2023 JEEP WRANGLER check engine light

GETTING TO KNOW YOUR INSTRUMENT PANEL123
GREEN INDICATOR LIGHTS
Adaptive Cruise Control (ACC) Set With No
Target Detected Indicator Light —
If Equipped
This light will turn on when the Adaptive Cruise
Control is set and there is no vehicle in front
detected
Úpage 152.
Adaptive Cruise Control (ACC) Set With
Target Indicator Light — If Equipped
This will display when the ACC is set and a
vehicle in front is detected Úpage 152.
4WD Auto Indicator Light — If Equipped
This light alerts the driver that the vehicle is in
the Four-Wheel Drive auto mode. The system
will provide power to all four wheels and shift the power between the front and rear axles as needed.
This will provide maximum traction in dry and slippery
conditions.
Cruise Control SET Indicator Light —
If Equipped With A Premium Instrument
Cluster
This indicator light will illuminate when the
Cruise Control is set to the desired speed
Úpage 151.
Front Fog Indicator Light — If Equipped
This indicator light will illuminate when the
front fog lights are on Úpage 50.
Parking/Headlights On Indicator Light
This indicator light will illuminate when the
parking lights or headlights are turned on.
Stop/Start Active Indicator Light —
If Equipped
This indicator light will illuminate when the
Stop/Start function is in “Autostop” mode.
Turn Signal Indicator Lights
When the left or right turn signal is activated,
the turn signal indicator will flash
independently and the corresponding exterior
turn signal lamps will flash. Turn signals can be activated when the multifunction lever is moved down
(left) or up (right).
NOTE:

A continuous chime will sound if the vehicle is driven
more than 1 mile (1.6 km) with either turn signal on.
 Check for an inoperative outside light bulb if either indi -
cator flashes at a rapid rate.
WHITE INDICATOR LIGHTS
Adaptive Cruise Control (ACC) Ready
Indicator Light — If Equipped
This light will turn on when the vehicle
equipped with ACC has been turned on, but not
set.
2WD High Indicator Light — If Equipped
With a Premium Instrument Cluster
This light alerts the driver that the vehicle is in
the Two-Wheel Drive High mode.

Hill Descent Control (HDC) Indicator Light —
If Equipped

This indicator shows when the HDC feature is
turned on. The light will be on solid when HDC
is armed. HDC can only be armed when the
transfer case is in the 4WD Low position and
the vehicle speed is less then 30 mph (48 km/h). If these
conditions are not met while attempting to use the HDC
feature, the HDC indicator light will flash on/off.
CAUTION!
The presence of water in the fuel system circuit may
cause severe damage to the injection system and
irregular engine operation. If the indicator light is
illuminated, contact an authorized dealer as soon as
possible to bleed the system. If the indicator comes on
immediately after refuelling, water, or AdBlue® UREA
has probably been poured into the tank: switch the
engine off immediately and contact an authorized
dealer.
3

23_JL_OM_EN_USC_t.book Page 123

GETTING TO KNOW YOUR INSTRUMENT PANEL125
ONBOARD DIAGNOSTIC SYSTEM
(OBD II) C
YBERSECURITY
Your vehicle is required to have 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 access this information to
assist with the diagnosis and service of your vehicle and
emissions system
Úpage 184.
EMISSIONS INSPECTION AND
MAINTENANCE PROGRAMS
In some localities, it may be a legal requirement to pass an
inspection of your vehicle's emissions control system.
Failure to pass could prevent vehicle registration.
For states that require an Inspection and
Maintenance (I/M), this check verifies the
Malfunction Indicator Light (MIL) is functioning
and is not on when the engine is running, and
that the OBD II system is ready for testing.
The OBD II system may not be ready if your vehicle was
recently serviced, recently had a depleted 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.

