Mitsubishi Montero (2002-2004). Manual — part 849

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-59

CRANKCASE VENTILATION SYSTEM CHECK

M1173001100027

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

the rocker cover, then reconnect the PCV valve to the
vacuum supply hose.

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 he vacuum supply hose and vacuum supply
hose port for restriction or plugged condition.

POSITIVE CRANKCASE VENTILATION (PCV)
VALVE CHECK

M1173001200024

1. Hold the PCV valve with the vacuum side down. Insert a thin

rod, and using light pressure, depress the end of the PCV
valve spring by 5

− 10 mm (0.2 − 0.3 inch). 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.

EVAPORATIVE EMISSION CONTROL SYSTEM

GENERAL DESCRIPTION (EVAPORATIVE EMISSION CONTROL SYSTEM)

M1173005100234

The evaporative control system prevents fuel vapors
generated in the fuel tank from escaping into the
atmosphere. Fuel vapors from the fuel tank flows
through the fuel tank pressure control valve and
vapor pipe/hose to be stored temporarily in the EVAP
canister. 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 PCM brings the EVAP purge solenoid
into the OFF state to shut off the fuel vapor flow to
the intake manifold plenum. This ensures the

driveability when the engine is cold or running under
low load and also stabilizes the emission level. An
EVAP ventilation solenoid is provided between the
EVAP canister and atmosphere, and used to monitor
for OBD-II EVAP leaks. This solenoid is normally
OFF. However, it turns ON when monitoring the
OBD-II EVAP leaks and shuts off the atmosphere
flow to the EVAP canister. Then the fuel tank differ-
ential pressure sensor monitors the fuel vapor pres-
sure to detect OBD-II EVAP leaks. The fuel overflow
limiter valve prevent fuel from being overfilled. The
fuel cut off valve prevents fuel leaks just if the vehicle
is rolled over in an accident.

AKX00336

PCV VALVE

AB

AKX00337

5 – 10 mm
(0.2 – 0.3 in)

PCV VALVE

VACUUM SIDE

THIN ROD
(VERY
SMOOTH)

AB

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

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SYSTEM DIAGRAM

COMPONENT LOCATION

M1173007500120

AK200802

FUEL TANK DIFFERENTIAL
PRESSURE SENSOR

LIQUID SEPARATOR

EVAP
CANISTER

EVAPORATIVE
EMISSION
PURGE
SOLENOID
ON: OPEN

PCM

BAROMETRIC PRESSURE
SENSOR

INTAKE AIR TEMPERATURE
SENSOR

ENGINE COOLANT
TEMPERATURE SENSOR

VOLUME AIRFLOW SENSOR

FUEL
TANK

MFI
RELAY

FUEL OVERFLOW
LIMITER VALVE

FUEL CUT
OFF VALVE

LEVELING VALVE

EVAPORATIVE
EMISSION
VENTILATION VALVE

AIR FILTER

EVAPORATIVE
EMISSION
VENTILATION SOLENOID
ON: CLOSED

AB

AC203904

AD

EVAPORATIVE
EMISSION
PURGE SOLENOID
VALVE

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

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PURGE CONTROL SYSTEM CHECK (PURGE FLOW CHECK)

M1173001400028

Required Special Tool:
MB995061: Purge flow indicator
1. Disconnect the purge hose from the evaporative emission

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

2. Before inspection and adjustment, set the vehicle in the

following conditions:

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

• Lights and accessories: OFF

• Transmission: P range

3. Run the engine at idle for more than four minutes.
4. Check the purge flow volume when the engine is revved

several times.

Standard value: Momentarily 20 cm

3

/sec. (2.5 SCFH) or

more.

AKX00340

INTAKE MANIFOLD

THROTTLE BODY

TO COMBUSTION
CHAMBER

FROM
AIR
CLEANER

OFF

ON

EVAP PURGE SOLENOID
(ON: OPENED)

PURGE
FLOW
INDICATOR
(MB995061)

PURGE HOSE

EVAP CANISTER

AB

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

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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 evaporative emission
purge solenoid. If the purge flow volume is at the standard
value, replace the EVAP canister.

EVAPORATIVE EMISSION PURGE SOLENOID
CHECK

M1173001700159

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

mark) from the EVAP purge solenoid valve.
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 (B) of the EVAP

purge solenoid valve (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.

5. Measure the resistance between the terminals of the EVAP

purge solenoid valve.

Standard value: 30

− 34 Ω [at 20°C (68°F)]

6. Replace solenoid if resistance is out of specification.

VOLUME AIRFLOW SENSOR CHECK

M1173007900430

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code Chart

P.13Ab-22

.

BAROMETRIC PRESSURE SENSOR CHECK

M1173008000214

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code Chart

P.13Ab-22

.

BATTERY POSITIVE
VOLTAGE

NORMAL CONDITION

Applied

Vacuum leaks

Not applied

Vacuum maintained

AKX00341

A

B

AKX00341AC

AKX00342