check engine JEEP WRANGLER UNLIMITED 2021 Owner handbook (in English)

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.
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 230

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.
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 248

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).
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 249

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.
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 251

277
Apps — If Equipped
To access Apps, press the Uconnect Apps
button on the touchscreen to browse the list
of applications:
EcoDrive
MyCar
TuneIn
Deezer
Reuters
Twitter
Facebook Check-In
Apple CarPlay®
Android Auto™
TomTom® Live Services, and many more.
UCONNECT SETTINGS
The Uconnect system allows you to access
Customer Programmable feature settings
such as Language, Display, Units, Voice,
Clock, Camera, Safety & Driving Assistance,
Mirrors & Wipers, Lights, Doors & Locks,
Auto-On Comfort, AUX Switches, Engine Off
Options, Audio, Phone/Bluetooth®, Radio
Setup, Restore Settings, and System Infor-
mation through buttons on the touchscreen.
Push the SETTINGS button (Uconnect 3), or
press the Apps button (Uconnect 4/4 NAV)
located near the bottom of the touchscreen,
then press the Settings button on the touch -
screen to access the Settings screen. When
making a selection, scroll up or down until
the preferred setting is highlighted, then
press the preferred setting until a
check-mark appears next to the setting,
showing that setting has been selected.
NOTE:
Depending on the vehicle’s options, feature
settings may vary.
Refer to “Uconnect Settings” in “Multi -
media” in your Owner’s Manual for further
information.
OFF-ROAD PAGES — IF
EQUIPPED

Your vehicle is equipped with Off-Road Pages,
which provides the vehicle status while oper -
ating on off-road conditions. It supplies infor -
mation relating to the vehicle ride height, the
status of the transfer case, the pitch and roll of
the vehicle (if equipped).

To access Off-Road Pages, press the Apps
button on the touchscreen, and then select
“Off-Road Pages”.
Main Menu
1 — Off-Road Pages App
2 — Uconnect Apps Button
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 277

319
INDEX
A
Accessories ....................................... 258Mopar ........................................... 258
Active Speed Limiter .......................... 156
Adaptive Cruise Control (ACC)
(Cruise Control) ................................. 158
Adding Fuel ...................................... 169
Additives, Fuel .................................. 249
Air Bag Air Bag Operation ........................... 107Air Bag Warning Light ..................... 105
Disable, Passenger Air Bag.............. 107

Enhanced Accident Response ... 115 , 209

Event Data Recorder (EDR) ............. 209
Front Air Bag ................................. 106
If Deployment Occurs ..................... 114
Knee Impact Bolsters ..................... 112
Maintaining Your Air Bag System ..... 116
Maintenance .................................. 116
Redundant Air Bag Warning Light .... 105
Transporting Pets ........................... 134
Air Bag Light ........................65 , 105 , 136
Air Conditioning................................... 44
Air Conditioning Filter .......................... 46
Air Conditioning System ....................... 44
Air Conditioning, Operating Tips ............ 45 Air Pressure
Tires ............................................. 233
Alarm Arm The System .............................. 15
Disarm The System .......................... 15
Security Alarm ............................15 , 68
Alarm (Security Alarm) ......................... 16
Alterations/Modifications Vehicle ............................................. 2
Android Auto...................... 266 , 271 , 302
Apps ............................................. 274
Communication ............................. 273
Maps ............................................ 272
Music ........................................... 273
Antifreeze (Engine Coolant) ................ 253
Anti-Lock Brake System (ABS) .............. 78
Anti-Lock Warning Light ....................... 68
Apple CarPlay .................... 267 , 274 , 303
Apps ............................................. 276
Maps ............................................ 276
Messages ...................................... 275
Music ........................................... 275
Phone ........................................... 275
Assist, Hill Start .................................. 85
Audio Systems (Radio) ................260 , 262
Auto Down Power Windows ................... 46
Automatic Headlights .......................... 33 Automatic High Beams .........................33
Automatic Temperature Control (ATC) ....44
Automatic Transmission......................145
Fluid Level Check ................... 231 , 232
Fluid Type ............................. 231 , 257
Special Additives ............................231