NOTE:If you crank or start the engine, you will have to start this
test over.
2. As soon as you cycle the ignition switch to the ON position, you will see the Malfunction Indicator Light
(MIL) symbol come on as part of a normal bulb check. 3. Approximately 15 seconds later, one of two things will
happen:
 The MIL will flash for about 10 seconds and then
return to being fully illuminated until you turn OFF
the ignition or start the engine. This means that
your vehicle's OBD II system is not ready and you
should not proceed to the I/M station.
 The MIL will not flash at all and will remain fully illu -
minated until you place the ignition in the off posi -
tion or start the engine. This means that your
vehicle's OBD II system is ready and you can
proceed to the I/M station.
If your OBD II system is not ready, you should see an
authorized dealer or repair facility. If your vehicle was
recently serviced or had a battery failure or replacement,
you may need to do nothing more than drive your vehicle
as you normally would in order for your OBD II system to
update. A recheck with the previously mentioned test
routine may then indicate that the system is now ready.
Regardless of whether your vehicle's OBD II system is
ready or not, if the MIL is illuminated during normal vehicle
operation you should have your vehicle serviced before
going to the I/M station. The I/M station can fail your
vehicle because the MIL is on with the engine running.
WARNING!
 ONLY an authorized service technician should
connect equipment to the OBD II connection port in
order to read the VIN, diagnose, or service your
vehicle.
 If unauthorized equipment is connected to the OBD II
connection port, such as a driver-behavior tracking
device, it may:
 Be possible that vehicle systems, including
safety related systems, could be impaired or a
loss of vehicle control could occur that may
result in an accident involving serious injury or
death.
 Access, or allow others to access, information
stored in your vehicle systems, including
personal information.
3

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130STARTING AND OPERATING
NORMAL STARTING
Observe the instrument cluster lights when starting the
engine.
NOTE:Normal starting of either a cold or a warm engine is
obtained without pumping or pressing the accelerator
pedal.

1. Always apply the parking brake.

2. Press and hold the brake pedal while pushing the
ENGINE START/STOP button once.
NOTE:A delay of the start of up to five seconds is possible under
very cold conditions. The Wait to Start telltale will be illumi -
nated during the preheat process. When the engine Wait
To Start telltale goes off the engine will automatically
crank.
3. The system will automatically engage the starter to crank the engine. If the vehicle fails to start, the
starter will disengage automatically after 25 seconds.
4. If you wish to stop the cranking of the engine prior to the engine starting, push the ENGINE START/STOP
button again. 5. Check that the Oil Pressure Warning Light has turned
off.
6. Release the parking brake.
STARTING FLUIDS
The engine is equipped with a glow plug preheating
system. If the instructions in this manual are followed, the
engine should start in all conditions and no type of starting
fluid should be used.
NORMAL OPERATION — DIESEL ENGINE
Observe the following when the diesel engine is operating:
 All message center lights are off.
 Malfunction Indicator Light (MIL) is off.
 Engine Oil Pressure telltale is not illuminated.
 Voltmeter operation.
The voltmeter may show a gauge fluctuation at various
engine temperatures. This is caused by the glow plug
heating system. The number of cycles and the length of
the cycling operation is controlled by the engine control
module. Glow plug heater operation can run for several
minutes. Once the heater operation is complete, the
voltmeter needle will stabilize.
CAUTION!
If the Water in Fuel Indicator Light remains on, DO NOT
START the engine before you drain the water from the
fuel filters to avoid engine damage
Úpage 321.
WARNING!
 Do not leave children or animals inside parked vehi -
cles in hot weather. Interior heat buildup may cause
serious injury or death.
 When leaving the vehicle, always make sure the
keyless ignition node is in the OFF position, remove
the key fob from the vehicle and lock the vehicle.
 Never leave children alone in a vehicle, or with
access to an unlocked vehicle. Allowing children to
be in a vehicle unattended is dangerous for a
number of reasons. A child or others could be seri -
ously or fatally injured. Children should be warned
not to touch the parking brake, brake pedal or the
gear selector.
 Do not leave the key fob in or near the vehicle, or in
a location accessible to children, and do not leave
the ignition of a vehicle equipped with Keyless
Enter ‘n Go™ in the ACC or ON/RUN position. A child
could operate power windows, other controls, or
move the vehicle.

