engine CADILLAC XT6 2021 Workshop Manual

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
232 DRIVING AND OPERATING
Starting and Operating
New Vehicle Break-In
Caution
The vehicle does not need an
elaborate break-in. But it will
perform better in the long run if
you follow these guidelines:
.Do not drive at any one constant
speed, fast or slow, for the first
800 km (500 mi). Do not make
full-throttle starts. Avoid
downshifting to brake or slow the
vehicle.
.Avoid making hard stops for the
first 300 km (200 mi) or so.
During this time the new brake
linings are not yet broken in.
Hard stops with new linings can
mean premature wear and earlier
replacement. Follow this
breaking-in guideline every time
you get new brake linings.
Following break-in, engine speed
and load can be gradually
increased.
Ignition Positions
The vehicle has an electronic keyless
ignition with pushbutton start.
If the pushbutton start is not working,
the vehicle may be near a strong radio
antenna signal causing interference to
the Remote Keyless Entry (RKE)
system. See Remote Keyless Entry
(RKE) System Operation 07.
To shift out of P (Park), the vehicle
must be turned on and the brake
pedal must be applied. Stopping the Engine/OFF (No
Indicator Light) :
When the vehicle is
stopped, press ENGINE START/STOP
once to turn the engine off.
If the vehicle is in P (Park), the
ignition will turn off, and Retained
Accessory Power (RAP) will remain
active. See Retained Accessory Power
(RAP) 0237.
If the vehicle is in R (Reverse), D
(Drive), or M (Manual Mode), the
vehicle will shift into P (Park), the
ignition will turn off, and RAP will
remain active.
If the vehicle is in N (Neutral), the
ignition will return to ACC/
ACCESSORY and display the message
SHIFT TO PARK in the Driver
Information Center (DIC). When the
vehicle is shifted into P (Park), the
ignition will turn off.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering (Continued)

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 233
Warning (Continued)
systems and disable the airbags.
While driving, only shut the vehicle
off in an emergency.
If the vehicle must be shut off in an
emergency: 1. Brake using a firm and steady pressure. Do not pump the brakes
repeatedly. This may deplete power
assist, requiring increased brake
pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the vehicle
is moving. After shifting to
N (Neutral), firmly apply the brakes
and steer the vehicle to a safe
location.
3. Come to a complete stop and shift to P (Park).
4. Set the parking brake. See Electric
Parking Brake 0246. Press ENGINE
START/STOP to turn the
vehicle off. If the vehicle cannot be pulled over
and must be shut off while driving,
press and hold ENGINE START/STOP
for longer than two seconds, or press
twice in five seconds.
ACC/ACCESSORY (Amber Indicator
Light) :
This mode allows you to use
some electrical accessories when the
engine is off.
With the ignition off, pressing
ENGINE START/STOP once without
the brake pedal applied will place the
ignition system in ACC/ACCESSORY.
The ignition will switch from ACC/
ACCESSORY to OFF after 10 minutes
to prevent battery rundown.
ON/RUN/START (Green Indicator
Light) : This mode is for driving and
starting. With the ignition off and the
brake pedal applied, pressing ENGINE
START/STOP once will place the
ignition system in ON/RUN/START.
Once engine cranking begins, release
the button. Engine cranking will
continue until the engine starts, and
the ignition will then remain ON. See
Starting the Engine 0233. 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.
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).

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
234 DRIVING AND OPERATING
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 Equipment0301.
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 07.
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 the
accelerator pedal all the way to the
floor and hold it there, then press
ENGINE START/STOP for up to a
maximum of 15 seconds. Wait at
least 15 seconds between each try,
to allow the cranking motor to cool
down. When the engine starts, let go of the button and the
accelerator. If the vehicle starts
briefly but then stops again, do the
same thing. This clears the extra
gasoline from the engine. Do not
race the engine immediately after
starting it. Operate the engine and
transmission gently until the oil
warms up and lubricates all
moving parts.
Stop/Start System
This vehicle has a Stop/Start system
to shut off the engine to help
conserve fuel. It has components
designed for the increased number of
starts.
