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-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