Mitsubishi Montero (2002-2004). Manual - part 849
EMISSION CONTROL
TSB Revision
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