2023 CADILLAC CT4 ECU

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/10/22
360 Driving and Operating
If equipped, the following
driver assistance features
should be turned to alert or
off when towing a trailer:
.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.
.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 0271.
Towing a trailer requires
experience. The combination
of the vehicle and trailer is
longer and not as responsive
as the vehicle itself. Become
familiar with handling and braking 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
0365. If the trailer
has electric brakes, start the
combination moving and then
manually apply the trailer
brake controller to check 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.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
390 Vehicle Care
To use this feature:
1. With a cold system, addcoolant to the indicated
line on the surge tank.
2. Replace the pressure cap on the surge tank.
3. Activate the service feature:
3.1. Connect the vehicle to a battery charger.
3.2.Turn the ignition to Service Mode. See
Ignition Positions 0261.
3.3.Turn off the air conditioning. 3.4.Set the parking brake.
3.5.At the same time, press
the accelerator and the
brake pedal for
two seconds, then
release.
3.6.At the end of the cycle, check the coolant level
in the surge tank and
add coolant if it is
below the indicated
line. Turn the ignition
off, allow the Electronic
Control Module (ECM)
to go to sleep, about
two minutes, and
repeat Steps 3.2 –3.6.
Listen for pump activation and
movement of the control
valves while watching the level
of the coolant in the surge
tank. If the tank empties, turn
the ignition off, carefully
remove the pressure cap, refill
to the indicated line, replace
the pressure cap, and repeat
steps 3.2 –3.6. The fill and air removal
process will run for
approximately 15 minutes.
Caution
If the pressure cap is not
tightly installed, coolant loss
and engine damage may
occur. Be sure the cap is
properly and tightly secured.
2.7L L4 Engine
Automatic Coolant Service
Fill Instructions
The vehicle is equipped with a
service feature that assists
with filling and removing air
from the cooling system after
service of components or
when coolant is added after
being to low.
To use this feature:
1. With a cold system unscrew the cooling
system air bleeder cap.
If coolant can be seen
through the bleeder move
to Step 3.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
Vehicle Care 391
2. Add coolant through thesurge tank until it is visible
through the air bleeder.
3. Replace the cooling system air bleeder cap.
4. Add coolant to the indicated line on the
surge tank.
5. Replace the pressure cap on the surge tank.
6. Activate the service feature:
6.1. Connect the vehicle to a battery charger.
6.2.Turn the ignition to Service Mode. See
Ignition Positions 0261.
6.3.Turn off the air conditioning.
6.4.Set the parking brake.
6.5.At the same time, press the accelerator and the
brake pedal for
two seconds, then
release. 6.6.At the end of the cycle,
check the coolant level
in the surge tank and
add coolant if it is
below the indicated
line. Turn the ignition
off, carefully remove
the pressure cap, refill
to the indicated line,
replace the pressure
cap, and repeat steps
6.2 –6.6.
Listen for pump activation and
movement of the control
valves while watching the level
of the coolant in the surge
tank. If the tank empties, turn
the ignition off, carefully
remove the pressure cap, refill
to the indicated line, replace
the pressure cap, and repeat
steps 6.2 –6.6.
The fill and air removal
process will run for
approximately 15 minutes.Caution
If the pressure cap is not
tightly installed, coolant loss
and engine damage may
occur. Be sure the cap is
properly and tightly secured.
Engine Overheating
The vehicle has an indicator to
warn of the engine
overheating.
If the decision is made not to
lift the hood when this
warning appears, get service
help right away. See Roadside
Assistance Program 0487.
If the decision is made to lift
the hood, make sure the
vehicle is parked on a level
surface.
Then check to see if the
engine cooling fan is running.
If the engine is overheating,
the fan should be running. If it
is not, do not continue to run
the engine. Have the vehicle
serviced.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
Vehicle Care 437
Tire Chains
{Warning
If the vehicle has
235/40R18, 235/35R19,
255/35ZR18, or
275/35ZR18 size tires, do
not use tire chains. There is
not enough clearance. Tire
chains used on a vehicle
without the proper amount
of clearance can cause
damage to the brakes,
suspension, or other vehicle
parts. The area damaged by
the tire chains could cause
loss of control and a crash.