{Warning
The automatic engine Stop/Start
feature causes the engine to shut
off while the vehicle is still on. Do
not exit the vehicle before shifting
to P (Park). The vehicle may restart
and move unexpectedly. Always
shift to P (Park), and then turn the
ignition off before exiting the
vehicle.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 235
Auto Engine Stop/Start
When the brakes are applied and the
vehicle is at a complete stop, the
engine may turn off. When stopped,
the tachometer displays AUTO STOP.
SeeTachometer 0112. When the brake
pedal is released or the accelerator
pedal is pressed, the engine will
restart.
To maintain vehicle performance,
other conditions may cause the engine
to automatically restart before the
brake pedal is released.
Auto Stops may not occur and/or auto
restarts may occur because:
.The climate control settings require
the engine to be running to cool or
heat the vehicle interior.
.The vehicle battery charge is low.
.The vehicle battery has recently
been disconnected.
.Minimum vehicle speed has not
been reached since the last
Auto Stop.
.The accelerator pedal is pressed.
.The engine or transmission is not at
the required operating temperature.
.The outside temperature is not in
the required operating range.
.The vehicle transmission is shifted
out of D (Drive) to any gear other
than P (Park).
.Tow/Haul Mode or other driver
modes have been selected.
.The vehicle is on a steep hill or
grade.
.The driver door has been opened or
the driver seat belt has been
unbuckled.
.The hood has been opened.
.The Auto Stop has reached the
maximum allowed time. Auto Stop Disable Switch
The automatic engine Stop/Start
feature can be disabled and enabled
by touching the
hsymbol. Auto Stop
is enabled each time you start the
vehicle.
When the light next to the
his
illuminated, the system is enabled.
Engine Heater
The engine heater, if available, can
help in cold weather conditions at or
below −18 °C (0 °F) for easier starting
and better fuel economy during
engine warm-up. Plug in the engine
heater at least four hours before

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
236 DRIVING AND OPERATING
starting the vehicle. An internal
thermostat in the plug end of the cord
will prevent engine heater operation
at temperatures above−18 °C (0 °F).
{Warning
Do not plug in the engine block
heater while the vehicle is parked in
a garage or under a carport.
Property damage or personal injury
may result. Always park the vehicle
in a clear open area away from
buildings or structures.
To Use the Engine Heater
1. Turn off the engine.
2. Remove the engine heater
connector cover by gently prying
with a flat-bladed tool at the
location of the notch along the top
edge of the cover.
3. Check the heater cord for damage.If it is damaged, do not use it. See
your dealer for a replacement.
Inspect the cord for damage yearly.
4. Plug the heater cord into theconnector in the front fascia.
5. Plug it into a normal, grounded 110-volt AC outlet.
{Warning
Improper use of the heater cord or
an extension cord can damage the
cord and may result in overheating
and fire.
.Plug the cord into a three-prong
electrical utility receptacle that is
protected by a ground fault
(Continued)

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 237
Warning (Continued)
detection function. An
ungrounded outlet could cause
an electric shock.
.Use a weatherproof, heavy-duty,
15 amp-rated extension cord if
needed. Failure to use the
recommended extension cord in
good operating condition,
or using a damaged heater or
extension cord, could make it
overheat and cause a fire,
property damage, electric shock,
and injury.
.Do not operate the vehicle with
the heater cord permanently
attached to the vehicle. Possible
heater cord and thermostat
damage could occur.
.While in use, do not let the
heater cord touch vehicle parts
or sharp edges.
.Before starting the vehicle,
unplug the cord. Keep the cord
away from any moving parts.
6. Before starting the engine, be sure to unplug and store the cord. 7. Install the engine heater connector
cover.
The length of time the heater should
remain plugged in depends on several
factors. Ask a dealer in the area where
you will be parking the vehicle for the
best advice on this.
Retained Accessory
Power (RAP)
When the ignition is turned from on
to off, the following features (if
equipped) will continue to function
for up to 10 minutes, or until the
driver door is opened. These features
will also work when the ignition is in
RUN or ACC/ACCESSORY:
.Infotainment System
.Power Windows (during RAP this
functionality will be lost when any
door is opened)
.Sunroof (during RAP this
functionality will be lost when any
door is opened)
.Auxiliary Power Outlet
.Audio System
.OnStar System
Shifting Into Park
To shift into P (Park): 1. Hold the brake pedal down and set the parking brake. See Electric
Parking Brake 0246.
