injector
drive time of NO.1 cylinder fo r multiport fuel injection).
DESIRED IDLE (DESIRED IDLE SPEED, rpm)
The Desired Idle Speed is an ECM internal parameter
which indicates the ECM requested idle. If the engine is
not running, this number is not valid.
SHORT FT B1 (SHORT TERM FUEL TRIM, %)
Short term fuel trim valu e represents short term
corrections to the air/fuel mixture computation. A value
of 0 indicates no correction, a value greater than 0
means an enrichment correction, and a value less than 0
implies an enleanment correction. LONG FT B1 (LONG TERM FUEL TRIM, %)
Long term fuel trim value represents long term
corrections to the air/fuel mixture computation. A value
of 0 indicates no correction, a value greater than 0
means an enrichment correction, and a value less than 0
implies an enleanment correction.
TOTAL FUEL TRIM B1 (%)
The value of Total Fuel Trim is obtained by calculating
based on values of Short Term Fuel Trim and Long Term
Fuel Trim. This value indica
tes how much correction is
necessary to keep the air/fuel mixture stoichiometrical.
MAF (MASS AIR FLOW RATE, g/s, lb/min.)
It represents total mass of air entering intake manifold
which is measured by mass air flow sensor.
CALC LOAD (CALCULATED LOAD VALUE, %)
Engine load displayed as a percentage of maximum
possible load. Value is calculated mathematically using
the formula: actual (current) intake air volume ÷
maximum possible intake air volume × 100%
THROTTLE POS (ABSOLUTE THROTTLE POSITION,
%)
When throttle position sensor is at fully closed position,
throttle opening is indicated as 0 – 5% and 90 – 100%
full open position.
O2S SENSOR B1 S1 (HEA TED OXYGEN SENSOR-1,
V)
It indicates output voltage of HO2S-1 installed on
exhaust manifold (pre-catalyst).
)
TP SENSOR 2 VOLT Ignition switch ON after
warmed up engine Accelerator pedal released
1.4 – 1.8 V
Accelerator pedal depressed
fully 3.58 – 4.76 V
) APP SENSOR 1
VOLT Ignition switch ON after
warmed up engineAccelerator pedal released
0.5 – 0.9 V
Accelerator pedal depressed
fully 3.277 – 3.915 V
) APP SENSOR 2
VOLT Ignition switch ON after
warmed up engineAccelerator pedal released
1.3 – 1.7 V
Accelerator pedal depressed
fully 4.077 – 4.715 V
) ACCEL POSITION Ignition switch ON after
warmed up engine Accelerator pedal released
0 – 5%
Accelerator pedal depressed
fully 90 – 100%
) THROTTLE TARGET
POSI Ignition switch ON after
warmed up engineAccelerator pedal released
0 – 5%
Accelerator pedal depressed
fully 90 – 100%
) BATTERY
CURRENT At specified idle speed with no load after warming up
5.0 – 60.0 A
) GENERATOR CONT
DUTY (GENERATOR
CONTROL DUTY) At specified idle speed with no load after warming up
20.0 – 100.0%
) GENERATOR FIELD
DUTY (GENERATOR
FIELD COIL DUTY) At spe
cified idle speed with no load after warming up
20.0 – 100.0%
Scan tool data
Vehicle condition Normal condition /
reference values

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-41
Engine Symptom DiagnosisS7RS0B1104010
Perform troubleshooting referring to the followings when ECM has detected no DTC and no abnormality has been
found in “Visual Inspection” and “Engine Basic Inspection”.
Condition Possible cause Correction / Reference Item
Hard starting (Engine
cranks OK) Faulty spark plug
“Spark Plug Inspection in Section 1H”
Leaky high-tension cord “High-Tension Cord Inspection in Section 1H”
Loose connection or disconnection of
high-tension cord(s) or lead wire(s) “High-Tension Cord Removal and Installation
in Section 1H”
Faulty ignition coil “Ignition Coil Assembly (Including ignitor)
Inspection in Section 1H”
Dirty or clogged fuel hose or pipe “Fuel Pressure Check”
Malfunctioning fuel pump “Fuel Pressure Check”
Air drawn in through intake manifold
gasket or throttle body gasket
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty ECT sensor or MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty ECM
Low compression “Compression Check in Section 1D”
Poor spark plug tightening or faulty
gasket “Spark Plug Removal and Installation in
Section 1H”
Compression leak from valve seat “Valves and Valve Guides Inspection in
Section 1D”
Sticky valve stem “Valves and Valve Guides Inspection in
Section 1D”
Weak or damaged valve springs “Valve Spring Inspection in Section 1D”
Compression leak at cylinder head
gasket “Cylinder Head Inspection in Section 1D”
Sticking or damaged piston ring “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn piston, ring or cylinder “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Malfunctioning PCV valve “PCV Valve Inspection in Section 1B”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Faulty EGR system “EGR System Inspection in Section 1B”
Low oil pressure Improper oil viscosity “Engine Oil and Filter Change in Section 0B”
Malfunctioning oil pressure switch “Oil Pressure Switch Inspection in Section 9C”
Clogged oil strainer “Oil Pan and Oil Pump Strainer Cleaning in
Section 1E”
Functional deterioration of oil pump “Oil Pump Inspection in Section 1E”
Worn oil pump relief valve “Oil Pump Inspection in Section 1E”
Excessive clearance in various sliding
parts
Engine noise – Valve
noise
NOTE
Before checking
mechanical noise, make
sure that:
• Specified spark plug is used.
• Specified fuel is used.

