2021 CADILLAC CT4 check engine

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 327
Warning (Continued)
careful. SeeJump Starting - North
America 0366 for tips on working
around a battery without
getting hurt.
Infrequent Usage: Remove the black,
negative (−) cable from the battery to
keep the battery from running down.
Extended Storage: Remove the black,
negative (−) cable from the battery or
use a battery trickle charger.
All-Wheel Drive
If the vehicle is equipped with
All-Wheel-Drive (AWD), this is an
additional system that needs
lubrication.
Transfer Case
Under normal driving conditions,
transfer case fluid does not require
maintenance unless there is a fluid
leak or unusual noise. If required,
have the transfer case serviced by
your dealer.
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check, the
vehicle could begin to move. You or
others could be injured and
property could be damaged. Make
sure there is room in front of the
vehicle in case it begins to roll. Be
ready to apply the regular brake at
once should the vehicle begin
to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping your
foot on the regular brake, set the
parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
.To check the P (Park) mechanism's
holding ability: With the engine
running, shift to P (Park). Then
release the parking brake followed
by the regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear and cracking. See
Maintenance Schedule 0380.
Replacement blades come in different
types and are removed in different
ways. For proper type and length, see
Maintenance Replacement Parts 0392.
Caution
Allowing the wiper arm to touch
the windshield when no wiper blade
is installed could damage the
windshield. Any damage that occurs
would not be covered by the vehicle
warranty. Do not allow the wiper
arm to touch the windshield.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
332 VEHICLE CARE
{Warning
Installation or use of fuses that do
not meet GM’s original fuse
specifications is dangerous. The
fuses could fail, and result in a fire.
You or others could be injured or
killed, and the vehicle could be
damaged.
See Accessories and Modifications
0 306 and
General Information 0305.
To check a fuse, look at the
silver-colored band inside the fuse.
If the band is broken or melted,
replace the fuse. Be sure to replace a
bad fuse with a new one of the
identical size and rating.
Fuses of the same amperage can be
temporarily borrowed from another
fuse location, if a fuse goes out.
Replace the fuse as soon as possible.
Engine Compartment Fuse
Block
The engine compartment fuse block is
on the driver side of the engine
compartment.
Lift the fuse block cover to access the
fuses. The vehicle may not be equipped with
all of the fuses and relays shown.
Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the covers
on any electrical component.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 367
2.0L L4 Engine Shown, 2.7L L4 EngineSimilar
1. Discharged Battery Remote
Positive Terminal
2. Discharged Battery Negative Grounding Terminal
3. Good Battery Negative Terminal
4. Good Battery Positive Terminal
The jump start positive terminal (4)
and negative post (3) are on the
battery of the vehicle providing the
jump start. The jump start remote positive
terminal (1) and the remote negative
grounding terminal (2) for the
discharged battery are on the
passenger side of the vehicle.
The positive jump start connection for
the discharged battery is under a
cover. Lift the cover to expose the
terminal.
1. Check the other vehicle. It must have a 12-volt battery with a
negative ground system.
Caution
If the other vehicle does not have a
12-volt system with a negative
ground, both vehicles can be
damaged. Only use a vehicle that
has a 12-volt system with a
negative ground for jump starting.
2. Position the two vehicles so that they are not touching.
3. Set the parking brake firmly and put the shift lever in P (Park) with
an automatic transmission,
or Neutral with a manual
transmission.
Caution
If any accessories are left on or
plugged in during the jump starting
procedure, they could be damaged.
The repairs would not be covered
by the vehicle warranty. Whenever
possible, turn off or unplug all
accessories on either vehicle when
jump starting.
4. Turn the ignition off. Turn off all lights and accessories in both
vehicles, except the hazard warning
flashers if needed.
{Warning
An electric fan can start up even
when the engine is not running and
can injure you. Keep hands,
clothing, and tools away from any
underhood electric fan.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 373
Shutter System
The vehicle may have a shutter
system designed to help improve fuel
economy. Keep the shutter system
clear of debris, snow and ice. If the
check engine light is activated, please
check to see if the shutter system is
clear of debris, snow or ice.
Windshield and Wiper Blades
Clean the outside of the windshield
with glass cleaner.
Clean rubber blades using a lint-free
cloth or paper towel soaked with
windshield washer fluid or a mild
detergent. Wash the windshield
thoroughly when cleaning the blades.Bugs, road grime, sap, and a buildup
of vehicle wash/wax treatments may
cause wiper streaking.
Replace the wiper blades if they are
worn or damaged. Damage can be
caused by extreme dusty conditions,
sand, salt, heat, sun, snow, and ice.
Weatherstrips
Apply weatherstrip lubricant on
weatherstrips to make them last
longer, seal better, and not stick or
squeak. Lubricate weatherstrips at
least once a year. Hot, dry climates
may require more frequent
application. Black marks from rubber
material on painted surfaces can be
removed by rubbing with a clean
cloth. See
Recommended Fluids and
Lubricants 0391.
Tires
Use a stiff brush with tire cleaner to
clean the tires.
Caution
Using petroleum-based tire dressing
products on the vehicle may
damage the paint finish and/or
tires. When applying a tire dressing,
always wipe off any overspray from
all painted surfaces on the vehicle.