2. Press the button on top of the shift lever to shift into P (Park). See
Automatic Transmission 0240.
3. The P indicator on the shift lever will turn red when the vehicle is in
P (Park).
Leaving the Vehicle with the
Engine Running
{Warning
It can be dangerous to leave the
vehicle with the engine running.
It could overheat and catch fire.
It is dangerous to get out of the
vehicle if the vehicle is not in
P (Park) with the parking brake set.
The vehicle can roll.
Do not leave the vehicle when the
engine is running. If you have left
the engine running, the vehicle can
(Continued)

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
238 DRIVING AND OPERATING
Warning (Continued)
move suddenly. You or others could
be injured. To be sure the vehicle
will not move, even when you are
on fairly level ground, always set
the parking brake and shift to
P (Park). SeeShifting Into Park 0237
. If you are towing a trailer, see
Driving Characteristics and Towing
Tips 0290.
If you have to leave the vehicle with
the engine running, be sure the
vehicle is in P (Park) and the parking
brake is set before you leave it.
If you are towing a trailer and parking
on a hill, see Driving Characteristics
and Towing Tips 0290.
Shifting out of Park
This vehicle is equipped with an
electronic transmission. The shift lock
release button is designed to prevent
inadvertent shifting out of P (Park).
To shift out of P (Park):
1. Ensure the engine is running.
2. Apply the brake pedal. 3. Press and hold the shift lock
release button on the shift lever.
4. Move the shift lever to the desired position. For N (Neutral) hold the
lever in the N (Neutral) position
until the N indicator
illuminates red.
5. The P indicator will turn white and the gear indicator will turn red
when the vehicle is no longer in
P (Park).
After releasing the shift lever, it will
return to the center position.
If the vehicle cannot shift from
P (Park), a Driver Information Center
(DIC) message may be displayed.
Check that the ignition is on, the
engine is running, the brake pedal is
applied, and the shift lock release
button is pressed when you are
attempting to shift out of P (park).
If all of these are met but the vehicle
will not shift out of P (Park), see your
dealer for service.
Parking over Things
That Burn
{Warning
Things that can burn could touch
hot exhaust parts under the vehicle
and ignite. Do not park over papers,
leaves, dry grass, or other things
that can burn.
Active Fuel Management
This vehicle's engine may be equipped
with Active Fuel Management, which
allows the engine to operate on either
all of its cylinders, or in reduced
cylinder operation mode, depending
on the driving conditions.
When less power is required, such as
cruising at a constant vehicle speed,
the system will operate in reduced
cylinder operation mode, allowing the
vehicle to achieve better fuel economy.
When greater power demands are
required, such as accelerating from a
stop, passing, or merging onto a
freeway, the system will maintain
full-cylinder operation.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 239
If the vehicle has an Active Fuel
Management indicator, see Driver
Information Center (DIC) for more
information on using this display.
Extended Parking
It is best not to park with the vehicle
running. If the vehicle is left running,
be sure it will not move and there is
adequate ventilation.
SeeShifting Into Park 0237 and
Engine Exhaust 0239.
If the vehicle is left parked and
running with the RKE transmitter
outside the vehicle, it will continue to
run for up to half an hour.
If the vehicle is left parked and
running with the RKE transmitter
inside the vehicle, it will continue to
run for up to an hour.
The vehicle could turn off sooner if it
is parked on a hill, due to lack of
available fuel.
The timer will reset if the vehicle is
taken out of P (Park) while it is
running.
Engine Exhaust
{
Warning
Engine exhaust contains carbon
monoxide (CO), which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas with
poor ventilation (parking garages,
tunnels, deep snow that may
block underbody airf low or tail
pipes).
.The exhaust smells or sounds
strange or different.
.The exhaust system leaks due to
corrosion or damage.
.The vehicle exhaust system has
been modified, damaged,
or improperly repaired.