Use another type of traction
device only if its
manufacturer recommends
it for the vehicle's tire size
combination and road
conditions. Follow that
manufacturer's instructions.
To avoid vehicle damage,
drive slow and readjust or
remove the traction device if(Continued)
Warning (Continued)
it contacts the vehicle. Do
not spin the wheels.
If traction devices are used,
install them on the rear tires.
Caution
If the vehicle is equipped
with a tire size other than
235/40R18, 235/35R19,
255/35ZR18, or
275/35ZR18, use tire chains
only where legal and only
when necessary. Use low
profile chains that add no
more than 12 mm thickness
to the tire tread and inner
sidewall. Use chains that are
the proper size for the tires.
Install them on the tires of
the rear axle. Don't use
chains on the tires of the
front axle. Tighten them as
tightly as possible with the
ends securely fastened.
Drive slowly and follow the(Continued)
Caution (Continued)
chain manufacturer's
instructions. If the chains
contact the vehicle, stop and
retighten them. If the
contact continues, slow
down until it stops. Driving
too fast or spinning the
wheels with chains on will
damage the vehicle.
If a Tire Goes Flat
It is unusual for a tire to blow
out while driving, especially if
the tires are maintained
properly. If air goes out of a
tire, it is much more likely to
leak out slowly. See Tires
0413 for additional
information. But if there ever
is a blowout, here are a few
tips about what to expect and
what to do:
If a front tire fails, the flat tire
creates a drag that pulls the
vehicle toward that side. Take
your foot off the accelerator
pedal and grip the steering

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
450 Vehicle Care
After starting the disabled
vehicle and removing the
jumper cables, allow it to idle
for several minutes.
Towing the
Vehicle
Transporting a
Disabled Vehicle
(Electronic Shifter)
Caution
Incorrectly transporting a
disabled vehicle may cause
damage to the vehicle. Use
proper tire straps to secure
the vehicle to the flatbed
tow truck. Do not strap or
hook to any frame,
underbody, or suspension
component not specified
below. Do not move vehicles
with drive axle tires on the
ground. Damage is not
covered by the vehicle
warranty.
Caution
The vehicle may be equipped
with an electric parking
brake and/or an electronic
shifter. In the event of a loss
of 12-volt battery power, the
electric parking brake
cannot be released, and the
vehicle cannot be shifted to
N (Neutral). Tire skates or
dollies must be used under
the non-rolling tires to
prevent damage while
loading/unloading the
vehicle. Dragging the vehicle
will cause damage not
covered by the vehicle
warranty.
Caution
The vehicle may be equipped
with a tow eye. Improper use
of the tow eye may cause
damage to the vehicle and is
not covered by the vehicle
warranty. If equipped, use(Continued)
Caution (Continued)
the tow eye to load the
vehicle onto a flatbed tow
truck from a flat road
surface, or to move the
vehicle a very short distance
at a walking pace. The tow
eye is not designed for
off-road recovery. The
vehicle must be in
N (Neutral) with the electric
parking brake released when
using the tow eye.
Contact a professional towing
service if the disabled vehicle
must be transported. GM
recommends a flatbed tow
truck to transport a disabled
vehicle. Use ramps to help
reduce approach angles,
if necessary.
If equipped, a tow eye may be
located near the spare tire or
emergency jack. Do not use
the tow eye to pull the vehicle
from the snow, mud, sand,
or ditch. Tow eye threads may

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
452 Vehicle Care
Install the tow eye into the
socket and turn it until it is
fully tightened. When the tow
eye is removed, reinstall the
cover with the notch in the
original position.
Rear Tow Eye
If equipped, carefully open the
cover by using the small notch
that conceals the rear tow eye
socket. Install the tow eye into
the socket and turn it until it is
fully tightened. When the tow
eye is removed, reinstall the
cover with the notch in the
original position.
Transporting a
Disabled Vehicle
(Mechanical Shifter)
Caution
Incorrectly transporting a
disabled vehicle may cause
damage to the vehicle. Use
proper tire straps to secure
the vehicle to the flatbed
tow truck. Do not strap or
hook to any frame,
underbody, or suspension
component not specified
below. Do not move vehicles
with drive axle tires on the
ground. Damage is not
covered by the vehicle
warranty.
