2021 CADILLAC XT4 check engine

Cadillac XT4 Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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272 DRIVING AND OPERATING
.Automatic Emergency
Braking (AEB)
.Intelligent Brake Assist (IBA)
.Front Pedestrian Braking (FPB)
If equipped with Lane Change Alert
(LCA), the LCA detection zones that
extend back from the side of the
vehicle do not move further back
when a trailer is towed. Use caution
while changing lanes when towing a
trailer.
If equipped with Rear Cross Traffic
Alert (RCTA), use caution while
backing up when towing a trailer, as
the RCTA detection zones that extend
out from the back of the vehicle do
not move further back when a trailer
is towed.
{Warning
To prevent serious injury or death
from carbon monoxide (CO), when
towing a trailer:
.Do not drive with the liftgate,
trunk/hatch, or rear-most
window open. (Continued)
Warning (Continued)
.Fully open the air outlets on or
under the instrument panel.
.Adjust the climate control
system to a setting that brings in
only outside air. See“Climate
Control Systems” in the Index.
For more information about carbon
monoxide, see Engine Exhaust
0 226.
Towing a trailer requires experience.
The combination of the vehicle and
trailer is longer and not as responsive
as the vehicle itself. Get used to the
handling and braking of the
combination by driving on a level road
surface before driving on public roads.
The trailer structure, the tires, and the
brakes must be all be rated to carry
the intended cargo. Inadequate trailer
equipment can cause the combination
to operate in an unexpected or unsafe
manner. Before driving, inspect all
trailer hitch parts and attachments,
safety chains, electrical connectors,
lamps, tires, and mirrors. See Towing
Equipment 0277. If the trailer has electric brakes, start the combination
moving and then manually apply the
trailer brake controller to check that
the trailer brakes work. During the
trip, occasionally check that the cargo
and trailer are secure and that the
lamps and any trailer brakes are
working.
Towing with a Stability Control
System
When towing, the stability control
system might be heard. The system
reacts to vehicle movement caused by
the trailer, which mainly occurs
during cornering. This is normal when
towing heavier trailers.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving without a trailer. This can help
to avoid heavy braking and sudden
turns.
Passing
More passing distance is needed when
towing a trailer. The combination of
the vehicle and trailer will not
accelerate as quickly and is much

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274 DRIVING AND OPERATING
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
.Start the engine.
.Shift into a gear.
.Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer
Towing
The vehicle needs service more often
when used to tow trailers. See
Maintenance Schedule 0358. It is
especially important to check the
automatic transmission fluid, engine
oil, axle lubricant, belts, cooling
system, and brake system before and
during each trip.
Check periodically that all nuts and
bolts on the trailer hitch are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 294.
Trailer Towing
Caution
Towing a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To tow a trailer
correctly, follow the directions in
this section and see your dealer for
important information about
towing a trailer with the vehicle.
Trailering is different than just driving
the vehicle by itself. Trailering means
changes in handling, acceleration,
braking, durability, and fuel economy.
Successful, safe trailering takes correct
equipment, and it has to be used
properly.
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are important for your safety and that of
your passengers. Read this section
carefully before pulling a trailer.
Trailer Weight
{Warning
Never exceed the towing capacity
for your vehicle.
Safe trailering requires monitoring the
weight, speed, altitude, road grades,
outside temperature, dimensions of
the front of the trailer, and how
frequently the vehicle is used to tow a
trailer.
When towing a trailer, the combined
weight of the vehicle, vehicle contents,
trailer, and trailer contents must be
below all of the maximum weight
ratings for the vehicle, including:
.GCWR: Gross Combined Weight
Rating
.GVWR: Gross Vehicle Weight Rating
.Maximum Trailer Weight Rating
.Maximum Trailer Tongue Weight
Rating

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DRIVING AND OPERATING 279
Trailer Wiring Harness
Basic Trailer Wiring
The trailer wiring harness is located at
the rear of the vehicle and is tied to
the vehicle's frame. The harness
connector can be plugged into a
trailer connector available through
your dealer.
Trailer Lamps
Always check all trailer lamps are
working at the beginning of each trip,
and periodically on longer trips.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing lanes,
or stopping. When towing a trailer,
the arrows on the instrument cluster
will illuminate even if the trailer is not
properly connected or the bulbs are
burned out.
Trailer Sway Control (TSC)
Vehicles with StabiliTrak/Electronic
Stability Control (ESC) have a Trailer
Sway Control (TSC) feature. Trailersway is unintended side-to-side
motion of a trailer while towing. If the
vehicle is towing a trailer and the TSC
detects that sway is increasing, the
vehicle brakes are selectively applied
at each wheel, to help reduce
excessive trailer sway. If equipped with
the Integrated Trailer Brake Control
(ITBC) system, and the trailer has an
electric brake system, StabiliTrak/ESC
may also apply the trailer brakes.
If TSC is enabled, the Traction Control
System (TCS)/StabiliTrak/ESC warning
light will flash on the instrument
cluster. Reduce vehicle speed by
gradually removing your foot from the
accelerator. If trailer sway continues,
StabiliTrak/ESC can reduce engine
torque to help slow the vehicle. TSC
will not function if StabiliTrak/ESC is
turned off. See
Traction Control/
Electronic Stability Control 0235.
{Warning
Trailer sway can result in a crash
and in serious injury or death, even
if the vehicle is equipped with TSC.
If the trailer begins to sway, reduce
vehicle speed by gradually removing
your foot from the accelerator. Then
pull over to check the trailer and
vehicle to help correct possible
causes, including an improperly or
overloaded trailer, unrestrained
cargo, improper trailer hitch
configuration, or improperly
inflated or incorrect vehicle or
trailer tires. See Towing Equipment
0 277 for trailer ratings and hitch
setup recommendations.
Trailer Tires
Special Trailer (ST) tires differ from
vehicle tires. Trailer tires are designed
with stiff sidewalls to help prevent
sway and to support heavy loads.
These features can make it difficult to
determine if the trailer tire pressures
are low only based on a visual
inspection.