23_JL_OM_EN_USC_t.book Page 130

132STARTING AND OPERATING
STOPPING THE ENGINE
After full load operation, idle the engine for a few minutes before shutting it down. This idle period will allow the lubricating oil and coolant to carry excess heat away from the
turbocharger.
NOTE:Refer to the following chart for proper engine shutdown.
NOTE:Under certain conditions the engine fan will run after the
engine is turned off. These conditions are under high load
and high temperature conditions.
COOLING SYSTEM TIPS — AUTOMATIC
T
RANSMISSION
To reduce the potential for engine and transmission
overheating in high ambient temperature conditions, take
the following actions:
 City Driving — When stopped, shift the transmission
into NEUTRAL (N) and increase engine idle speed.
 Highway Driving — Reduce your speed. 
Up Steep Hills — Select a lower transmission gear.
 Air Conditioning — Turn it off temporarily.
NOTE:If the coolant temperature is too high, the A/C will auto -
matically turn off.
Do Not Operate The Engine With Low Oil
Pressure
If the Oil Pressure Warning Light turns on while driving,
stop the vehicle and shut down the engine as soon as
possible. A chime will sound when the light turns on. After
the vehicle is safely stopped, restart the engine and
monitor the Oil Pressure Warning Light. If the Oil Pressure
Warning Light is still illuminated, turn the engine OFF and contact an authorized dealer for further assistance. If the
lamp is no longer illuminated, the engine can be operated
but it is recommended to take the vehicle to an authorized
dealer as soon as possible.
NOTE:Do not operate the vehicle until the cause is corrected.
This light does not show how much oil is in the engine. The
engine oil level must be checked under the hood.
Driving Condition Load Turbocharger Temperature Idle Time (min.) Before Engine Shutdown
Stop and Go EmptyCoolNone
Stop and Go Medium 0.5
Highway Speeds MediumWarm 1.0
City Traffic Maximum GCWR 1.5
Highway Speeds Maximum GCWR 2.0
Uphill Grade Maximum GCWR Hot2.5
CAUTION!
If oil pressure falls to less than normal readings, shut
the engine off immediately. Failure to do so could result
in immediate and severe engine damage.

23_JL_OM_EN_USC_t.book Page 132

STARTING AND OPERATING133
Do Not Operate The Engine With Failed
Parts
All engine failures give some warning before the parts fail.
Be on the alert for changes in performance, sounds, and
visual evidence that the engine requires service. Some
important clues are:
Engine misfiring or vibrating severely
 Sudden loss of power
 Unusual engine noises
 Fuel, oil or coolant leaks
 Sudden change, outside the normal operating range, in
the engine operating temperature
 Excessive smoke
 Oil pressure drop
ENGINE BREAK-IN RECOMMENDATIONS —
GASOLINE ENGINE (IF EQUIPPED)
A long break-in period is not required for the engine and
drivetrain (transmission and axle) in your vehicle.
Drive moderately during the first 300 miles (500 km).
After the initial 60 miles (100 km), speeds up to 50 or
55 mph (80 or 90 km/h) are desirable.
While cruising, brief full-throttle acceleration within the
limits of local traffic laws contributes to a good break-in.
Wide-open throttle acceleration in low gear can be
detrimental and should be avoided.
The engine oil installed in the engine at the factory is a
high-quality energy conserving type lubricant. Oil changes
should be consistent with anticipated climate conditions
under which vehicle operations will occur. For the recommended viscosity and quality grades
Úpage 374.
NOTE:A new engine may consume some oil during its first few
thousand miles (kilometers) of operation. This should be
considered a normal part of the break-in and not inter
-
preted as a problem.
ENGINE BREAK-IN RECOMMENDATIONS —
DIESEL ENGINE (IF EQUIPPED)
The diesel engine does not require a break-in period due
to its construction. Normal operation is allowed, providing
the following recommendations are followed:
 Warm up the engine before placing it under load.
 Do not operate the engine at idle for prolonged periods.
 Use the appropriate transmission gear to prevent
engine lugging.
 Observe vehicle oil pressure and temperature indica -
tors.
 Check the coolant and oil levels frequently.
 Vary throttle position at highway speeds when carrying
or towing significant weight.
NOTE:Light duty operation such as light trailer towing or no load
operation will extend the time before the engine is at full
efficiency. Reduced fuel economy and power may be seen
at this time.
The engine oil installed in the engine at the factory is a
high-quality energy conserving type lubricant. Oil changes
should be consistent with anticipated climate conditions
under which vehicle operations will occur. For
recommended viscosity and quality grades see
Úpage 374. NON-DETERGENT OR STRAIGHT MINERAL
OILS MUST NEVER BE USED.
PARKING BRAKE
Before exiting the vehicle, make sure that the parking
brake is fully applied. Also, be certain to leave an
automatic transmission in PARK, or manual transmission
in REVERSE or FIRST gear.
The parking brake lever is located in the center console.
To apply the parking brake, pull the lever up as firmly as
possible. To release the parking brake, pull the lever up
slightly, push the center button, then lower the lever
completely.
CAUTION!
Never use Non-Detergent Oil or Straight Mineral Oil in
the engine or damage may result.
4

