Crankcase Emission Control System; Fuel Filter - Jeep 2004 Grand Cherokee Owner's Manual

To minimize the possibility of catalytic converter dam-
age:
• Do not shut off the engine or interrupt the ignition
when the transmission is in gear and the vehicle is in
motion.
• Do not try to start the engine by pushing or towing the
vehicle.
• Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing.
• Do not idle the engine for prolonged periods during
very rough idle or malfunctioning operating condi-
tions.
• Do not allow vehicle to run out of fuel.
MAINTAINING YOUR VEHICLE 263
NOTE: Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.

Crankcase Emission Control System

Proper operation of this system depends on freedom
from sticking or plugging due to deposits. As vehicle
mileage builds up, the PCV valve and passages may
accumulate deposits. If a valve is not working properly,
replace it with a new valve. DO NOT ATTEMPT TO
CLEAN THE OLD PCV VALVE!
Check ventilation hose for indication of damage or
plugging deposits. Replace if necessary.

Fuel Filter

A plugged fuel filter can cause hard starting or limit the
speed at which a vehicle can be driven. Should an
excessive amount of dirt accumulate in the fuel tank,
frequent replacement of the fuel filter which is mounted
in the fuel tank may be necessary.
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