2021 JEEP WRANGLER UNLIMITED check engine

211
Once A Month Or Before A Long Trip
Check the engine oil level about five
minutes after a fully warmed engine is
shut off. Checking the oil level while the
vehicle is on level ground will improve the
accuracy of the oil level reading. Add oil
only when the level is at or below the ADD
or MIN mark.
Check the windshield washer solvent and
add if required.
Check tire pressure and look for unusual
wear or damage. Rotate tires at the first
sign of irregular wear.
Inspect the battery and clean and tighten
the terminals as required.
Check the fluid levels of coolant reservoir,
brake master cylinder and power steering
and fill as needed.
Check all lights and other electrical items
for correct operation.At Each Oil Change
Change the engine oil filter.
Inspect the brake hoses and lines.
Inspect the CV/Universal joints.
Check tire pressure and look for unusual
wear or damage. Rotate tires at the first
sign of irregular wear, even if it occurs
before the oil indicator system turns on.
Required Maintenance Intervals
Refer to the Maintenance Plan on the
following pages for the required maintenance
intervals.
Maintenance Plan
NOTE:
Once you have carried out the last interven -
tion in the table, continue with the sched -
uled servicing, maintaining the frequency
indicated in the plan by marking each oper -
ation with a dot or dedicated note. Simply
restarting the maintenance from the start of
the plan may cause the allowed interval to be
exceeded for some operations.
CAUTION!
Failure to perform the required
maintenance items may result in damage
to the vehicle.
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217
Once A Month Or Before A Long Trip
Check engine oil level.
Check windshield washer fluid level.
Check tire pressure and look for unusual
wear or damage. Rotate tires at the first
sign of irregular wear, even if it occurs
before the oil indicator system turns on.

Check the fluid levels of the coolant reservoir
and brake master cylinder, fill as needed.

Check function of all interior and exterior lights.Demanding Vehicle Use
Restore additive level for AdBlue® Diesel
emissions (UREA) (if equipped), when the
lamp is illuminated or the message on the
instrument panel.
Maintenance Plan — Diesel Engine
Required Maintenance Intervals
Refer to the maintenance plan on the
following pages for the required maintenance
intervals.
NOTE:
Once you have carried out the last intervention in the table, continue with the scheduled servicing, maintaining the frequency indicated in
the plan by marking each operation with a dot or dedicated note. Simply restarting the maintenance from the start of the plan may cause the
allowed interval to be exceeded for some operations.
CAUTION!

Failure to perform the required maintenance
items may result in damage to the vehicle.

At Every Oil Change Interval As Indicated By Oil Change Indicator System:
Change oil and filter
Rotate the tires. Rotate at the first sign of irregular wear, even if it occurs before the oil indicator system turns on
Inspect battery and clean and tighten terminals as required
Inspect the CV/Universal joints
Inspect brake pads, shoes, rotors, drums, hoses and park brake
Inspect engine cooling system protection and hoses
Inspect exhaust system
Inspect engine air cleaner if using in dusty or off-road conditions
Inspect all door latches for presence of grease, reapply if necessary.
Inspect coolant level.
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SERVICING AND MAINTENANCE
218Mileage or time passed (whichever comes first)
12,500
25,000
37,500
50,000
62,500
75,000
87,500
100,000
112,500
125,000
137,500
150,000
162,500
175,000
187,500
Or Years: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Or Kilometers:
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
200,000
220,000
240,000
260,000
280,000
300,000
Additional Inspections
Change the engine oil and engine oil filter. (*)
Inspect the CV/Universal joints. X X X X X X X X X X X X X X X
Inspect front suspension, rear suspension, boot seals,
tie rod ends, and replace if necessary. X X X X X X X
Visually inspect condition of: exterior bodywork,
underbody protection, pipes and hoses (exhaust - fuel
system - brakes), rubber elements (boots, sleeves,
bushings, etc.). X X X X X X X
If using your vehicle in dusty or off-road conditions,
inspect the air cleaner filter, and replace if necessary. X X X X X X X X X X X X X X X
Inspect the brake linings, parking brake function. X X X X X X X
Check and, if necessary, top up fluid levels. (°) X X X X X X X X X X X X X X X
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SERVICING AND MAINTENANCE
224
(Continued)
Checking Oil Level — Gasoline Engine
To ensure proper lubrication of your vehicle's
engine, the engine oil must be maintained at
the correct level. The engine oil level should
be checked five minutes after a warmed up
engine has been shut off.
Checking the oil while the vehicle is on level
ground will improve the accuracy of the oil
level readings. Always maintain the oil level
within the SAFE zone on the dipstick. Adding
1 quart (0.95 liters) of oil when the reading
is at the bottom of the crosshatch zone will
result in a reading at the top of the cross-
hatch zone on these engines.
Adding Washer Fluid
The fluid reservoir for the windshield
washers and the rear window washer (if
equipped) is shared. The fluid reservoir is
located in the engine compartment. Be sure
to check the fluid level at regular intervals.
Fill the reservoir with windshield washer
solvent only (not radiator antifreeze). When
refilling the washer fluid reservoir, take some
washer fluid and apply it to a cloth or towel
and wipe clean the wiper blades; this will
help blade performance.
To prevent freeze-up of your windshield
washer system in cold weather, select a solu -
tion or mixture that meets or exceeds the
temperature range of your climate. This
rating information can be found on most
washer fluid containers. WARNING!