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148STARTING AND OPERATING
POSSIBLE REASONS THE ENGINE DOES
N
OT AUTOSTOP
Prior to engine shut down, the system will check many
safety and comfort conditions to see if they are fulfilled.
Detailed information about the operation of the Stop/Start
system may be viewed in the instrument cluster display
Stop/Start screen. Situations when the engine will not
stop include (but not limited to):
 Driver’s seat belt is not buckled.
 Driver’s door is not closed.
 Battery temperature is too warm or cold.
 Battery charge is low.
 The vehicle is on a steep grade.
 Cabin heating or cooling is in process and an accept -
able cabin temperature has not been achieved.
 Gear selector is in MANUAL (M) mode.
 HVAC is set to full defrost mode at a high blower speed.
 HVAC is set to MAX A/C.
 Engine has not reached normal operating temperature.
 Engine or exhaust temperature is too high.
 The transmission is not in a forward gear.
 Hood is open.
 Transfer case is in 4L or N (Neutral).
 Brake pedal is not pressed with sufficient pressure.
 Accelerator pedal input.
 Vehicle speed threshold has not been achieved from
previous Autostop.
 Steering angle is beyond threshold (ESS Models Only).
 ACC is on and speed is set.
 Vehicle is at high altitude.
 System fault is present. It may be possible for the vehicle to be driven several
times without the Stop/Start system going into a STOP/
START READY state under more extreme conditions of the
previously listed items.
TO START THE ENGINE WHILE IN
A
UTOSTOP MODE
While in a forward gear, the engine will start when the
brake pedal is released or the throttle pedal is pressed.
The transmission will automatically re-engage upon
engine restart.
Conditions That Will Cause The Engine To Start
Automatically While In Autostop Mode:
 The transmission selector is moved out of DRIVE.
 To maintain cabin temperature comfort.
 Actual cabin temperature is significantly different than
temperature set on Auto HVAC.
 HVAC is set to full defrost mode.
 HVAC system temperature or fan speed is manually
adjusted higher.
 Battery voltage drops too low.
 Stop/Start OFF switch is pushed.
 A Stop/Start system error occurs.
 Stop/Start Autostop Active time exceeds five minutes.
 Transfer case is in 4L or N (Neutral).
 Steering wheel is turned beyond threshold (ESS
Models Only).
TO MANUALLY TURN OFF THE STOP/
S
TART SYSTEM

Stop/Start OFF Switch

Push the Stop/Start OFF switch (located on the switch
bank). The light on the switch will illuminate. The “Stop/
Start OFF” message will appear in instrument cluster
display within the Stop/Start section, and the autostop
function will be disabled
Úpage 108.
NOTE:The Stop/Start system will reset itself back to an ON
condition every time the ignition is turned off and back on.

23_JL_OM_EN_USC_t.book Page 148

STARTING AND OPERATING149
TO MANUALLY TURN ON THE STOP/
S
TART SYSTEM
Push the Stop/Start OFF switch (located on the switch
bank). The light on the switch will turn off.
SYSTEM MALFUNCTION
If there is a malfunction in the Stop/Start system, the
system will not shut down the engine. A “SERVICE STOP/
START SYSTEM” message and a yellow Stop/Start telltale
will appear in the Instrument Cluster Display
Úpage 108.
If the “SERVICE STOP/START SYSTEM” message appears
in the instrument cluster display, have the system
checked by an authorized dealer.
If a malfunction occurs during an autostop, the vehicle
may not auto start and will need a key start.
STOP/START SYSTEM — MANUAL
TRANSMISSION (IF EQUIPPED)
The Engine Stop/Start (ESS) function is designed to
reduce fuel consumption. The system will stop the engine
automatically during a vehicle stop if the required
conditions are met. Pressing the clutch pedal will
automatically restart the vehicle.
ESS vehicles have been upgraded with a heavy-duty
starter, enhanced battery, and other upgraded engine
parts, to handle the additional engine starts. Vehicles
equipped with eTorque contain a heavy duty motor generator and an additional hybrid electric battery to store
energy from vehicle deceleration for use on engine startup
after a stop as well as providing launch torque assist.
NOTE:It is recommended that Stop/Start be disabled during
off-road use.
Secondary Battery
Your vehicle may be equipped with a secondary battery
used to power the Stop/Start system and the 12 Volt
vehicle electrical system. The secondary battery is located
behind the wheel well for the front passenger wheel.

