2016 JEEP GRAND CHEROKEE catalytic converter

Yellow Telltale Indicator Lights
Engine Check/Malfunction Indicator Light (MIL)
Yellow TelltaleLight What It Means
Engine Check/Malfunction Indicator Light (MIL)
The Engine Check/Malfunction Indicator Light (MIL) is a part of an Onboard Diagnostic
System called OBD II that monitors engine and automatic transmission control systems. The
light will illuminate when the ignition is in the ON position before engine start. If the bulb
does not come on when turning the key from OFF to ON/RUN, have the condition checked
promptly.
Certain conditions, such as a loose or missing gas cap, poor quality fuel, etc., may illuminate
the light after engine start. The vehicle should be serviced if the light stays on through sev-
eral typical driving styles. In most situations, the vehicle will drive normally and will not
require towing.
When the engine is running, the MIL may flash to alert serious conditions that could lead to
immediate loss of power or severe catalytic converter damage. The vehicle should be ser-
viced as soon as possible if this occurs.4
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CAUTION!
Prolonged driving with the Malfunction Indicator
Light (MIL) on could cause damage to the engine
control system. It also could affect fuel economy and
driveability. If the MIL is flashing, severe catalytic
converter damage and power loss will soon occur.
Immediate service is required.
WARNING!
A malfunctioning catalytic converter, as referenced
above, can reach higher temperatures than in normal
operating conditions. This can cause a fire if you
drive slowly or park over flammable substances such
as dry plants, wood, cardboard, etc. This could result
in death or serious injury to the driver, occupants or
others.
306 UNDERSTANDING YOUR INSTRUMENT PANEL

WARNING!(Continued)
•Do not attempt to push or tow your vehicle to get it
started. Vehicles equipped with an automatic trans-
mission cannot be started this way. Unburned fuel
could enter the catalytic converter and once the
engine has started, ignite and damage the converter
and vehicle.
• If the vehicle has a discharged battery, booster
cables may be used to obtain a start from a booster
battery or the battery in another vehicle. This type
of start can be dangerous if done improperly. Refer
to “Jump-Starting” in “What To Do In Emergen-
cies” for further information.
Clearing A Flooded Engine (Using ENGINE
START/STOP Button)
If the engine fails to start after you have followed the
“Normal Starting” or “Extreme Cold Weather proce-
dures, it may be flooded. To clear any excess fuel:
1. Press and hold the brake pedal.
2. Press the accelerator pedal all the way to the floor and hold it.
3. Push and release the ENGINE START/STOP button once.
The starter motor will engage automatically, run for 10
seconds, and then disengage. Once this occurs, release
the accelerator pedal and the brake pedal, wait 10 to 15
seconds, then repeat the “Normal Starting” procedure.
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Indiscriminate use of fuel system cleaning agents should
be avoided. Many of these materials intended for gum
and varnish removal may contain active solvents or
similar ingredients. These can harm fuel system gasket
and diaphragm materials.
Fuel System Cautions
CAUTION!
Follow these guidelines to maintain your vehicle’s
performance:
•The use of leaded gasoline is prohibited by Federal
law. Using leaded gasoline can impair engine per-
formance and damage the emissions control
system.
• An out-of-tune engine or certain fuel or ignition
malfunctions can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
(Continued)
CAUTION! (Continued)
some light smoke, your engine may be out of tune
or malfunctioning and may require immediate ser-
vice. Contact your authorized dealer for service
assistance.
• The use of fuel additives, which are now being
sold as octane enhancers, is not recommended.
Most of these products contain high concentrations
of methanol. Fuel system damage or vehicle perfor-
mance problems resulting from the use of such
fuels or additives is not the responsibility of the
manufacturer and may void or not be covered
under the New Vehicle Limited Warranty.
NOTE: Intentional tampering with the emissions control
system can result in civil penalties being assessed against
you.
558 STARTING AND OPERATING

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 emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the “Malfunction Indicator Light (MIL).” It
will also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though 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 control 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 damage and power loss
will soon occur. Immediate service is required.
Onboard Diagnostic System (OBD II)
Cybersecurity
Your vehicle is required to have an Onboard Diagnostic
system (OBD II) and a connection port to allow access to
information related to the performance of your emissions
controls. Authorized service technicians may need to
610 MAINTAINING YOUR VEHICLE

CAUTION!
•The catalytic converter requires the use of un-
leaded fuel only. Leaded gasoline will destroy the
effectiveness of the catalyst as an emissions control
device and may seriously reduce engine perfor-
mance and cause serious damage to the engine.
• Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition.
In the event of engine malfunction, particularly
involving engine misfire or other apparent loss of
performance, have your vehicle serviced promptly.
Continued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and
vehicle. Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
NOTE:
Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
638 MAINTAINING YOUR VEHICLE

In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe
and abnormal catalyst overheating. If this occurs, stop
the vehicle, turn off the engine and allow it to cool.
Service, including a tune-up to manufacturer’s specifica-
tions, should be obtained immediately.
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, or for prolonged periods during very rough
idle or malfunctioning operating conditions.Cooling System
WARNING!
• When working near the radiator cooling fan, dis-
connect the fan motor lead or turn the ignition
switch to the OFF position. The fan is temperature
controlled and can start at any time the ignition
switch is in the ON position.
• You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had
time to cool. Never try to open a cooling system
pressure cap when the radiator is hot.
Coolant Checks
Check the engine coolant (antifreeze) protection every 12
months (before the onset of freezing weather, where
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