engine CADILLAC CT6 2018 1.G Repair Manual

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
226 DRIVING AND OPERATING
Extended Parking
It is better not to park with the
vehicle running. If the vehicle is left
while running, follow the proper steps
to be sure the vehicle will not move
and there is adequate ventilation.
SeeShifting Into Park 0224 and Engine
Exhaust 0230.
If the vehicle is left parked while
running and the Remote Keyless
Entry (RKE) transmitter is outside the
vehicle, the vehicle will turn off after
one hour. If the vehicle is left parked
while running and the RKE
transmitter is inside, the vehicle will
turn off after two hours.
The timer will reset if the vehicle is
taken out of P (Park) while it is
running.
Electric Vehicle
Operating Modes
Driver Selected Operating
Modes (PLUG-IN Only)
For gasoline only engines see Driver
Mode Control (Gasoline Only) 0241.
While driving with PLUG-IN or
gasoline propulsion, additional
operating modes can be selected.
Press MODE to display selectable drive
modes in the Driver Information
Center (DIC). Continue pressing to
scroll through the modes. During some conditions, certain drive
modes may be unavailable. The
unavailable mode is grayed out in the
DIC menu and cannot be selected.
Tour
Mode
The vehicle is in Tour Mode when the
menu item Tour is selected. Use Tour
Mode whenever possible. Each time
the vehicle is started it will start in
Tour Mode.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
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DRIVING AND OPERATING 227
SportMode
Sport Mode provides more responsive
acceleration than Tour Mode, but can
reduce efficiency. Use Tour Mode
whenever possible.
During some conditions, certain drive
modes may be unavailable. The
unavailable mode is grayed out in the
DIC menu and cannot be selected.
If in Sport or Hold Mode, the mode
may become unavailable and the
vehicle will return to Tour Mode. The
indicator light goes off and a DIC
message displays.
Press MODE to select Sport Mode. Press MODE again to return to Tour
Mode and it becomes active after
three seconds.
Hold
Mode
Use Hold Mode on a trip where it is
expected that all of the electric charge
will be depleted. Use Hold Mode
mainly during highway or high speed
driving to maximize both PLUG-IN
propulsion miles and fuel efficiency.
This mode places the remaining
battery charge into a reserve for the
driver to use as desired. Selecting this
mode transitions the vehicle to
gasoline propulsion to maintain the battery charge reserve. The reserve
battery charge will appear grayed out
while in this mode.
Upon exiting Hold Mode, the reserved
battery charge becomes available
again and the vehicle returns to
PLUG-IN propulsion.
Hold Mode will not change normal
vehicle acceleration or braking
performance.
Press MODE to select Hold Mode.
Press MODE again to return to Tour
Mode and it becomes active after
three seconds.
Out of Fuel/Engine
Unavailable
If the vehicle runs out of fuel, or the
engine will not start due to a
malfunction, the vehicle can continue
to be driven with electric propulsion
until the current charge is depleted.
The vehicle will have less responsive
acceleration. DIC messages indicate
reduced propulsion power, that the
engine is not available, and the need
for fuel or service.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
228 DRIVING AND OPERATING
Once the vehicle is refueled, or the
malfunction is corrected, the engine
will start the next time the vehicle is
turned on to perform a self test, and
DIC messages will not be displayed.
Once the engine starts successfully,
normal operation will continue with
either electric propulsion or with the
engine running. The engine will stop
running after the self test is
completed, and based on the current
mode of operation.
Maintenance Modes
Engine Maintenance Mode (EMM)
EMM runs the engine to keep it in
good working condition after
approximately six weeks of no or very
limited engine operation. EMM will
force the engine to run, even if there
is a charge to power the vehicle.
When EMM is needed, the EMM
Request screen appears on the
infotainment display at vehicle start.
If Yes is selected, EMM will begin. The
engine will not start until after a short
delay once shifted into D (Drive). The
engine will run for a set amount of
time without turning off. During
EMM, a DIC message displays to show
the EMM percentage complete.
If No is selected, the EMM Request
screen will appear when the vehicle is
next started. The EMM request can be
delayed for up to one day.
If the EMM request was delayed for
one day, EMM will automatically start
the engine at the next vehicle start.
The engine will not start until after a
short delay once shifted into D (Drive).An EMM Notification screen will
appear in the infotainment display.
If the vehicle is shut off during EMM,
it will restart the next time the vehicle
is driven.
A message displays to indicate that
EMM is active.
If EMM is required and the fuel level
is low, EMM may eventually empty
the fuel tank if fuel is not added. This

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
DRIVING AND OPERATING 229
will result in reduced, or no power. An
adequate fuel level must be
maintained in the vehicle to keep it
operational.
