2021 CADILLAC CT4 check engine

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
INSTRUMENTS AND CONTROLS 105
This light should come on briefly as
the engine is started. If it does not
come on, have the vehicle serviced by
your dealer.
If the light comes on and stays on, it
means that oil is not flowing through
the engine properly. The vehicle could
be low on oil and might have some
other system problem. See your dealer.
Low Fuel Warning Light
A Low Fuel Warning Light near the
fuel gauge comes on briefly when the
ignition is turned on as a check to
show it is working.It also comes on when the fuel gauge
indicator nears empty. The light turns
off when fuel is added. If it does not,
have the vehicle serviced.
Security Light
The security light should come on
briefly as the engine is started. If it
does not come on, have the vehicle
serviced by your dealer. If the system
is working normally, the indicator
light turns off.
If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent
system. See
Immobilizer Operation
0 23.
High-Beam On Light
This light comes on when the
high-beam headlamps are in use. See
Headlamp High/Low-Beam Changer
0128.
IntelliBeam Light
This light comes on when the
IntelliBeam system, if equipped, is
enabled. See Exterior Lamp Controls
0 126.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
116 INSTRUMENTS AND CONTROLS
Navigation Overlay :This displays
digital speed for Tour/ Sport, current
gear for Track, indicators from speed
view along with Turn-by-Turn
Navigation information in some
vehicles. The compass heading is
displayed when navigation routing is
not active.
Navigation Turn-by-Turn Alerts
shown in the instrument cluster may
also be displayed in any HUD view.
Care of the HUD
Clean the inside of the windshield to
remove any dirt or film that could
reduce the sharpness or clarity of the
HUD image.
Clean the HUD lens with a soft cloth
sprayed with glass cleaner. Wipe the
lens gently, then dry it.
HUD Troubleshooting
If you cannot see the HUD image
when the ignition is on, check that:
.Nothing is covering the HUD lens.
.The HUD brightness setting is not
too dim or too bright.
.The HUD is adjusted to the proper
height.
.Polarized sunglasses are not worn.
.The windshield and HUD lens are
clean.
If the HUD image is not correct,
contact your dealer.
The windshield is part of the HUD
system. If windshield replacement is
required, see Windshield Replacement
0 328.
Vehicle Messages
Messages displayed on the Driver
Information Center (DIC) indicate the
status of the vehicle or some action
that may be needed to correct a
condition. Multiple messages may
appear one after another.
The messages that do not require
immediate action can be
acknowledged and cleared by pressing
the thumbwheel. The messages that
require immediate action cannot be
cleared until that action is performed.
All messages should be taken
seriously; clearing the message does
not correct the problem. If a SERVICE message appears, see
your dealer.
Follow the instructions given in the
messages. The system displays
messages regarding the following
topics:
.Service Messages
.Fluid Levels
.Vehicle Security
.Brakes
.Steering
.Ride Control Systems
.Driver Assistance Systems
.Cruise Control
.Lighting and Bulb Replacement
.Wiper/Washer Systems
.Doors and Windows
.Seat Belts
.Airbag Systems
.Engine and Transmission
.Tire Pressure
.Battery

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
DRIVING AND OPERATING 207
Track Events and
Competitive Driving
(V-Series Only)
{Danger
High-performance features are
intended for use only on closed
tracks by experienced and qualified
drivers and should not be used on
public roads. High-speed driving,
aggressive cornering, hard braking,
and other high-performance driving
can be dangerous. Improper driver
inputs for the conditions may result
in loss of control of the vehicle,
which could injure or kill you or
others. Always drive safely.
Track events and competitive driving
may affect the vehicle warranty. See
the warranty manual before using the
vehicle for competitive driving.
{Warning
Prior to each track event and again
before returning to public roads,
tighten the wheel nuts with a
torque wrench to the proper torque
specification. Wheel nuts that are
improperly or incorrectly tightened
can cause the wheels to become
loose or come off, resulting in a
crash. See Capacities and
Specifications 0396 for wheel nut
torque specifications.
Caution
Low oil levels can damage the
engine. If using the vehicle for
competitive driving, the engine may
use more oil than it would with
normal use. Check the oil level
often during competitive driving.
Competitive Driving Mode can be
selected. See Driver Mode Control
0 241.
Axle Fluid
Axles must have 2400 km (1500 mi)
before being used in track driving.
The rear axle fluid temperatures may
be higher than when driving in severe
conditions. Drain and refill with new
fluid after the first racing or
competitive driving event, and then
after every 24 hours of racing or
competitive driving. See Recommended
Fluids and Lubricants 0391.
Caution
During a first time track or racing
event, high axle temperatures can
occur. Damage could be caused to
the axle and would not be covered
by the vehicle warranty. Do not
drive as long or as fast the first
time the vehicle is driven on the
track or raced.
.The axle lubricant should be
replaced with new lubricant.
.Additional cooling capacity is also
required for continuous competitive
driving.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
208 DRIVING AND OPERATING
Engine Oil
Check the oil level often during track
events and competitive driving and
keep the oil level at or near the
upper mark.
Fuel
Use premium unleaded gasoline with
a posted octane rating of 93 at a track
event. Unleaded gasoline with a
posted octane rating of 91 may be
used, but performance will be
degraded.
Automatic Transmission Fluid
Have the transmission fluid set to the
track specific oil level prior to track
usage. Transmission fluid should be
changed after every 15 hours of track
usage. Any transmission level set or
change should be performed at your
dealer.
Brakes
Brake cooling can be improved if the
front brake disc splash shield and
front tire deflector are removed.
Removing the shield will require that
the suspension bushings and wheelspeed wires visible to the brake disc
be protected with insulated thermal
wrapping.
Caution
Removing the splash shield can
degrade wet braking performance,
as well as introduce brake pedal
pulsation, due to brake disc
exposure to road debris. Only
remove the front brake disc splash
shield and front tire deflector when
driving in track events.
Brake Pad Wear Sensors
(V-Series Only)
If equipped, the brake pad wear
sensors need to be removed from the
brake calipers prior to any track or
racing event. The original sensors can
be reinstalled if significant brake pad
wear is not observed. The sensor
should not extend beyond the brake
pad surface at the rotor contact.
If this condition is observed, the brake
pad life system needs to be disabled
until a new set of brake pads and
sensors are installed and the system
reset. Brake Fluid
.Before racing, replace existing brake
fluid with a qualified racing brake
fluid from a sealed container. Brake
fluid with a dry boiling point
>279 °C (534 °F) is qualified.
If racing brake fluid is used, replace
it with GM approved brake fluid
before driving on public roads. See
Recommended Fluids and Lubricants
0
391.
.Do not use silicone-based fluids.
If racing brake fluid is in the vehicle
and the age of the brake fluid is over a
month old or unknown, replace the
brake fluid between racing/closed
track driving.
Caution
Failure to change the brake fluid
and transfer case fluid after any
performance or race track driving
could result in damage not covered
by the vehicle warranty. Have the
brake fluid and transfer case fluid
changed by your dealer after any (Continued)