Battery Locations

AUTOSTOP MODE
The Stop/Start feature is enabled after every driver
ignition start. It will remain in STOP/START NOT READY
until you drive forward with a vehicle speed greater than
5 mph (8 km/h). At that time, the system will go into
STOP/START READY and if all other conditions are met,
can go into an STOP/START AUTO STOP ACTIVE mode.
To Activate The STOP/START AUTOSTOP ACTIVE Mode,
The Following Must Occur:
 The system must be in STOP/START READY state. A
STOP/START READY message will be displayed in the
instrument cluster
Úpage 108.
 Vehicle speed must be less than 2 mph (3 km/h).
 The gear selector must be in the NEUTRAL position and
the clutch pedal must be fully released.
1 — Primary Battery
2 — Secondary Battery
WARNING!

Vehicles with the Stop/Start system will be equipped
with two batteries. Both the main and the supple -
mental batteries must be disconnected to
completely de-energize the 12 Volt electrical system.
 Serious injury or death could result if you do not
disconnect both batteries. To learn how to properly
disconnect, see an authorized dealer.
4

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150STARTING AND OPERATING
POSSIBLE REASONS THE ENGINE DOES
N
OT AUTOSTOP
Prior to engine shut down, the system will check many
safety and comfort conditions to see if they are fulfilled.
Situations when the engine will not stop include (but not
limited to):
 Driver’s seat belt is not buckled.
 Outside temperature is less than 10°F (–12°C) or
greater than 109°F (43°C).
 Actual cabin temperature is significantly different than
temperature set on Auto HVAC.
 HVAC is set to full defrost mode.
 Engine has not reached normal operating temperature.
 Battery is discharged.
 When driving in REVERSE.
 Hood is open.
 Transfer case is in 4L or N (Neutral).
 Driver's seat is not occupied or driver’s door is open.
 Vehicle is at high altitude.
 The vehicle is on a steep grade.
 Forward Gear is engaged.
 Steering angle is beyond threshold (ESS Models Only).
 System fault is present.
 HVAC is set to MAX A/C.
It may be possible for the vehicle to be driven several
times without the Stop/Start system going into a STOP/
START READY state under more extreme conditions of the
previously listed items.
TO START THE ENGINE WHILE IN
A
UTOSTOP MODE
When the gear selector is in NEUTRAL, the engine will start
when the clutch pedal is pressed (does not require
complete/full pedal press). The vehicle will go into STOP/
START SYSTEM NOT READY mode until the vehicle speed
is greater than 5 mph (8 km/h).
Conditions that will cause the engine to start
automatically while in STOP/START AUTOSTOP ACTIVE
mode
The Engine Will Start Automatically When:
 Actual cabin temperature is significantly different than
temperature set on Auto HVAC.
 HVAC is set to full defrost mode.
 HVAC system temperature or fan speed is manually
adjusted higher.
 Stop/Start Autostop Active time exceeds five minutes.
 Battery voltage drops too low.
 Vehicle is moving faster than 5 mph (8 km/h).
 STOP/START OFF switch is pressed.
 Transfer case is in 4L or N (Neutral).
 Steering wheel is turned beyond threshold (ESS
Models Only).
TO MANUALLY TURN OFF THE STOP/
S
TART SYSTEM

1. Push the Stop/Start OFF switch (located on the
switch bank). The light on the switch will illuminate.

Stop/Start OFF Switch

2. The STOP/START OFF message will appear in the
instrument cluster Úpage 108.
3. At the next vehicle stop (after turning off the Stop/ Start system), the engine will not be stopped.
4. If the Stop/Start system is manually turned off, the engine can only be started and stopped by cycling the
ignition switch.
5. The Stop/Start system will reset itself back to an ON condition every time the ignition is turned off and
back on.

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