Improper valve lash “Camshaft, Tappet and Shim Inspection in
Section 1D”
Worn valve stem and guide “Valves and Valve Guides Inspection in
Section 1D”
Weak or broken valve spring “Valve Spring Inspection in Section 1D”
Warped or bent valve “Valves and Valve Guides Inspection in
Section 1D”

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-43
Poor gasoline mileageLeaks or loose connection of high-
tension cord “High-Tension Cord Removal and Installation
in Section 1H”
Faulty spark plug (improper gap, heavy
deposits and burned electrodes, etc.) “Spark Plug Inspection in Section 1H”
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
High idle speed Condition “Improper engine idling or engine
fails to idle”
Poor performance of ECT sensor or
MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty fuel injector(s) “Fuel Injector Circuit Check”
Faulty ECM
Low compression “Compression Check in Section 1D”
Poor valve seating “Valves and Valve Guides Inspection in
Section 1D”
Dragging brakes Condition “Dragging brakes” in “Brakes
Symptom Diagnosis in Section 4A”
Slipping clutch Condition “Slipping clutch” in “Clutch System
Symptom Diagnosis in Section 5C”
Thermostat out of order “Thermostat Inspection in Section 1F”
Improper tire pressure “Tires Description in Section 2D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Excessive engine oil
consumption – Oil
leakage Blown cylinder head gasket
“Cylinder Head Inspection in Section 1D”
Leaky camshaft oil seals “Camshaft, Tappet and Shim Inspection in
Section 1D”
Excessive engine oil
consumption – Oil
entering combustion
chamber Sticky piston ring
“Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn piston and cylinder “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn piston ring groove and ring “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Improper location of piston ring gap “Pistons, Piston Rings, Connecting Rods and
Cylinders Disassembly and Assembly in
Section 1D”
Worn or damaged valve stem seal “Valves and Valve Guides Inspection in
Section 1D”
Worn valve stem “Valves and Valve Guides Inspection in
Section 1D”
Condition Possible cause Correction / Reference Item

Downloaded from www.Manualslib.com manuals search engine 1A-44 Engine General Information and Diagnosis:
Engine hesitates –
Momentary lack of
response as accelerator
is depressed. Can occur
at all vehicle speeds.
Usually most severe when
first trying to make
vehicle move, as from a
stop sign.Spark plug faulty
“Spark Plug Inspection in Section 1H”
Leaky high-tension cord “High-Tension Cord Inspection in Section 1H”
Fuel pressure out of specification “Fuel Pressure Check”
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
Poor performance of ECT sensor or
MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty fuel injector “Fuel Injector Circuit Check”
Faulty ECM
Engine overheating Condition “Engine overheating”
Low compression “Compression Check in Section 1D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Surge – Engine power
variation under steady
throttle or cruise. Feels
like vehicle speeds up
and down with no change
in accelerator pedal. Leaky or loosely connected high-tension
cord
“High-Tension Cord Removal and Installation
in Section 1H”
Faulty spark plug (excess carbon
deposits, improper gap, burned
electrodes, etc.) “Spark Plug Inspection in Section 1H”
Variable fuel pressure “Fuel Pressure Check”
Kinky or damaged fuel hose and lines
Faulty fuel pump (clogged fuel filter)
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
Poor performance of MAF sensor “MAF and IAT Sensor Inspection in Section
1C”
Faulty fuel injector “Fuel Injector Circuit Check”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty ECM
Excessive detonation –
Engine makes
continuously sharp
metallic knocks that
change with throttle
opening. Sounds like pop
corn popping. Faulty spark plug
“Spark Plug Inspection in Section 1H”
Loose connection of high-tension cord “High-Tension Cord Removal and Installation
in Section 1H”
Engine overheating Condition “Engine overheating”
Clogged fuel filter (faulty fuel pump) or
fuel lines “Fuel Pressure Check” or “Fuel Pump and Its
Circuit Check”
Air drawn in through intake manifold or
throttle body gasket
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
Poor performance of knock sensor, ECT
sensor or MAF sensor “DTC P0327 / P0328: Knock Sensor 1 Circuit
Low / High”, “ECT Sensor Inspection in
Section 1C” or “MAF and IAT Sensor
Inspection in Section 1C”
Faulty fuel injector(s) “Fuel Injector Circuit Check”
Faulty ECM
Excessive combustion chamber
deposits “Cylinders, Pistons and Piston Rings
Inspection in Section 1D” and/or “Piston Pins
and Connecting Rods In
spection in Section
1D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Condition Possible cause Correction / Reference Item