Fuel Maintenance Mode (FMM)
FMM tracks average fuel age. Old fuel
can cause engine problems. If low
engine usage causes average fuel age
to exceed approximately one year,
FMM will run the engine to use up
the old fuel. The engine will run until
enough fresh fuel is added to bring
the average fuel age into an
acceptable range. Allowing more old
fuel to be used up by FMM and
adding a larger amount of fresh fuel
will maximize the length of time
before another fuel maintenance
mode is needed. During FMM the
engine may turn on and off.
When FMM is needed, the FMM
Request screen appears on the
infotainment display at vehicle start.
If Yes is selected, FMM will begin. The
engine will not start until after a short
delay once shifted into D (Drive). FMM
will automatically continue at each
vehicle start until fresh fuel is added.
If No is selected, the FMM Request
screen will appear when the vehicle is
next started. The FMM request can be
delayed for only one day.If the FMM request was delayed for
one day, FMM will start at the next
vehicle start and display the FMM
Notification screen on the
infotainment display. The engine will
not start until after a short delay once
shifted into D (Drive).
If FMM is required and the fuel level
is low, FMM may eventually empty
the fuel tank if fuel is not added. This
will result in reduced, or no power. An
adequate fuel level must be
maintained in the vehicle to keep it
operational. After FMM has run it is
recommended to fill the fuel tank.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
230 DRIVING AND OPERATING
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
airflow 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.
(Continued)
Warning (Continued)
.There are holes or openings
in the vehicle body from
damage or aftermarket
modifications that are not
completely sealed.
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 0224 and Engine
Exhaust 0230.
If parking on a hill and pulling a
trailer, see Driving Characteristics and
Towing Tips 0290.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
DRIVING AND OPERATING 231
Automatic Transmission
There are several different positions
for the shift lever.
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 shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
(Continued)
Warning (Continued)
Do not leave the vehicle when the
engine is running unless you have
to. If you have left the engine
running, the vehicle can 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 move the shift
lever to P (Park). SeeShifting Into
Park 0224. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips 0290.
Make sure the shift lever is fully in
P (Park) before starting the engine.
The vehicle has an electronic shift
lock release system. Fully apply the
regular brakes first and then press the
shift lever button before shifting from
P (Park) when the ignition is on. If you
cannot shift out of P (Park), ease
pressure on the shift lever and push
the shift lever all the way into P (Park)
as you maintain brake application. Then press the shift lever button and
move the shift lever into another gear.
See
Shifting out of Park 0225.
Caution
Shifting to R (Reverse) while the
vehicle is moving forward could
damage the transmission. The
repairs would not be covered by the
vehicle warranty. Shift to
R (Reverse) only after the vehicle is
stopped.
R : Use this gear to back up.
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 0212.
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.
You can also use N (Neutral) when the
vehicle is being towed.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
232 DRIVING AND OPERATING
{Warning
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift into
a drive gear while the engine is
running at high speed.
Caution
Shifting out of P (Park) or
N (Neutral) with the engine running
at high speed may damage the
transmission. The repairs would not
be covered by the vehicle warranty.
Be sure the engine is not running at
high speed when shifting the
vehicle.
Caution
A transmission hot message may
display if the automatic
transmission fluid is too hot.
Driving under this condition can
damage the vehicle. Stop and idle
the engine to cool the automatic
transmission fluid. This message
clears when the transmission fluid
has cooled sufficiently.
D : This position is for normal driving.
If more power is needed for passing,
press the accelerator pedal down.
Downshifting the transmission in
slippery road conditions could result
in skidding. See “Skidding”underLoss
of Control 0209.
M : This mode can be entered by
moving the shift lever from D (Drive)
to M (Manual Mode). M (Manual
Mode) allows the driver to select gears
appropriate for current driving
conditions. M (Manual Mode) can be
exited by returning the shift lever to
D (Drive). See Manual Mode (Gasoline
Only) 0233. For PLUG-IN vehicles, see
Regenerative
Braking (PLUG-IN Only) 0237.Caution
Spinning the tires or holding the
vehicle in one place on a hill using
only the accelerator pedal may
damage the transmission. The
repair will not be covered by the
vehicle warranty. If the vehicle is
stuck, do not spin the tires. When
stopping on a hill, use the brakes to
hold the vehicle in place.
While in Sport Mode, the vehicle
monitors driving behavior and
automatically enables performance
shift features when spirited driving is
detected. These features maintain
lower transmission gears to increase
available engine braking and improve
acceleration response. The vehicle will
exit these features and return to
normal operation after a short period
when no spirited driving is detected.
