
Downloaded from www.Manualslib.com manuals search engine 1A-42 Engine General Information and Diagnosis: 
Engine noise – Piston, 
ring and cylinder noise
NOTE
Before checking 
mechanical noise, make 
sure that:
• Specified spark plug is used.
• Specified fuel is used.
 
Worn piston, ring and cylinder bore “Cylinders, Pistons and Piston Rings 
Inspection in Section 1D”
Engine noise – 
Connecting rod noise
NOTE
Before checking 
mechanical noise, make 
sure that:
• Specified spark plug is  used.
• Specified fuel is used.
 
Worn piston, ring and cylinder bore “Cylinders, Pistons and Piston Rings 
Inspection in Section 1D”
Worn rod bearing “Crank Pin and Connecting Rod Bearings 
Inspection in Section 1D”
Worn crank pin “Crank Pin and Connecting Rod Bearings 
Inspection in Section 1D”
Loose connecting rod nuts “Pistons, Piston Rings, Connecting Rods and 
Cylinders Removal and Installation in Section 
1D”
Low oil pressure Condition “Low oil pressure”
Engine noise – 
Crankshaft noise
NOTE
Before checking 
mechanical noise, make 
sure that:
• Specified spark plug is  used.
• Specified fuel is used.
 
Low oil pressure Condition “Low oil pressure”
Worn bearing “Main Bearings Inspection in Section 1D”
Worn crankshaft journal “Crankshaft Inspection in Section 1D”
Loose bearing cap bolts “Main Bearings, Crankshaft and Cylinder Block 
Removal and Installation in Section 1D”
Excessive crankshaft thrust play “Crankshaft Inspection in Section 1D”
Engine overheating Inoperative thermostat “Thermostat Inspection in Section 1F”
Poor water pump performance “Water Pump Inspection in Section 1F”
Clogged or leaky radiator “Radiator On-Vehicle Inspection and Cleaning 
in Section 1F”
Improper engine oil grade “Engine Oil and Filter Change in Section 0B”
Clogged oil filter or oil strainer “Oil Pressure Check in Section 1E”
Poor oil pump performance “Oil Pressure Check in Section 1E”
Faulty radiator cooling fan control 
system “Radiator Cooling Fan Low Speed Control 
System Check” or “Rad
iator Cooling Fan High 
Speed Control System Check”
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”
Blown cylinder head gasket “Cylinder Head Inspection in Section 1D”
Air mixed in cooling system
Condition Possible cause Correction / Reference Item  

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-106 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 Does fuel level meter in dicate “E” level (empty)? Add fuel and recheck. Go to Step 3.
3 Fuel quality check
1) Check that there is fuel of good quality in the fuel tank.
Is it OK? Go to Step 4.
Clean in fuel system 
circuit and change fuel.
4 Ignition system check
1) Check spark plug and ignition spark of cylinder where 
misfire occurs, referring to “Spark Plug Inspection in 
Section 1H” and “Ignition Spark Test in Section 1H”.
Are they in good condition? Go to Step 5.
Faulty ignition coil, wire 
harness, spark plug or 
other system parts.
5 Fuel injector circuit check
1) Using sound scope, check each injector operating sound 
at engine cranking or idling.
Do all injectors ma ke operating sound? Go to Step 6.
Check coupler 
connection and wire 
harness of injector not 
making operating sound 
and injector itself. If OK, 
substitute a known-
good ECM and recheck.
6 Fuel pressure check
1) Check fuel pressure referring to “Fuel Pressure Check”.
Is check result satisfactory? Go to Step 7.
Repair or replace fuel 
system.
7 Fuel injector check
1) Check fuel injector(s) re ferring to “Fuel Injector 
Inspection in Section 1G”.
Is check result satisfactory? Go to Step 8.
Replace defective 
injector.
8 Ignition timing check
1) Check ignition timing referring to “Ignition Timing 
Inspection in Section 1H”.
Is check result satisfactory? Go to Step 9.
Check related sensors.
9 EGR system check
1) Check EGR system referring  to “EGR System Inspection 
in Section 1B”.
Is check result satisfactory? Go to Step 10. Repair or replace EGR 
system.
10 Exhaust system check
1) Check exhaust system for exhaust gas clogged.
Is it OK? Go to Step 11. Repair clogged of 
exhaust system.  

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  

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis:  1A-115
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 Ignition spark check
1) Check that each spark plug sparks referring to “Ignition 
Spark Test in Section 1H”.
Is check result satisfactory? Intermittent trouble. 
Check for intermittent 
referring to “Intermittent 
and Poor Connection 
Inspection in Section 
00”.Go to Step 3.
3 Ignition coil power, output and ground circuit check
1) Disconnect ignition coil connector of the cylinder found 
as faulty in Step 2.
2) Check ignition coil circuit of the cylinder found as faulty  in Step 2 for the following.
• Voltage between power circuit wire terminal of ignition coil connector and vehicle body ground is 10 – 14 V 
with ignition switch turned ON.
• Voltage between output circuit wire terminal of ignition  coil connector and vehicle body ground is 4 – 6 V with 
ignition switch turned ON.
• Resistance between ground circuit wire terminal of  ignition coil connector and vehicle body ground is less 
than 2  Ω.
Are they in good condition? Go to Step 4.
Repair or replace 
defective wire.
4 Ignition coil check
1) Replace ignition coil for No.1 and No.4 spark plugs with 
ignition coil for No.2 and No.3 spark plugs.
Is the cylinder found as faulty in good condition now? Faulty ignition coil. Go to Step 5.
5 Ignition coil output circuit check
1) Disconnect connectors from ECM.
2) Check ignition coil circuit of the cylinder found as faulty 
in Step 2 for the following.
• Resistance of output wire circuit between ignition coil 
connector and ECM connector is less than 2  Ω.
• Resistance of output wire circuit between ignition coil  connector and vehicle b ody ground is infinity.
Are they in good condition? Substitute a known-
good ECM and recheck.
Repair or replace 
defective wire.