.There are holes or openings in
the vehicle body from damage or
aftermarket modifications that
are not completely sealed. (Continued)
Warning (Continued)
If unusual fumes are detected or if
it is suspected that exhaust is
coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed area
such as a garage or a building that
has no fresh air ventilation.
Running the Vehicle While
Parked
It is better not to park with the engine
running.
If the vehicle is left with the engine
running, follow the proper steps to be
sure the vehicle will not move. See
Shifting Into Park 0237 and
Engine Exhaust 0239.
If parking on a hill and pulling a
trailer, see Driving Characteristics and
Towing Tips 0290.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
240 DRIVING AND OPERATING
Automatic Transmission
The shift pattern is displayed in the
top of the shift lever. The selected
gear position will illuminate red on
the shift lever, while all others will be
displayed in white. If the shift is not
immediate, as in very cold conditions,
the indicator on the shift lever may
flash until it is fully engaged.
The shift lever always starts from a
center position, represented by an up/
down arrow on the shift pattern. After
releasing the shift lever, it will return
to the center position.
The transmission does not operate
when the vehicle is off.If the vehicle is in ACC/ACCESSORY,
the transmission can be shifted into
P (Park).
If the vehicle is turned off while at a
relatively high vehicle speed, the
transmission will automatically shift
to N (Neutral). Once the vehicle is
stopped, P (Park) is automatically
selected.
P :
This position locks the drive
wheels. Use P (Park) when starting the
engine because the vehicle cannot
move easily.
{Warning
It is dangerous to get out of the
vehicle if the transmission is not in
P (Park) with the parking brake set.
The vehicle can roll.
Do not leave the vehicle when the
engine is running. If the engine has
been left running, the vehicle can
move suddenly. You or others could
be injured. To be sure the vehicle
will not move, even when on fairly
level ground, always set the parking
brake and place the transmission
into P (Park). See Shifting Into Park
0 237 and
Electric Parking Brake 0246.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 241
This vehicle is equipped with an
electronically controlled transmission.
The shift lock release button is
designed to prevent inadvertent
shifting out of P (Park) unless the
ignition is on, the brake pedal is
applied, and the shift lock release
button is pressed.
When the vehicle is stopped, press
ENGINE START/STOP to turn off the
vehicle. The transmission will shift to
P (Park) automatically unless the
vehicle is in N (Neutral), See“Car
Wash Mode ”later in this section.
The vehicle will not shift into P (Park)
if it is moving too fast. Stop the
vehicle and shift into P (Park). To shift into and out of P (Park), see
Shifting Into Park
0237 and
Shifting out of Park 0238.
Service Shift Lever Message
If the message SERVICE SHIFTER SEE
OWNER’S MANUAL appears in the
Driver Information Center (DIC), the
shift lever needs service. Have the
vehicle serviced as soon as possible.
If the vehicle is automatically shifting
into P (Park), check to see if the
P (Park) button on top of the shift
lever is stuck. To operate the vehicle,
hold the shift lever in the desired gear,
R (Reverse) or D (Drive), until vehicle
speed exceeds 15 km/h (10 mph), then
release the shift lever.
R : Use this gear to back up.
If the vehicle is shifted from either
R (Reverse) to D (Drive) or M (Manual
Mode), or M (Manual Mode) or
D (Drive) to R (Reverse) while the
speed is too high, the vehicle will shift
to N (Neutral). Reduce the vehicle
speed and try the shift again.
To shift into R (Reverse): 1. Bring the vehicle to a complete stop. 2. Press and hold the shift lock
release button on the side of the
shift lever.
3. From the center position, move the shift lever forward through the first
detent to the end of travel. R is
illuminated in red.
4. After releasing the shift lever, it will return to the center position.
To shift out of R (Reverse): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
3. After releasing the shift lever, it will return to the center position.
At low vehicle speeds, R (Reverse) can
be used to rock the vehicle back and
forth to get out of snow, ice, or sand
without damaging the transmission.
See If the Vehicle Is Stuck 0228.
N : In this position, the engine does
not connect with the wheels. To
restart the engine when the vehicle is
already moving, use N (Neutral) only.