2. INSPECTION
Possible Cause Action
Coolant level
is too low- Leak from the radiator
- Leak from the auxiliary reservoir
- Leak from the heater core- Replace the radiator
- Replace the auxiliary reservoir
- Replace the heater
- Leak from the coolant hose connections
- Damaged coolant hose- Reconnect the hose or replace
the clamp
- Replace the hose
- Leak from the water pump gasket
- Leak from the water pump internal seal- Replace the gasket
- Replace the water pump
- Leak from the water inlet cap
- Leak from the thermostat housing- Replace the water inlet cap
gasket
- Replace the thermostat sealing
- Incorrect tightening torque of the
cylinder head bolts
- Damaged cylinder head gasket- Tighten the bolts to the specified
torque
- Replace the cylinder head
gasket
Coolant
temperature is
too high- Coolant leakage (Coolant level is low)
- Improper coolant mixture ratio
- Kinked coolant hose- Add coolant
- Check the coolant concentration
(Anti-freeze)
- Repair or replace the hose
- Defective thermostat
- Defective water pump
- Defective radiator
- Defective auxiliary reservoir or tank cap- Replace the thermostat
- Replace the water pump
- Replace the radiator
- Replace the auxiliary reservoir
or tank cap
- Cracks on the cylinder block or cylinder
head
- Clogged coolant passages in the
cylinder block or cylinder head- Replace cylinder block or
cylinder head
- Clean the coolant passage
- Clogged radiator core - Clean the radiator core
- Improper operation of cooling fan - Replace the cooling fan or repair
the related circuit
- Defective temperature sensor or faulty
wiring- Replace the sensor or repair the
related wiring
Coolant
temperature is
too low- Thermostat is stuck open - Replace the thermostat
- Improper operation of cooling fan - Replace the cooling fan or repair
the related circuit
- Defective temperature sensor or faulty
wiring- Replace the sensor or repair the
related wiring
1745-01
1. OVERVIEW
This system purifies the exhaust gas generated by the combustion in the engine to reduce the pollutants
and noise during that arise during combustion.
Harmful materials produced in the combustion process is treated and reduced in the exhaust system.
Harmful materials discharged from the crankcase and fuel tank is drawn into the intake system again to
reduce discharge amount of harmful materials.
Emission aftertreatment system
Catalytic Converter & O2 Sensor
The catalytic converter is a monolith type purification system composed of cordierite which purifies
exhaust gas through the small holes of active monolith catalyst from the exhaust manifold. As exhaus
t
gas passes through the small holes in the layer in the middle, its CO and HC are reduced by
oxidization reaction and its NOx is reduced by reduction reaction to Pt, Ph and Pd. The oxygen
sensor sends signals for feedback and determination of catalyst condition. For detailed description,
see the corresponding section. -
The fuel evaporative gas is a gas evaporated to the atmosphere in the section between the fuel tank and
fuel line, and its main component is hydrocarbon (HC). The fuel evaporative gas is temporarily stored in
the canister, and it is drawn to the engine through the throttle body when the purge control solenoid valve
is open according to the engine operating condition.
Gas in the combustion chamber is sealed by the piston. However, gas is leaked through the gap
between the cylinder and piston and drawn into the crankcase during the compression and explosion
strokes. This gas is blow-by gas and its main components are hydrocarbon and carbon monoxide. If this
gas is drawn into the crankcase, the system can be corroded and oil can be deteriorated. Also, if this
gas is discharged into the air, it can pollute the environment. To prevent these, the blow-by gas
reduction system (also called as crankcase ventilation system) draws the blow-by gas from the
crankcase to the combustion chamber for combustion.
Purge Canister Control
Blow-by gas control system (crankcase ventilation system)