Caution
The vehicle may be equipped
with an electric parking
brake and/or a mechanical
transmission range select
shifter. In the event of a loss(Continued)
Caution (Continued)
of 12-volt battery power, the
electric parking brake
cannot be released, and the
vehicle cannot be shifted to
N (Neutral). Tire skates or
dollies must be used under
the non-rolling tires to
prevent damage while
loading/unloading the
vehicle. Dragging the vehicle
will cause damage not
covered by the vehicle
warranty.
Caution
The vehicle may be equipped
with a tow eye. Improper use
of the tow eye may cause
damage to the vehicle and is
not covered by the vehicle
warranty. If equipped, use
the tow eye to load the
vehicle onto a flatbed tow
truck from a flat road
surface, or to move the(Continued)

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
Vehicle Care 465
{Warning
Do not bleach or dye seat
belt webbing. It may severely
weaken the webbing. In a
crash, they might not be
able to provide adequate
protection. Clean and rinse
seat belt webbing only with
mild soap and lukewarm
water. Allow the webbing
to dry.
Floor Mats
{Warning
If a floor mat is the wrong
size or is not properly
installed, it can interfere
with the pedals. Interference
with the pedals can cause
unintended acceleration
and/or increased stopping
distance which can cause a
crash and injury. Make sure
the floor mat does not
interfere with the pedals.Use the following guidelines
for proper floor mat use.
.The original equipment floor
mats are designed for your
vehicle. If the floor mats
need to be replaced, it is
recommended that
GM-certified floor mats are
purchased. Non-GM floor
mats may not fit properly
and may interfere with the
pedals. Always check that
the floor mats do not
interfere with the pedals.
.Do not use a floor mat if the
vehicle is not equipped with
a floor mat retainer on the
driver side floor.
.Use the floor mat with the
correct side up. Do not turn
it over.
.Do not place anything on top
of the driver side floor mat.
.Use only a single floor mat
on the driver side.
.Do not place one floor mat
on top of another.
The floor mats are held in
place by button-type retainers.
Removing and Replacing
the Floor Mats
1. Pull up on the rear of the floor mat to unlock the
retainers and remove.
2. Reinstall by lining up the floor mat retainer openings
over the carpet retainers
and snap into position.
3. Make sure the floor mat is properly secured in place.
Verify the floor mat does
not interfere with the
pedals.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-16500442) -
2023 - CRC - 5/4/22
Service and Maintenance 471
Severe Conditions
Requiring More Frequent
Maintenance*
.Public service, military,
or commercial use vehicles
to include the following:
‐Ambulances, police cars,
and emergency rescue
vehicles.
‐ Civilian vehicles such as
light duty pick-up trucks,
SUVs, and passenger cars
that are used in military
applications.
‐ Recovery vehicles such as
tow trucks and flatbed
single vehicle carriers or
any vehicle that is
consistently used in towing
trailers or other loads.
‐ High use commercial
vehicles such as courier
delivery vehicles, private
security patrol vehicles,
or any vehicles that
operate on a 24–hour
basis. ‐
Any vehicle consistently
operated in a high sand or
dust environment such as
those used on oil pipelines
and similar applications.
.Vehicles that are regularly
used for short trips of 6 km
(4 mi) or less.
The oil life indicator will show
you when to change the oil
and filter. Under severe
conditions the indicator may
come on before 12 000 km
(7,500 mi).
* Footnote: Under extreme
driving conditions listed
above, it may be necessary
to replace your spark plugs
at more frequent intervals.
For further assistance in
determining the most
suitable service maintenance
intervals for your vehicle,
please contact your
authorized GM Dealer. Extreme service is for
vehicles mainly driven
off-road in four-wheel drive
or used in farming, mining,
forestry, or snow plowing.Additional Required
Services
—Severe Service
Every 72 000 km (45,000 mi)
.Change automatic
transmission fluid and filter.
.Change transfer case fluid,
if equipped with AWD. Do
not directly power wash the
transfer case and/or front/
rear axle output seals. High
pressure water can
overcome the seals and
contaminate the transfer
case fluid. Contaminated
fluid will decrease the life of
the transfer case and/or
axles and should be
replaced.
.Change rear axle fluid, with
limited slip differential. Do
not directly power wash the
transfer case and/or front/
rear axle output seals. High