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-45
Engine has no powerFaulty spark plug “Spark Plug Inspection in Section 1H”
Faulty ignition coil with ignitor “Ignition Coil Assembly (Including ignitor)
Inspection in Section 1H”
Leaks, loose connection or
disconnection of high-tension cord “High-Tension Cord Removal and Installation
in Section 1H”
Faulty knock sensor “DTC P0327 / P0328: Knock Sensor 1 Circuit
Low / High”
Clogged fuel hose or pipe “Fuel Pressure Check”
Malfunctioning fuel pump “Fuel Pump and Its Circuit Check”
Air drawn in through intake manifold
gasket or throttle body gasket
Engine overheating Condition “Engine overheating”
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
Poor performance of ECT sensor or
MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty fuel injector(s) “Fuel Injector Circuit Check”
Faulty ECM
Dragging brakes Condition “Dragging brakes” in “Brakes
Symptom Diagnosis in Section 4A”
Slipping clutch Condition “Slipping clutch” in “Clutch System
Symptom Diagnosis in Section 5C”
Low compression “Compression Check in Section 1D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Improper engine idling or
engine fails to idle Faulty spark plug
“Spark Plug Inspection in Section 1H”
Leaky or disconnected high-tension cord “High-Tension Cord Removal and Installation
in Section 1H”
Faulty ignition coil with ignitor “Ignition Coil Assembly (Including ignitor)
Inspection in Section 1H”
Fuel pressure out of specification “Fuel Pressure Check”
Leaky manifold, throttle body, or cylinder
head gasket
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
Faulty evaporative emission control
system “EVAP Canister Purge Inspection in Section
1B”
Faulty EGR system “EGR System Inspection in Section 1B”
Faulty fuel injector(s) “Fuel Injector Circuit Check”
Poor performance of ECT sensor or
MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty ECM
Loose connection or disconnection of
vacuum hoses
Malfunctioning PCV valve “PCV Valve Inspection in Section 1B”
Engine overheating Condition “Engine overheating”
Low compression “Compression Check in Section 1D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Condition Possible cause Correction / Reference Item

Downloaded from www.Manualslib.com manuals search engine 1A-46 Engine General Information and Diagnosis:
Excessive hydrocarbon
(HC) emission or carbon
monoxide (CO)Faulty spark plug
“Spark Plug Inspection in Section 1H”
Leaky or disconnected high-tension cord “High-Tension Cord Removal and Installation
in Section 1H”
Faulty ignition coil with ignitor “Ignition Coil Assembly (Including ignitor)
Inspection in Section 1H”
Low compression “Compression Check in Section 1D”
Lead contamination of three way
catalytic converter Check for absence of f
iller neck restrictor.
Faulty evaporative emission control
system “EVAP Canister Purge Inspection in Section
1B”
Fuel pressure out of specification “Fuel Pressure Check”
Closed loop system (A/F feedback
compensation) fails (Faulty TP sensor,
Poor performance of ECT sensor or
MAF sensor) “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”, “ECT Sensor
Inspection in Section 1C” or “MAF and IAT
Sensor Inspection in Section 1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty injector(s) “Fuel Injector Circuit Check”
Faulty ECM
Engine not at normal operating
temperature
Clogged air cleaner “Air Cleaner Element Inspection and Cleaning
in Section 1D”
Vacuum leaks “Engine Vacuum Check in Section 1D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Excessive nitrogen
oxides (NOx) emission Improper ignition timing
“Ignition Timing Inspection in Section 1H”
Lead contamination of catalytic
converter Check for absence of f
iller neck restrictor.
Faulty EGR system “EGR System Inspection in Section 1B”
Fuel pressure out of specification “Fuel Pressure Check”
Closed loop system (A/F feedback
compensation) fails (Faulty TP sensor,
Poor performance of ECT sensor or
MAF sensor) “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”, “ECT Sensor
Inspection in Section 1C” or “MAF and IAT
Sensor Inspection in Section 1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty injector(s) “Fuel Injector Circuit Check”
Faulty ECM
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Condition Possible cause Correction / Reference Item