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280 DRIVING AND OPERATING
Always check all trailer tire pressures
before each trip when the tires are
cool. Low trailer tire pressure is a
leading cause of trailer tire blow-outs.
Trailer tires deteriorate over time. The
trailer tire sidewall will show the week
and year the tire was manufactured.
Many trailer tire manufacturers
recommend replacing tires more than
six years old.
Overloading is another leading cause
of trailer tire blow-outs. Never load
your trailer with more weight than the
tires are designed to support. The load
rating is located on the trailer tire
sidewall.
Always know the maximum speed
rating for the trailer tires before
driving. This may be significantly
lower than the vehicle tire speed
rating. The speed rating may be on
the trailer tire sidewall. If the speed
rating is not shown, the default trailer
tire speed rating is 105 km/h
(65 mph).Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. SeeMalfunction Indicator
Lamp (Check Engine Light) 0105.
A device connected to the DLC —
such as an aftermarket fleet or
driver-behavior tracking device —
may interfere with vehicle systems.
This could affect vehicle operation
and cause a crash. Such devices
may also access information stored
in the vehicle’s systems.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and would (Continued)
Caution (Continued)
not be covered by the vehicle
warranty. Always check with your
dealer before adding electrical
equipment.
Add-on equipment can drain the
vehicle's 12-volt battery, even if the
vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see Servicing
the Airbag-Equipped Vehicle 064 and
Adding Equipment to the
Airbag-Equipped Vehicle 064.

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VEHICLE CARE 281
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 282
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 282
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 282
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 283
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 283
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 285
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 286
Engine Oil Life System . . . . . . . . . . . 288
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
Engine Air Filter Life System . . . . 289
Engine Air Cleaner/Filter . . . . . . . . . 290
Cooling System . . . . . . . . . . . . . . . . . . . 291
Engine Overheating . . . . . . . . . . . . . . 294
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 295
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 296
Battery - North America . . . . . . . . . 297
All-Wheel Drive . . . . . . . . . . . . . . . . . . 298 Park Brake and P (Park)
Mechanism Check . . . . . . . . . . . . . . 298
Wiper Blade Replacement . . . . . . . 299
Windshield Replacement . . . . . . . . 300
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 300
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . 301
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 301
LED Lighting . . . . . . . . . . . . . . . . . . . . . 301
Back-Up Lamps . . . . . . . . . . . . . . . . . . . 302
Electrical System
Electrical System Overload . . . . . . 302
Fuses and Circuit Breakers . . . . . . 303
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Instrument Panel Fuse Block . . . . 306
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
All-Season Tires . . . . . . . . . . . . . . . . . . 309
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 310
Summer Tires . . . . . . . . . . . . . . . . . . . . 310
Tire Sidewall Labeling . . . . . . . . . . . 310
Tire Designations . . . . . . . . . . . . . . . . . 312
Tire Terminology and Definitions . . . . . . . . . . . . . . . . . . . . . . 313
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 316 Tire Pressure for High-Speed
Operation . . . . . . . . . . . . . . . . . . . . . . . . 317
Tire Pressure Monitor System . . . 318
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 319
Tire Inspection . . . . . . . . . . . . . . . . . . . 322
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 323
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Buying New Tires . . . . . . . . . . . . . . . . 325
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 326
Uniform Tire Quality Grading . . . 326
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 328
Wheel Replacement . . . . . . . . . . . . . . 328
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 328
If a Tire Goes Flat . . . . . . . . . . . . . . . . 329
Tire Sealant and Compressor Kit . . . . . . . . . . . . . . . . . 331
Storing the Tire Sealant and Compressor Kit . . . . . . . . . . . . . . . . . 336
Tire Changing . . . . . . . . . . . . . . . . . . . . . 337
Compact Spare Tire . . . . . . . . . . . . . . 341
Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . . . . . . . 342