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
212 DRIVING AND OPERATING
{Warning
Wet brakes can cause crashes. They
might not work as well in a quick
stop and could cause pulling to one
side. You could lose control of the
vehicle.
After driving through a large puddle
of water or a car/vehicle wash,
lightly apply the brake pedal until
the brakes work normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be very
cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water can
build up under the vehicle's tires so
they actually ride on the water. This
can happen if the road is wet enoughand you are going fast enough. When
the vehicle is hydroplaning, it has
little or no contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping equipment
in good shape.
.Keep the windshield washer fluid
reservoir filled.
.Have good tires with proper tread
depth. See
Tires0339.
.Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving on
flat or rolling terrain. Tips include:
.Keep the vehicle serviced and in
good shape.
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the vehicle
on a long downhill slope can cause
brake overheating, can reduce brake
performance, and could result in a
loss of braking. Shift the
transmission to a lower gear to let
the engine assist the brakes on a
steep downhill slope.
{Warning
Coasting downhill in N (Neutral) or
with the ignition off is dangerous.
This can cause overheating of the
brakes and loss of steering assist.
Always have the engine running
and the vehicle in gear.
.Drive at speeds that keep the
vehicle in its own lane. Do not
swing wide or cross the center line.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
218 DRIVING AND OPERATING
Starting and Operating
New Vehicle Break-In
Follow these recommended guidelines
during the first 2 400 km (1,500 mi) of
driving this vehicle. Parts have a
break-in period and performance will
be better in the long run.
For the first 2 400 km (1,500 mi):
.Avoid full throttle starts and abrupt
stops.
.Do not exceed 4000 engine rpm.
.Avoid driving at any one constant
speed, fast or slow.
.Avoid downshifting to brake or slow
the vehicle when the engine speed
will exceed 4000 rpm.
.Do not let the engine labor. Never
lug the engine in high gear at low
speeds.
.Do not participate in track events,
sport driving schools, or similar
activities during this break-in
period.
.Check engine oil with every
refueling and add if necessary. Oil
and fuel consumption may be
higher than normal during the first
2 400 km (1,500 mi).
.To break in new tires, drive at
moderate speeds and avoid hard
cornering for the first
300 km (200 mi). New tires do not
have maximum traction and may
tend to slip.
.New brake linings also need a
break-in period. Avoid making hard
stops during the first
300 km (200 mi). This is
recommended every time brake
linings are replaced.
Composite Materials
This vehicle may be equipped with
parts containing carbon fiber,
sheet-molding compound, or other
composite materials. Dealer-installed
accessories may also contain
composite materials.
{Warning
Exposed edges of parts containing
carbon fiber and other composite
materials can be sharp. Contact
with these parts could result in
injury. Use caution to avoid
contacting these parts, including
when washing the vehicle. If the
parts are damaged, replace the
parts promptly with replacements
from your dealer.
{Warning
Rocker extensions may break under
pressure, resulting in property
damage or injury. Do not stand on
the rocker extension or use it as
a step.
{Warning
Rear end spoilers may break under
pressure, resulting in property
damage or injury. Do not push the
vehicle by the spoiler or use the
spoiler as a handle.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
222 DRIVING AND OPERATING
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
Starts may occur because:
.The climate control settings require
the engine to be running to cool or
heat the vehicle interior.
.The vehicle battery needs to charge.
.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).
.Certain driver modes have been
selected. SeeDriver Mode Control
0 241.
.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 pressing the switch with the
h
symbol. Auto Stop is enabled each
time you start the vehicle.
When
his illuminated, the system is
enabled.
Engine Heater
Vehicles with the engine heater can
use this option 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 starting your vehicle. An
internal thermostat in the plug-end of
the cord may exist which will prevent
engine heater operation at
temperatures above −18 °C (0 °F).
The engine heater cord requires the
front license plate mounting bracket
to be installed. See your dealer for
more information.
To Use the Engine Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The cord is clipped
to the diagonal brace on the
passenger side of the engine
compartment.
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.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
226 DRIVING AND OPERATING
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).
6. 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.
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.
See Shifting Into Park (Mechanical
Shifter) 0223 or
Shifting Into Park (Electronic Shifter)
0 224 and
Engine Exhaust 0226.
If the vehicle is left parked and
running with the remote key outside
the vehicle, it will continue to run for
up to 15 minutes. If the vehicle is left parked and
running with the remote key inside
the vehicle, it will continue to run for
up to 30 minutes.
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). (Continued)