Auxiliary Electrical Outlet (Power Outlet)... 56

Auxiliary Power Outlet ..........................56
Auxiliary Switches ................................58
Axle Fluid..........................................257
Axle Lock ..........................................151
B
Battery ........................................ 66 , 225
Charging System Light ......................66
Belts, Seat ........................................136
Blind Spot Monitoring ..........................87
Brake Assist System .............................79
Brake Control System ...........................79
Brake Fluid ............................... 230 , 257
Brake System ....................................230 Fluid Check ...................................230
Master Cylinder ..............................230
Warning Light...................................65
Brake/Transmission Interlock...............144
Bulb Replacement ..................... 179 , 181
Bulbs, Light .............................. 137 , 179
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 319

320
INDEX
C
Camera, Rear .................................... 167
Capacities, Fluid................................ 253
Caps, FillerFuel ...................................... 169 , 170
Oil (Engine) ................................... 221
Car Washes ....................................... 243
Carbon Monoxide Warning .................. 135
Center High Mounted Stop Light ......... 183
Certification Label ............................. 174
Chains, Tire ...................................... 240
Change Oil Indicator ............................ 61
Changing A Flat Tire .......................... 232
Checking Your Vehicle For Safety ........ 135
Checks, Safety .................................. 135
Cleaning Wheels .......................................... 239
Climate Control Automatic........................................ 37
Clock Settings ................................... 261
Compact Spare Tire ........................... 238
Connector UCI ............................................... 280
Universal Consumer Interface (UCI) ........................... 280
Cooling System .................................. 229 Cooling Capacity ............................ 253Inspection ..................................... 230
Selection Of Coolant (Antifreeze) ........................ 253 , 254 Cruise Control (Speed Control) ............ 158
Cruise Light ...................................74
, 76
Customer Assistance .......................... 304
Cybersecurity .................................... 260
D
Daytime Running Lights ....................... 32
Dealer Service ................................... 226
Defroster, Windshield......................... 136
Delay (Intermittent) Wipers .................. 35
Diagnostic System, Onboard ................. 77
Diesel Display Messages ............................. 62
Dimmer Switch Headlight ........................................ 32
Dipsticks Oil (Engine) ................................... 224
Disabled Vehicle Towing .................... 207
Do Not Disturb ...........................292 , 301
Door Ajar .......................................66 , 68
Door Ajar Light ...............................66 , 68
Doors ................................................. 18 Removal.....................................21 , 23
Removal, Front ................................ 21
Removal, Rear ................................. 23
Drag And Drop Menu ..................264 , 269
Driver’s Seat Back Tilt ......................... 24
Dual Top .......................................47 , 53 E
Electric Brake Control System ...............79
Anti-Lock Brake System ....................78
Electronic Roll Mitigation ............ 80 , 87

Electrical Outlet, Auxiliary (Power Outlet) .. 56

Electrical Power Outlets ........................56
Electronic Speed Control
(Cruise Control) ..................................157
Electronic Stability Control (ESC) ..........80
Electronic Throttle Control Warning
Light ...................................................66
Emergency, In Case Of Jacking .................................. 192 , 232
Jump Starting ................................201
Emissions..........................................258
Engine ..............................................221 Break-In Recommendations .............143Compartment ................. 221 , 222 , 223
Compartment Identification .............. 221 , 222 , 223
Coolant (Antifreeze) ........................254
Cooling ..........................................229 Exhaust Gas Caution .......................135
Fuel Requirements ................. 248 , 253
Jump Starting ................................201
Oil ........................................ 253 , 254
Oil Filler Cap ..................................221
Oil Selection ..................................253
Overheating....................................204
Starting .........................................138
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 320