Never smoke while working in the engine
compartment: gas and inflammable vapors
may be present, with the risk of fire.

Be very careful when working in the
engine compartment when the engine is
hot: you may get burned. Do not get too
close to the radiator cooling fan: the
electric fan may start; danger of injury.
Scarves, ties and other loose clothing
might be pulled by moving parts.
CAUTION!
Be careful not to confuse the various
types of fluids while topping up: they are
not compatible with each other! Topping
up with an unsuitable fluid could
severely damage your car.
The oil level must never exceed the MAX
mark.
Always top up using engine oil of the
same specifications as that already in
the engine.
If the engine oil is being topped up, wait
for the engine to cool down before loos-
ening the filler cap, particularly for vehi -
cles with aluminium cap (if equipped).
WARNING: risk of burns!
Overfilling or underfilling the crankcase
will cause aeration or loss of oil pressure.
This could damage your engine.
CAUTION! (Continued)
WARNING!
Commercial windshield washer solvents
are flammable. They could ignite and burn
you. Care must be exercised when filling or
working around the washer solution.
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SERVICING AND MAINTENANCE
230(Continued)
Coolant Checks
Check the engine and, intercooler (if
equipped) coolant (antifreeze) protection
every 12 months (before the onset of
freezing weather, where applicable). If the
engine and, intercooler (if equipped) is dirty
or rusty in appearance, the system should be
drained, flushed and refilled with fresh OAT
coolant (conforming to MS.90032) by an
authorized dealer. Check the front of the A/C
condenser (if equipped) or radiator for any
accumulation of bugs, leaves, etc. If dirty,
clean by gently spraying water from a garden
hose vertically down the face of the A/C
condenser (if equipped) or the back of the
radiator core.Check the engine and, intercooler (if
equipped) cooling system hoses for brittle
rubber, cracking, tears, cuts, and tightness
of the connection at the coolant recovery
bottle and radiator. Inspect the entire system
for leaks. DO NOT REMOVE THE COOLANT
PRESSURE CAP WHEN THE COOLING
SYSTEM IS HOT.
Brake System
In order to ensure brake system perfor
-
mance, all brake system components should
be inspected periodically. Refer to the
“Maintenance Plan” in this section for the
proper maintenance intervals.
Fluid Level Check — Brake Master Cylinder
The fluid level of the master cylinder should
be checked whenever the vehicle is serviced,
or immediately if the brake system warning
light is on. If necessary, add fluid to bring
level within the designated marks on the side
of the reservoir of the brake master cylinder.
Be sure to clean the top of the master
cylinder area before removing cap. With disc
brakes, fluid level can be expected to fall as
the brake pads wear. Brake fluid level should
be checked when pads are replaced. If the
brake fluid is abnormally low, check the
system for leaks.
Refer to “Fluids And Lubricants” in “Tech -
nical Specifications” for further information.When working near the radiator cooling
fan, turn the ignition to the OFF mode.
The fan is temperature controlled and
can start at any time the ignition is in the
ON mode.
WARNING! (Continued)
WARNING!
Riding the brakes can lead to brake failure
and possibly a collision. Driving with your
foot resting or riding on the brake pedal
can result in abnormally high brake
temperatures, excessive lining wear, and
possible brake damage. You would not
have your full braking capacity in an
emergency. WARNING!
Use only manufacturer's recommended
brake fluid. Refer to “Fluids And Lubri -
cants” in “Technical Specifications” for
further information. Using the wrong
type of brake fluid can severely damage
your brake system and/or impair its
performance. The proper type of brake
fluid for your vehicle is also identified on
the original factory installed hydraulic
master cylinder reservoir.
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TECHNICAL SPECIFICATIONS
248
Tighten the lug nuts/bolts in a star pattern
until each nut/bolt has been tightened twice.
Ensure that the socket is fully engaged on
the lug nut/bolt (do not insert it halfway).Torque Patterns
After 25 miles (40 km), check the lug nut/
bolt torque to be sure that all the lug nuts/
bolts are properly seated against the wheel.WHEELS
Refer to the tire placard label located on the
door sill of the vehicle or to the Registration
Document for the tire size and pressure.
Refer to “Tires” in “Servicing And Mainte -
nance” chapter for further information.
WEIGHTS
For further information refer to “Vehicle
Loading” in the “Starting And Operating”
chapter.