See Driver Mode Control (Gasoline Only)
0 241.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
DRIVING AND OPERATING 233
Manual Mode
(Gasoline Only)
For PLUG-IN vehicles, seeRegenerative
Braking (PLUG-IN Only) 0237.
Tap Shift
Caution
Driving with the engine at a high
rpm without upshifting while using
Tap Shift, could damage the vehicle.
Always upshift when necessary
while using Tap Shift.
If equipped, vehicles with Tap Shift
have controls on the back of the
steering wheel to manually shift the
automatic transmission.
To enter Permanent Tap Shift Mode: 1. Move the shift lever from D (Drive) to M (Manual Mode).
While in Tap Shift Mode, the M
on the PRNDM section of the
instrument cluster will become
highlighted, and the current gear
is indicated.
2. Tap the left control toward the driver to downshift, and the right
control toward the driver to
upshift. To shift to the lowest
available gear, press and hold the
left control.
3. To exit, move the shift lever back to D (Drive).
With the shift lever in D (Drive) and
not in Permanent Tap Shift Mode, the
Tap Shift controls will activate a
temporary tap manual shift mode,
allowing the transmission to be
manually shifted. The vehicle exits
Temporary Tap Shift Mode after the
accelerator pedal is steady for six seconds. Temporary Tap Shift
Mode holds a gear longer without
exiting when coasting, to provide
powertrain braking. The Temporary
Tap Shift Mode can also be
deactivated by holding the right
upshift control briefly.
While using Tap Shift, the vehicle will
have firmer, quicker shifting. You can
use this for sport driving or when
climbing or descending hills, to stay in
gear longer, or to downshift for more
power or engine braking.
The transmission will only allow you
to shift into gears appropriate for the
vehicle speed and engine revolutions
per minute (rpm). The transmission
will not downshift if the engine rpm is
too high in the next lower gear,
or upshift to the next higher gear
when the maximum engine rpm is
reached.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
234 DRIVING AND OPERATING
If shifting is prevented for any reason,
a SHIFT DENIED message will be
displayed in the instrument cluster.
When accelerating the vehicle from a
stop in snowy and icy conditions, it is
suggested to shift into second gear.
A higher gear allows the vehicle to
gain more traction on slippery
surfaces.Drive Systems
All-Wheel Drive
Vehicles with this feature always send
engine power to all four wheels. It is
fully automatic, and adjusts itself as
needed for road conditions.
Brakes
Antilock Brake
System (ABS)
This vehicle has an Antilock Brake
System (ABS), an advanced electronic
braking system that helps prevent a
braking skid.
When the vehicle begins to drive
away, ABS checks itself. A momentary
motor or clicking noise may be heard
while this test is going on, and it may
even be noticed that the brake pedal
moves a little. This is normal.
If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
0 146.
If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to avoid

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
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DRIVING AND OPERATING 235
a sudden obstacle, a computer senses
the wheels are slowing down. If one of
the wheels is about to stop rolling, the
computer will separately work the
brakes at each wheel.
ABS can change the brake pressure to
each wheel, as required, faster than
any driver could. This can help you
steer around the obstacle while
braking hard.
As the brakes are applied, the
computer keeps receiving updates on
wheel speed and controls braking
pressure accordingly.
Remember: ABS does not change the
time needed to get a foot up to the
brake pedal or always decrease
stopping distance. If you get too close
to the vehicle in front of you, there
will not be enough time to apply the
brakes if that vehicle suddenly slows
or stops. Always leave enough room
up ahead to stop, even with ABS.Using ABS
Do not pump the brakes. Just hold the
brake pedal down firmly and let ABS
work. You may hear the ABS pump or
motor operating and feel the brake
pedal pulsate. This is normal.
Braking in Emergencies
ABS allows you to steer and brake at
the same time. In many emergencies,
steering can help more than even the
very best braking.
Electric Parking Brake
The vehicle has an Electric Parking
Brake (EPB). The EPB can always be
activated, even if the ignition is off. To
prevent draining the battery, avoid
repeated cycles of the EPB system
when the engine is not running.
The system has a
Yor PARK
Electric Parking Brake light, and a
8
Service Parking Brake light.
See Electric Parking Brake Light 0145
and Service Electric Parking Brake Light
0 146.
Before leaving the vehicle, check for
the
Yor PARK light to ensure that
the parking brake is applied.
EPB Apply
To apply the EPB:
1. Be sure the vehicle is at a complete stop.
2. Press the EPB switch momentarily.
The
Yor PARK light will flash and
then stay on once the EPB is fully
applied. If the
Yor PARK light
flashes continuously, then the EPB is
only partially applied or there is a