321
Enhanced Accident Response
Feature ..................................... 115, 209
Exhaust Gas Caution .......................... 135
Exhaust System ......................... 135 , 228
Exterior Lights ............................. 32 , 137
F
Fabric Care ....................................... 244
Fabric Top ........................................ 244
Filters Air Conditioning ............................... 46
Engine Oil ..................................... 254
Flashers Hazard Warning ............................. 179Turn Signal.................................... 137
Turn Signals .....................74 , 181 , 182
Flash-To-Pass ...................................... 33
Flat Tire Changing ..................... 232 , 237
Flat Tire Stowage ....................... 232 , 237
Fluid Capacities................................. 253
Fluid Leaks ....................................... 137
Fluid Level Checks Brake ............................................ 230
Engine Oil ..................................... 224
Fluid, Brake ...................................... 257
Fluids And Lubricants ........................ 254
Fog Lights ..............................33 , 72 , 182
Fog Lights, Rear .................................. 33 Fog Lights, Service ............................ 182
Fold And Tumble Rear Seat .................. 27
Fold-Flat Seats .................................... 24
Folding Rear Seats .............................. 26
Forward Collision Warning .................... 89
Four Wheel Drive ............................... 146
Operation ...................................... 146
Shifting......................................... 146
System ......................................... 146
Four Wheel Drive Operation ................ 148
Four-Way Hazard Flasher.................... 179
Freedom Panels .................................. 51
Freeing A Stuck Vehicle ..................... 206
Fuel ................................................. 248 Adding .......................................... 169
Additives ....................................... 249
Consumption ................................. 258
Filler Cap (Gas Cap) ................169 , 170
Gasoline........................................ 248
Materials Added............................. 249
Octane Rating.........................248 , 254
Requirements ................................ 253
Specifications................................ 254
Tank Capacity................................ 253
Fueling ............................................. 169
Fuses ............................................... 183 G
Gas Cap (Fuel Filler Cap) ............ 169
, 170
Gasoline Particulate Filter (GPF)............59
Gasoline, (Fuel) .................................248
Glass Cleaning ...................................246
GVWR ...............................................174
H
Hard Top .............................................51
Hazard Warning Flashers ....................179
Head Restraints ...................................28
Headlights Automatic ........................................33
Bulb Replacement ..........................181
Cleaning ........................................242
High Beam/Low Beam Select Switch .........................................32
Leveling...........................................34 Lights On Reminder ..........................34
Passing............................................33Replacing ......................................181
Heated Steering Wheel .........................31
High Beam/Low Beam Select
(Dimmer) Switch ..................................32
Hill Descent Control .............................83
Hill Descent Control Indicator ...............83
Hill Start Assist....................................85
Hood Prop ...........................................55
Hood Release ......................................55
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 321