FUEL REQUIREMENTS —
GASOLINE ENGINE
2.0L Engine
This engine is designed to meet all emission
regulations, and provide satisfactory fuel
economy and performance when using
high-quality unleaded gasoline with a recom -
mended RON of 95.
While operating on gasoline with the
required octane number, hearing a light
knocking sound from the engine is not a
cause for concern. However, if the engine is
heard making a heavy knocking sound, see
your dealer immediately. Use of gasoline
with a lower than recommended octane
number can cause engine failure and may
void or not be covered by the New Vehicle
Limited Warranty.
Poor quality gasoline can cause problems
such as hard starting, stalling, and hesita -
tions. If you experience these symptoms, try
another brand of gasoline before considering
service for the vehicle.
WARNING!
To avoid the risk of forcing the vehicle off
the jack, do not tighten the lug nuts/bolts
fully until the vehicle has been lowered.
Failure to follow this warning may result in
personal injury.
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249
3.6L Engine
This engine is designed to meet all emissions
regulations and provide excellent fuel
economy and performance when using
high-quality unleaded gasoline with a
minimum Research Octane Number (RON)
of 91.
Light spark knock at low engine speeds is not
harmful to your engine. However, continued
heavy spark knock at high speeds can cause
damage, and immediate service is required.
Poor quality gasoline can cause problems
such as hard starting, stalling, and hesita-
tions. If you experience these symptoms, try
another brand of gasoline before considering
service for the vehicle. Besides using unleaded gasoline with the
proper octane rating, gasolines that contain
detergents, corrosion and stability additives
are recommended. Using gasolines that have
these additives may help improve fuel
economy, reduce emissions, and maintain
vehicle performance.
Poor quality gasoline can cause problems
such as hard starting, stalling, and hesita
-
tions. If you experience these symptoms, try
another brand of gasoline before considering
service for the vehicle.
Materials Added To Fuel
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 Icon Identification Compliant To
EN16942
The following symbols make it easier to
recognize the correct type of fuel to be used
on your vehicle. Before proceeding with the
supply, check the symbols placed inside the
fuel filler flap (if present) and compare them
with the symbol on the fuel pump (if
present).
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251
FUEL REQUIREMENTS —
DIESEL ENGINE
Use good quality diesel fuel from a reputable
supplier. If the outside temperature is very
low, the diesel fuel thickens due to the
formation of paraffin clots with consequent
defective operation of the fuel supply
system.
In order to avoid these problems different
types of fuel are distributed according to the
season: summer type, winter type and arctic
type (cold/mountain areas). If fueling with
diesel fuel whose features are not suitable
for the temperature of use, it is advisable to
mix in a suitable additive with the fuel. With
the proportions shown on the container, pour
the additive in the tank before fueling.
When using or parking the vehicle for a long
time in the mountains or cold areas, it is
advisable to refuel using locally available
fuel. In this case, it is also advisable to keep
the tank over half full.
This vehicle must only use premium diesel
fuel that meets the requirements of EN 590.
Biodiesel blends up to 7% that meet EN
590 may also be used.Diesel fuel is seldom completely free of
water. To prevent fuel system trouble, drain
the accumulated water from the fuel/water
separator using the provided fuel/water
separator drain. If you buy good quality fuel
and follow the cold weather advice above,
fuel conditioners should not be required in
your vehicle. If available in your area, a high
cetane “premium” diesel fuel may offer
improved cold-starting and warm-up perfor
-
mance.
Fuel Icon Identification Compliant To
EN16942
The following symbols make it easier to
recognize the correct type of fuel to be used
on your vehicle. Before proceeding with the
supply, check the symbols placed inside the
fuel filler flap (if present) and compare them
with the symbol on the fuel pump (if
present).
WARNING!
Do not use alcohol or gasoline as a
fuel-blending agent. They can be unstable
under certain conditions and hazardous or
explosive when mixed with diesel fuel.
CAUTION!
The manufacturer requires that you must
fuel this vehicle with Ultra Low Sulfur
Highway Diesel fuel (15 ppm Sulfur
maximum) and prohibits the use of Low
Sulfur Highway Diesel fuel.
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