Jeep Grand Cherokee 2015, Operating Information Manual

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ONBOARD DIAGNOSTIC
SYSTEM — OBD II
Your vehicle is equipped with a sophisticated
onboard diagnostic system called OBD II. This
system monitors the performance of the emis-
sions, engine, and automatic transmission con-
trol systems. When these systems are operat-
ing properly, your vehicle will provide excellent
performance and fuel economy, as well as
engine emissions well within current govern-
ment regulations.
If any of these systems require service, the
OBD II system will turn on the “Malfunction
Indicator Light (MIL).” It will also store diagnos-
tic codes and other information to assist your
service technician in making repairs. Although
your vehicle will usually be drivable and not
need towing, see your authorized dealer for
service as soon as possible.
CAUTION!
•
Prolonged driving with the MIL on could
cause further damage to the emission con-
trol system. It could also affect fuel
economy and driveability. The vehicle
must be serviced before any emissions
tests can be performed.
•
If the MIL is flashing while the engine is
running, severe catalytic converter dam-
age and power loss will soon occur. Imme-
diate service is required.
Loose Fuel Filler Cap Message
If the vehicle diagnostic system determines that
the fuel filler cap is loose, improperly installed,
or damaged, a “CHECK GASCAP” message
will be displayed in the Electronic Vehicle Infor-
mation Center (EVIC) or Driver Information Dis-
play (DID). Refer to “Electronic Vehicle Informa-
tion (EVIC) or
" Driver Information Display (DID)”
in “Understanding Your Instrument Panel” for
further information. Tighten the fuel filler cap
until a “clicking” sound is heard. This is an
indication that the fuel filler cap is properly
tightened. Refer to “Onboard Diagnostic Sys-
tem” in “Maintaining Your Vehicle” for further
information.
EMISSIONS INSPECTION AND
MAINTENANCE PROGRAMS
In some localities, it may be a legal requirement
to pass an inspection of your vehicle’s emis-
sions control system. Failure to pass could
prevent vehicle registration.
Normally, the OBD II system will be
ready. The OBD II system may
not be
ready if your vehicle was recently
serviced, recently had a dead battery
or a battery replacement. If the OBD II system
should be determined not ready for the I/M test,
your vehicle may fail the test.
Your vehicle has a simple ignition actuated test,
which you can use prior to going to the test
station. To check if your vehicle’s OBD II system
is ready, you must do the following:
1. Cycle the ignition switch to the ON position,
but do not crank or start the engine.
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