322
INDEX
I
Ignition ............................................... 12Switch ............................................ 12
Installation.......................................... 51
Installing ............................................ 53
Instrument Cluster ............................... 61 Descriptions .................................... 74
Display ............................................ 60
Menu Items ..................................... 61
Instrument Panel Lens Cleaning .......... 246
Integrated Power Module (Fuses)......... 184
Interior Appearance Care .................... 245
Intermittent Wipers (Delay Wipers) ........ 35
Introduction .......................................... 1
Inverter Power.............................................. 57
J
Jack Location .................................... 193
Jack Operation .......................... 195 , 232
Jacking Instructions ........................... 195
Jump Starting ................................... 201 K
Key Fob
Arm The System .............................. 15
Disarm The System .......................... 15
Keyless Enter-N-Go.............................. 18 Passive Entry ................................... 18
Keys................................................... 11 Replacement ................................... 12
L
Lap/Shoulder Belts ............................ 100
Latches ............................................ 137 Hood .............................................. 55
Leaks, Fluid ...................................... 137
Leveling Headlights....................................... 34
Life Of Tires...................................... 235
Light Bulbs ................................137 , 179
Lights............................................... 137 Air Bag ............................ 65 , 105 , 136
Automatic Headlights ....................... 33
Brake Assist Warning........................ 82
Brake Warning ................................. 65
Bulb Replacement ..................179 , 181
Center Mounted Stop ..................... 183 Cruise ........................................74 , 76 Daytime Running ..............................32
Dimmer Switch, Headlight.................32
Electronic Stability Program (ESP)
Indicator ......................................67
Engine Temperature Warning .............67 Exterior.................................... 32 , 137
Fog ......................................... 72 , 182
Hazard Warning Flasher ..................179
Headlight Leveling ............................34
Headlights .....................................181
High Beam.......................................32
High Beam/Low Beam Select .............32 Hill Descent Control Indicator ............83Lights On Reminder ..........................34
Malfunction Indicator (Check Engine) .............................69
Park ................................................74
Passing............................................33 Rear Servicing ................................182
Rear Tail Lamps .............................182
Seat Belt Reminder .............. 67 , 74 , 75
Security Alarm .................................68
Service .................................. 179 , 181
Side Marker ...................................182
Tire Pressure Monitoring (TPMS) ........92
Traction Control................................82
Turn Signal ....................................137
Turn Signals..................... 74 , 181 , 182
Warning Instrument Cluster Descriptions ........................... 67 , 74
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 322

323
Loading Vehicle ................................. 174
LockingAxle .............................................. 151
Locks Child Protection ............................... 20
Low Tire Pressure System ..................... 92
Lowering ............................................. 47
Lowering Four Door .............................. 47
Lowering The Top ................................ 47
Lowering Two Door ............................... 47
Lug Nuts/Bolts .................................. 247
Luggage Carrier ................................... 58
M
Maintenance ....................................... 53
Maintenance Free Battery ................... 225
Maintenance Schedule ............... 210 , 216
Malfunction Indicator
Light (Check Engine)............................ 69
Manual Park Release.................................. 204
Modifications/Alterations Vehicle .............................................. 2
Monitor, Tire Pressure System ............... 92
Mopar Accessories ............................. 258
N
Navigation ........................................ 282
New Vehicle Break-In Period ............... 143 O
Occupant Restraints ............................ 97
Octane Rating, Gasoline
(Fuel) ................................ 248
, 249 , 254
Off Road Pages ................................. 277 Accessory Gauges .......................... 279
Drivetrain ...................................... 278
Pitch And Roll ............................... 279
Status Bar ..................................... 278
Oil Pressure Light ................................ 67
Oil, Engine ....................................... 254 Capacity........................................ 253
Dipstick ........................................ 224
Filter ............................................ 254
Pressure Warning Light..................... 67Recommendation ........................... 253
Viscosity ....................................... 253
Onboard Diagnostic System .................. 77
Operating Precautions .......................... 77
Overheating, Engine........................... 204
P
Paddle Shifters ................................. 145
ParkSense System, Rear .................... 161
Passenger Airbag Disable ................... 107
Passive Entry ...................................... 18
Personalized Main Menu .................... 264
Pets ................................................. 134
Phone (Uconnect).............................. 285 Pairing .......................................... 287 Phonebook ........................................291
Power
Inverter............................................57Windows ..........................................46
Power Sliding Top ................................53 Operation.........................................53
Pinch Protect ...................................53
Power Steering Fluid ..........................257
Pregnant Women And Seat Belts .........104
Preparation For Jacking ......................194
Pretensioners Seat Belts ......................................104
R
Radial Ply Tires..................................234
Radio ................................................268 Presets .................................. 262 , 265
Radio Operation ................. 261 , 263 , 270
Radio Screens ........................... 263 , 268
Raising ...............................................47
Raising Four Door ................................47
Raising The Soft Top ............................47
Raising Two Door .................................47
Rear Camera......................................167
Rear Cross Path ...................................88
Rear ParkSense System ......................161
Rear Swing Gate ..................................55
Rear Wiper/Washer ...............................36
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 323