Mitsubishi 380. Manual - part 353

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-80

COMPONENT LOCATION

M1173007400189

POSITIVE CRANKCASE VENTILATION SYSTEM 
CHECK

M1173001100232

1. Remove the positive crankcase ventilation (PCV) valve from 

the rocker cover.

2. With the engine idling, put your finger on the open end of the 

PCV valve, and check for negative pressure (vacuum).

NOTE: At this time, the plunger in the PCV valve should 
move back and forth as the open end is covered and uncov-
ered.

3. If negative pressure is not felt, clean or replace the PCV 

valve. Inspect the vacuum supply hose and vacuum supply 
hose port for restriction or plugged condition.

POSITIVE CRANKCASE VENTILATION VALVE 
CHECK

M1173001200228

1. Hold the positive crankcase ventilation (PCV) valve with the 

vacuum side down. Insert a thin rod, and using lamp 
pressure, depress the end of the PCV valve spring by 5 

− 10 

mm. Release pressure on the rod to see if the PCV valve 
spring will lift the rod to its original position. 

2. If the rod returns quickly to its original position, the PCV 

valve is OK. If the stick does not return quickly, clean or 
replace the PCV valve.

POSITIVE CRANKCASE

VENTILATION VALVE

07TE008A

PCV VALVE

POSITIVE 

CRANKCASE 

VENTILATION 

VALVE

6EM0400

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-81

EVAPORATIVE EMISSION CONTROL SYSTEM

GENERAL DESCRIPTION (EVAPORATIVE EMISSION SYSTEM)

M1173005100706

The evaporative emission (EVAP) system prevents 
fuel vapors generated in the fuel tank from escaping 
into the atmosphere.
Fuel vapors from the fuel tank flow through the vapor 
pipe/hose to be stored temporarily in the EVAP can-
ister. 
When the vehicle is in operation, fuel vapors stored 
in the EVAP canister flow through the EVAP purge 
solenoid, purge port and intake manifold plenum to 
the combustion chamber.

When the engine coolant temperature is low or when 
the intake air quantity is small (when the engine is at 
idle, for example), the Engine-ECU brings the EVAP 
purge solenoid into the OFF state to shut off the fuel 
vapor flow to the intake manifold plenum. This 
ensures driveability when the engine is cold or run-
ning under low load and also stabilizes the emission 
level.

SYSTEM DIAGRAM

07DB112A

EVAPORATIVE 

EMISSION 

PURGE 

SOLENOID 

ON: OPEN

ENGINE

  ECU

INTAKE AIR TEMPERATURE

SENSOR

ENGINE COOLANT 

TEMPERATURE SENSOR

MASS AIRFLOW SENSOR

MFI 

RELAY

EVAPORATIVE EMISSION 

CANISTER

FUEL

TANK

B

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-82

COMPONENT LOCATION

M1173007500205

PURGE CONTROL SYSTEM CHECK (PURGE FLOW CHECK)

M1173001400620

01DB051A

WHITE MARK

.

SOLENOID VALVE

CHAMBER

07DB115A

THROTTLE BODY

INTAKE MANIFOLD

FROM 

AIRCLEANER

TO 

COMBUSTION

CHAMBER

OFF

ON

EVAPORATIVE EMISSION 

PURGESOLENOID

(ON: OPENED)

PURGE

FLOW

INDICATOR

(MB995061)

PURGE HOSE

EVAPORATIVE EMISSION 

CANISTER

CHAMBER

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-83

Required Special Tool:
MB995061: Purge Flow Indicator
1. Disconnect the purge hose from the evaporative emission 

(EVAP) purge solenoid, and connect special tool MB995061 
between the EVAP purge solenoid and the purge hose.

2. Before inspection, set the vehicle in the following conditions:

• Engine coolant temperature: 80 − 95°C (176 − 203°F)

• Lights, electric cooling fan and accessories: OFF

• Transaxle: P range

3. Run the engine at idle for more than four minutes.

4. Check the purge flow volume when engine is revved 

suddenly several times.

Standard value: Momentarily 20 cm

3

/s (2.5 SCFH) or 

more.

5. If the purge flow volume is less than the standard value, 

check it again with the vacuum hose disconnected from the 
EVAP canister. If the purge flow volume is less than the 
standard value, check the vacuum port and the vacuum 
hose for clogging. Also check the EVAP purge solenoid. If 
the purge flow volume is at the standard value, replace the 
EVAP canister.

EVAPORATIVE EMISSION PURGE SOLENOID 
CHECK

M1173001700289

1. Disconnect the vacuum hose (black, black with red paint 

mark) from the evaporative emission (EVAP) purge 
solenoid.

NOTE: When disconnecting the vacuum hose, always place 
an identification mark so that it can be reconnected at its 
original position.

2. Disconnect the harness connector.
3. Connect a hand vacuum pump to nipple (A) of the EVAP 

purge solenoid (refer to the illustration at left).

4. As described in the chart below, check airtightness by 

applying a vacuum with voltage applied directly from the 
battery to the EVAP purge solenoid valve and without 
applying voltage.

BATTERY POSITIVE 
VOLTAGE

NORMAL CONDITION

Applied

Vacuum leaks

Not applied

Vacuum maintained

AK200339