Downloaded from www.Manualslib.com manuals search engine 1A-58 Engine General Information and Diagnosis:
DTC P0101: Mass or Volume Air Flow Circuit Range / PerformanceS7RS0B1104017
Wiring Diagram
DTC Detecting Condition and Trouble Area
E23C37
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/WHT
BLK/RED
BLK/RED
WHT
BLK/YELBLK/YEL
BLK/YEL
GRN
BRN/WHT
12V 5V
5V
2 3 4
E23-29
E23-60
E23-1
E23-16
BLK/ORN
BLKBLK
BLK/RED
BLK/YELGRY/BLU
ORN
1BLK/RED
5
E23-31BLK
ORN
GRY
GRN/BLK
C37-58
C37-15
C37-30
C37-26
C37-27
C37-25
C37-55
I6RS0C110014-01
1. MAF and IAT sensor
3. Main relay5. To other sensors
2. Ignition switch 4. ECM
DTC detecting condition Trouble area
• MAF volume is greater than 20 g/sec even if engine revolution is less than 900 rpm and intake manifold
pressure is less than 40 kPa (5.80 psi) with TP less than
1.5 °.
• MAF volume is lower than 10 g/sec even if engine
revolution is more than 2500 rpm and intake manifold
pressure is more than 60 kPa (8.70 psi) with TP more than
12 °.
(2 driving cycle detection logic) • Air intake system (clog or leakage)
• MAF sensor circuit
•MAF sensor
• TP sensor and/or its circuit
• MAP sensor and/or its circuit
•ECM

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-59
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 the 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: 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 and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature. (ECT approx. 90 – 95 °C, 194 – 203 °F)
4) Drive vehicle with engine speed: more than 2500 rpm for 1 min.
5) Increase vehicle speed to 80 km/h (45 mile/h) at 5th gear or D range.
6) Release accelerator pedal to decrease vehicle speed to 40 km/h (25 mile/h).
7) Stop vehicle and run it idle for 1 min.
8) 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 Visual inspection
Check MAF sensor and air intake system for:
• Objects which block measuring duct and resistor of MAF
sensor.
• Other air flow which does not pass the MAF sensor.
Are they in good condition? Go to Step 3.
Repair or replace.
3 MAF sensor and its circuit check
1) With ignition switch turned OFF, connect scan tool.
2) Start engine and warm up to normal operation
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 11. Go to Step 4.

Downloaded from www.Manualslib.com manuals search engine 1A-60 Engine General Information and Diagnosis:
4MAF sensor output voltage check
1) Turn OFF ignition switch.
2) Remove ECM from its br acket with ECM connectors
connected.
3) Measure voltage between “C37-26” and “C37-27” terminals of ECM connector referring to “MAF and IAT
Sensor On-Vehicle Inspection in Section 1C”.
Is each value within specified range? Poor “C37-26” and/or
“C37-27” terminal
connection.
If OK, substitute a
known-good ECM and
recheck.
Go to Step 5.
5 MAF sensor power supply voltage check
1) Disconnect connector from MAF and IAT sensor with
ignition switch turned OFF.
2) Turn ON ignition switch, measure voltage between engine ground and “BLK/RED” wire terminal (2) of MAF
and IAT sensor connector (1).
Is voltage 10 – 14 V? Go to Step 6. “BLK/RED” wire is open
circuit.
6 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 8.
Go to Step 7.
7 Ground circuit check
1) Measure resistance between “C37-27” terminal of ECM
connector and vehicle body 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 is
open or high resistance.
If wires are OK,
substitute a known-
good ECM and recheck.
8 MAF sensor signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Turn ON ignition switch, measure voltage between “GRN/BLK” wire terminal of MAF and IAT sensor
connector and engine ground.
Is voltage 0 V? Go to Step 9. “GRN/BLK” wire is
shorted to other circuit.
9 MAF sensor signal circuit check
1) Turn OFF ignition switch, measure resistance between
“GRN/BLK” wire terminal of MAF and IAT sensor
connector and engine ground.
Is resistance infinity? Go to Step 10. “GRN/BLK” wire is
shorted to ground
circuit.
Step Action Yes No
I4RS0A110020-01