Condition
Engine overheating
Poor gasoline mileage
Excessive engine oil
consumption – Oil
leakage
Possible cause
Inoperative thermostat
Poor water pump performance
Clogged or leaky radiator
Improper engine oil grade
Clogged oil filter or oil strainer
Poor oil pump performance
Faulty radiator cooling fan control
system
Dragging brakes
Slipping clutch (for M/T model)
Blown cylinder head gasket
Air mixed in cooling system
Leaks or loose connection of high-
tension cord
Faulty spark plug (improper gap, heavy
deposits and burned electrodes, etc.)
Malfunctioning EGR valve
High idle speed
Poor performance of ECT sensor, MAF
sensor
Faulty electric throttle body assembly
Faulty APP sensor assembly
Faulty fuel injector(s)
Faulty ECM
Low compression
Poor valve seating
Dragging brakes
Slipping clutch (for M/T model)
Thermostat out of order
Improper tire pressure
Camshaft position control (VVT) system
out of order (for engine with VVT
system)
Blown cylinder head gasket
Leaky camshaft oil seals
Engine General Information and Diagnosis:
Correction / Reference Item
"Thermostat Inspection in Section 1F"
"Water Pump Inspection in Section 1F"
"Radiator On-Vehicle Inspection and Cleaning
in Section 1F"
"Engine Oil and Filter Change in Section 0B"
"Oil Pressure Check in Section 1E"
"Oil Pressure Check in Section 1E"
"Radiator Cooling Fan Control System Check"
Condition "Dragging brakes" in "Brakes
Symptom Diagnosis in Section 4A"
Condition "Slipping clutch" in "Clutch System
Symptom Diagnosis in Section 5C" for M/T
model
"Cylinder Head Inspection in Section 1D"
"High-Tension Cord Removal and Installation
in Section 1H"
"Spark Plug Inspection in Section 1H"
"EGR Valve Inspection (If Equipped) in Section
1B"
Condition "Improper engine idling or engine
fails to idle"
"Engine Coolant Temperature (ECT) Sensor
Inspection in Section 1C", or "Intake Air
Temperature (IAT) Sensor Inspection in
Section 1C"
"Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C"
"Accelerator Pedal Position (APP) Sensor
Assembly Inspection in Section 1C"
"Fuel Injector Circuit Check"
"Compression Check in Section 1D"
"Valves and Valve Guides Inspection in
Section 1D"
Condition "Dragging brakes" in "Brakes
Symptom Diagnosis in Section 4A"
Condition "Slipping clutch" in "Clutch System
Symptom Diagnosis in Section 5C" for M/T
model
"Thermostat Inspection in Section 1F"
"Tires Description in Section 2D"
"Oil Control Valve Inspection (For Engine with
VVT) in Section 1D"
"Cylinder Head Inspection in Section 1D"
"Camshaft, Tappet and Shim Inspection in
Section 1D"
1A-47