Jeep Grand Cherokee 4x2 2019 Supplement Manual page 36

34 STARTING AND OPERATING
System Overview
This vehicle is equipped with a Diesel Exhaust Fluid (DEF)
injection system and a Selective Catalytic Reduction (SCR)
catalyst to meet the emission requirements.
The DEF injection system consists of the following compo-
nents:
• DEF tank
• DEF pump
• DEF injector
• Electronically-heated DEF Lines
• NOx sensors
• Temperature sensors
• SCR catalyst
The DEF injection system and SCR catalyst enable the
achievement of diesel emissions requirements; while main-
taining outstanding fuel economy, drivability, torque and
power ratings.
Refer to "Instrument Cluster Display" in "Getting To Know
Your Instrument Panel" for system messages and warnings.
NOTE:
• Your vehicle is equipped with a DEF injection system. You
may occasionally hear an audible clicking noise from
under the vehicle at a stop. This is normal operation.
• The DEF pump will run for a period of time after engine
shutdown to purge the DEF system. This is normal
operation and may be audible from the rear of the
vehicle.
Diesel Exhaust Fluid Storage
Diesel Exhaust Fluid (DEF) is considered a very stable
product with a long shelf life. If DEF is kept in tempera-
tures between 10° and 90°F (-12° and 32°C), it will last a
minimum of one year.
DEF is subject to freezing at the lowest temperatures.
For example, DEF may freeze at temperatures at or below
12° F (-11° C). The system has been designed to operate in
this environment.