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284 VEHICLE CARE
Hood
{Warning
For vehicles with auto engine stop/
start, turn the vehicle off before
opening the hood. If the vehicle is
on, the engine will start when the
hood is opened. You or others could
be injured.
{Warning
Components under the hood can
get hot from running the engine. To
help avoid the risk of burning
unprotected skin, never touch these
components until they have cooled,
and always use a glove or towel to
avoid direct skin contact.
Clear any snow from the hood before
opening.
To open the hood: 1. Pull the hood release lever with the
isymbol. It is on the lower left
side of the instrument panel.
2. Go to the front of the vehicle and locate the secondary release lever
under the front center of the hood.
Push the secondary hood release
lever to the right to release.
3. After you have partially lifted the hood, the gas strut system will
automatically lift the hood and
hold it in the fully open position. To close the hood:
1. Before closing the hood, be sure all filler caps are on properly, and all
tools are removed.
2. Pull the hood down until the strut system is no longer holding up
the hood.
3. Allow the hood to fall. Check to make sure the hood is latched
completely. Repeat this process
with additional force if necessary.{Warning
Do not drive the vehicle if the hood
is not latched completely. The hood
could open fully, block your vision,
and cause a crash. You or others
could be injured. Always close the
hood completely before driving.

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286 VEHICLE CARE
1.Engine Air Cleaner/Filter 0290.
2. Engine Oil Fill Cap. See Engine Oil
0 286.
3. Engine Oil Dipstick. See Engine Oil
0 286.
4. Engine Cooling Fan (Out of View). See Cooling System 0291.
5. Brake Fluid Reservoir. See Brake
Fluid 0296.
6. Battery - North America 0297.
7. Engine Coolant Surge Tank and Pressure Cap. See Cooling System
0 291.
8. Positive (+) Battery Terminal (Under Cover). See Jump Starting -
North America 0342.
9. Windshield Washer Fluid Reservoir. See Washer Fluid 0295.
10. Engine Compartment Fuse Block
0303.
11. Remote Negative (-) Battery Terminal. See Jump Starting - North
America 0342.Engine Oil
To ensure proper engine performance
and long life, careful attention must
be paid to engine oil. Following these
simple, but important steps will help
protect your investment:
.Use engine oil approved to the
proper specification and of the
proper viscosity grade. See
“Selecting the Right Engine Oil” in
this section.
.Check the engine oil level regularly
and maintain the proper oil level.
See “Checking Engine Oil” and
“When to Add Engine Oil” in this
section.
.Change the engine oil at the
appropriate time. See Engine Oil Life
System 0288.
.Always dispose of engine oil
properly. See “What to Do with Used
Oil” in this section.
Checking Engine Oil
Check the engine oil level regularly,
every 650 km (400 mi), especially prior
to a long trip. The engine oil dipstick handle is a loop. See
Engine
Compartment Overview 0285 for the
location.
{Warning
The engine oil dipstick handle may
be hot; it could burn you. Use a
towel or glove to touch the dipstick
handle.
If a low oil Driver Information Center
(DIC) message displays, check the oil
level.
Follow these guidelines:
.To get an accurate reading, park the
vehicle on level ground. Check the
engine oil level after the engine has
been off for at least two hours.
Checking the engine oil level on
steep grades or too soon after
engine shutoff can result in
incorrect readings. Accuracy
improves when checking a cold
engine prior to starting. Remove the
dipstick and check the level.
.If unable to wait two hours, the
engine must be off for at least
15 minutes if the engine is warm,
or at least 30 minutes if the engine

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VEHICLE CARE 287
is not warm. Pull out the dipstick,
wipe it with a clean paper towel or
cloth, then push it back in all the
way. Remove it again, keeping the
tip down, and check the level.
When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick and the
engine has been off for at least
15 minutes, add 1 L (1 qt) of the
recommended oil and then recheck
the level. See“Selecting the Right
Engine Oil” later in this section for an
explanation of what kind of oil to use.
For engine oil crankcase capacity, see
Capacities and Specifications 0371.
Caution
Do not add too much oil. Oil levels
above or below the acceptable
operating range shown on the
(Continued)
Caution (Continued)
dipstick are harmful to the engine.
If the oil level is above the
operating range (i.e., the engine has
so much oil that the oil level gets
above the cross-hatched area that
shows the proper operating range),
the engine could be damaged. Drain
the excess oil or limit driving of the
vehicle, and seek a service
professional to remove the
excess oil.
See Engine Compartment Overview
0 285 for the location of the engine oil
fill cap.
Add enough oil to put the level
somewhere in the proper operating
range. Push the dipstick all the way
back in when through.
Selecting the Right Engine Oil
Selecting the right engine oil depends
on both the proper oil specification
and viscosity grade. See Recommended
Fluids and Lubricants 0367. Specification
Use full synthetic engine oils that
meet the dexos1 specification.
Engine oils that have been approved
by GM as meeting the dexos1
specification are marked with the
dexos1 approved logo. See
www.gmdexos.com.
Caution
Failure to use the recommended
engine oil or equivalent can result
in engine damage not covered by
the vehicle warranty.
Viscosity Grade
Use SAE 0W-20 viscosity grade
engine oil.