2019 CADILLAC XT4 Emissions system

Cadillac XT4 Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
12017481) - 2019 - CRC - 11/5/18
INSTRUMENTS AND CONTROLS 133
Charging System Light
The charging system light comes on
briefly when the ignition is turned on,
but the engine is not running, as a
check to show the light is working.
It should go out when the engine is
started.
If the light stays on, or comes on
while driving, there may be a problem
with the electrical charging system.
Have it checked by your dealer.
Driving while this light is on could
drain the battery.
When this light comes on, or is
flashing, the Driver Information
Center (DIC) also displays a message.
If a short distance must be driven
with the light on, be sure to turn off
all accessories, such as the radio and
air conditioner.
Malfunction Indicator Lamp
(Check Engine Light)
This light is part of the vehicle’s
emission control on-board diagnostic
system. If this light is on while the
engine is running, a malfunction has
been detected and the vehicle may
require service. The light should come
on to show that it is working when
the ignition is in Service Mode. See
Ignition Positions0184.
Malfunctions are often indicated by
the system before any problem is
noticeable. Being aware of the light
and seeking service promptly when it
comes on may prevent damage.
Caution
If the vehicle is driven continually
with this light on, the emission
control system may not work as
well, the fuel economy may be
lower, and the vehicle may not run
smoothly. This could lead to costly
repairs that might not be covered
by the vehicle warranty.
Caution
Modifications to the engine,
transmission, exhaust, intake,
or fuel system, or the use of
replacement tires that do not meet
the original tire specifications, can
cause this light to come on. This
could lead to costly repairs not
covered by the vehicle warranty.
This could also affect the vehicle’s
ability to pass an Emissions
Inspection/Maintenance test. See
Accessories and Modifications 0254.

Cadillac XT4 Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
12017481) - 2019 - CRC - 11/5/18
134 INSTRUMENTS AND CONTROLS
If the light is f lashing :A
malfunction has been detected that
could damage the emission control
system and increase vehicle
emissions. Diagnosis and service may
be required.
To help prevent damage, reduce
vehicle speed and avoid hard
accelerations and uphill grades.
If towing a trailer, reduce the amount
of cargo being hauled as soon as
possible.
If the light continues to flash, find a
safe place to park. Turn the vehicle off
and wait at least 10 seconds before
restarting the engine. If the light is
still flashing, follow the previous
guidelines and see your dealer for
service as soon as possible.
If the light is on steady : A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
. If fuel has been added to the
vehicle using the capless fuel
funnel adapter, make sure that it
has been removed. See “Filling theTank with a Portable Gas Can
”
under Filling the Tank 0238. The
diagnostic system can detect if the
adapter has been left installed in
the vehicle, allowing fuel to
evaporate into the atmosphere.
A few driving trips with the
adapter removed may turn off the
light.
. Poor fuel quality can cause
inefficient engine operation and
poor driveability, which may go
away once the engine is warmed
up. If this occurs, change the fuel
brand. It may require at least one
full tank of the proper fuel to turn
the light off. See Recommended
Fuel 0237.
If the light remains on, see your
dealer.
Emissions Inspection and
Maintenance Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).
The DLC is under the instrument
panel to the left of the steering wheel.
Connecting devices that are not used
to perform an Emissions Inspection/
Maintenance test or to service the
vehicle may affect vehicle operation.
See Add-On Electrical Equipment 0250.
See your dealer if assistance is needed.
The vehicle may not pass
inspection if:
. The light is on when the engine is
running.
. The light does not come on when
the ignition is in Service Mode.
. Critical emission control systems
have not been completely
diagnosed. If this happens, the
vehicle would not be ready for
inspection and might require
several days of routine driving
before the system is ready for
inspection. This can happen if the

Cadillac XT4 Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
12017481) - 2019 - CRC - 11/5/18
186 DRIVING AND OPERATING
continue until the engine starts. The
ignition will then remain on. See
Starting the Engine0186.
Service Mode
This mode is available to verify the
proper operation of the malfunction
indicator lamp as may be required for
emissions inspection purposes and for
service and diagnostics. See Automatic
Transmission 0194.
With the vehicle off, and the brake
pedal not applied, pressing and
holding ENGINE START/STOP for
more than five seconds will place the
vehicle in Service Mode. The
instruments and audio systems will
operate as they do in ON/RUN, but
the vehicle will not be able to be
driven. The engine will not start in
Service Mode. Press ENGINE START/
STOP again to turn the vehicle off.
Starting the Engine
Place the transmission in the proper
gear, P (Park) or N (Neutral). To restart
the engine when the vehicle is already
moving, use N (Neutral).
Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped.
Caution
If you add electrical parts or
accessories, you could change the
way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty. See
Add-On Electrical Equipment 0250.
To start the vehicle: 1. With the Keyless Access system, the RKE transmitter must be in
the vehicle. Press ENGINE
START/STOP with the brake
pedal applied. When the engine
begins cranking, let go of the
button. The idle speed will go down as the engine warms up.
Do not race the engine
immediately after starting it.
If the RKE transmitter is not in
the vehicle, if there is
interference, or if the RKE
battery is low, a Driver
Information Center (DIC)
message will display. See
Remote
Keyless Entry (RKE) System
Operation 029.Caution
Cranking the engine for long
periods of time, by pressing
ENGINE START/STOP immediately
after cranking has ended, can
overheat and damage the cranking
motor, and drain the battery. Wait
at least 15 seconds between each
try, to let the cranking motor
cool down.
2. If the engine does not start after five to 10 seconds, especially in
very cold weather (below −18 °C
or 0 °F), it could be flooded with
too much gasoline. Try pushing

Cadillac XT4 Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
12017481) - 2019 - CRC - 11/5/18
DRIVING AND OPERATING 237
Recommended Fuel
Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
Premium unleaded gasoline meeting
ASTM specification D4814 with a
posted octane rating of 93 is highly
recommended for best performance
and fuel economy. Unleaded gasoline
with an octane rated as low as 87 can
be used. Using unleaded gasoline
rated below 93 octane, however, will
lead to reduced acceleration and fuel
economy. If knocking occurs, use a
gasoline rated at 93 octane as soon as
possible, otherwise, the engine could
be damaged. If heavy knocking is
heard when using gasoline with a
93 octane rating, the engine needs
service.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so may
damage the vehicle and void its
warranty:. For vehicles that are not
FlexFuel, fuel labeled greater
than 15% ethanol by volume,
such as mid-level ethanol
blends (16–50% ethanol), E85,
or FlexFuel.
. Fuel with any amount of
methanol, methylal, ferrocene,
and aniline. These fuels can
corrode metal fuel system
parts or damage plastic and
rubber parts.
. Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(MMT), which can damage
the emissions control system
and spark plugs.
(Continued)
Caution (Continued)
.Fuel with a posted octane
rating of less than the
recommended fuel. Using this
fuel will lower fuel economy
and performance, and may
decrease the life of the
emissions catalyst.
Fuels in Foreign Countries
The U.S., Canada, and Mexico post
fuel octane ratings in anti-knock index
(AKI). For fuel not to use in a foreign
country, see Prohibited Fuels 0237.
Fuel Additives
TOP TIER Detergent Gasoline is highly
recommended for use with your
vehicle. If your country does not have
TOP TIER Detergent Gasoline, add
ACDelco Fuel System Treatment Plus
−Gasoline to the vehicle’s gasoline fuel
tank at every oil change or 15,000 km
(9,000 mi), whichever occurs first. TOP
TIER Detergent Gasoline and ACDelco
Fuel System Treatment Plus−Gasoline

Cadillac XT4 Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
12017481) - 2019 - CRC - 11/5/18
254 VEHICLE CARE
California Perchlorate
Materials Requirements
Certain types of automotive
applications, such as airbag initiators,
seat belt pretensioners, and lithium
batteries contained in Remote Keyless
Entry transmitters, may contain
perchlorate materials. Special
handling may be necessary. For
additional information, see
www.dtsc.ca.gov/hazardouswaste/
perchlorate.
Accessories and
Modifications
Adding non-dealer accessories or
making modifications to the vehicle
can affect vehicle performance and
safety, including such things as
airbags, braking, stability, ride and
handling, emissions systems,
aerodynamics, durability, and
electronic systems like antilock
brakes, traction control, and stability
control. These accessories or
modifications could even cause
malfunction or damage not covered by
the vehicle warranty.Damage to suspension components
caused by modifying vehicle height
outside of factory settings will not be
covered by the vehicle warranty.
Damage to vehicle components
resulting from modifications or the
installation or use of non-GM certified
parts, including control module or
software modifications, is not covered
under the terms of the vehicle
warranty and may affect remaining
warranty coverage for affected parts.
GM Accessories are designed to
complement and function with other
systems on the vehicle. See your
dealer to accessorize the vehicle using
genuine GM Accessories installed by a
dealer technician.
Also, see
Adding Equipment to the
Airbag-Equipped Vehicle 091.
Vehicle Checks
Doing Your Own
Service Work
{Warning
It can be dangerous to work on
your vehicle if you do not have the
proper knowledge, service manual,
tools, or parts. Always follow
owner’s manual procedures and
consult the service manual for your
vehicle before doing any
service work.
If doing some of your own service
work, use the proper service manual.
It tells you much more about how to
service the vehicle than this manual
can. To order the proper service
manual, see Publication Ordering
Information 0349.
This vehicle has an airbag system.
Before attempting to do your own
service work, see Servicing the
Airbag-Equipped Vehicle 091.