Wheels and Wheel Trim
Use a soft, clean cloth with mild soap
and water to clean the wheels. After
rinsing thoroughly with clean water,
dry with a soft, clean towel. A wax
may then be applied.
Caution
Chrome wheels and chrome wheel
trim may be damaged if the vehicle
is not washed after driving on roads
that have been sprayed with
magnesium chloride or calcium
chloride. These are used on roads
for conditions such as dust and ice.
Always wash the chrome with soap
and water after exposure.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
380 SERVICE AND MAINTENANCE
keep the vehicle in good working
condition, improves fuel economy, and
reduces vehicle emissions.
Because of the way people use
vehicles, maintenance needs vary.
There may need to be more frequent
checks and services. The Additional
Required Services - Normal are for
vehicles that:
.Carry passengers and cargo within
recommended limits on the Tire
and Loading Information label. See
Vehicle Load Limits0214.
.Are driven on reasonable road
surfaces within legal driving limits.
.Use the recommended fuel. See
Recommended Fuel (LSY 2.0L L4
Turbo Engine) 0293 or
Recommended Fuel (L3B 2.7L L4
Turbo Engine) 0294.
Refer to the information in the
Maintenance Schedule Additional
Required Services - Normal chart. The Additional Required Services -
Severe are for vehicles that are:
.Mainly driven in heavy city traffic
in hot weather.
.Mainly driven in hilly or
mountainous terrain.
.Used for high speed or competitive
driving.
.Used for taxi, police, or delivery
service.
Refer to the information in the
Maintenance Schedule Additional
Required Services - Severe chart.
{Warning
Performing maintenance work can
be dangerous and can cause serious
injury. Perform maintenance work
only if the required information,
proper tools, and equipment are
available. If they are not, see your
dealer to have a trained technician
do the work. See Doing Your Own
Service Work 0306.
Maintenance Schedule
Owner Checks and Services
Check the engine oil level. See Engine
Oil 0312.
Once a Month
.Check the tire inflation pressures.
See Tire Pressure 0346.
.Inspect the tires for wear. See Tire
Inspection 0352.
.Check the windshield washer fluid
level. See Washer Fluid 0323.
Engine Oil Change
When the CHANGE ENGINE OIL
SOON message displays, have the
engine oil and filter changed within
the next 1 000 km (600 mi ). If driven
under the best conditions, the engine
oil life system may not indicate the
need for vehicle service for up to a
year. The engine oil and filter must be
changed at least once a year and the

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
SERVICE AND MAINTENANCE 381
oil life system must be reset. Your
trained dealer technician can perform
this work. If the engine oil life system
is reset accidentally, service the
vehicle within 5 000 km (3,000 mi)
since the last service. Reset the oil life
system when the oil is changed. See
Engine Oil Life System0314.
Air Conditioning Desiccant
(Replace Every Seven Years)
The air conditioning system requires
maintenance every seven years. This
service requires replacement of the
desiccant to help the longevity and
efficient operation of the air
conditioning system. This service can
be complex. See your dealer.
Tire Rotation and Required
Services Every 12 000 km
(7,500 mi)
Rotate the tires, if recommended for
the vehicle, and perform the following
services. See Tire Rotation0352.
.Check engine oil level and oil
life percentage. If needed, change
engine oil and filter, and reset oil
life system. See Engine Oil0312 and
Engine Oil Life System 0314.
.If equipped, check the air filter
life percentage. If necessary, replace
the engine air filter and reset the
engine air filter life system. See
Engine Air Filter Life System 0315.
If the vehicle is not equipped with
the engine air filter life system,
inspect the engine air cleaner filter.
See Engine Air Cleaner/Filter 0316.
.Check engine coolant level. See
Cooling System 0317.
.Check windshield washer fluid level.
See Washer Fluid 0323.
.Check tire inflation pressures. See
Tire Pressure 0346.
.Inspect tire wear. See Tire Inspection
0 352.
.Visually check for fluid leaks.
.Inspect brake system. See Exterior
Care 0370.
.Visually inspect steering,
suspension, and chassis
components for damage, including
cracks or tears in the rubber boots,
loose or missing parts, or signs of
wear at least once a year. See
Exterior Care 0370.
.Inspect power steering for proper
attachment, connections, binding,
leaks, cracks, chafing, etc.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
SERVICE AND MAINTENANCE 383
Maintenance Schedule
Additional Required Services -
Normal12 000 km/7,500 mi
24 000 km/15,000 mi
36 000 km/22,500 mi
48 000 km/30,000 mi
60 000 km/37,500 mi
72 000 km/45,000 mi
84 000 km/52,500 mi
96 000 km/60,000 mi
108 000 km/67,500 mi
120 000 km/75,000 mi
132 000 km/82,500 mi
144 000 km/90,000 mi
156 000 km/97,500 mi
168 000 km/105,000 mi
180 000 km/112,500 mi
192 000 km/120,000 mi
204 000 km/127,500 mi
216 000 km/135,000 mi
228 000 km/142,500 mi
240 000 k m/150,000 mi
Rotate tires, if recommended for the vehicle, and
perform Required Services. (1) Check engine oil level
and oil life percentage. Change engine oil and filter,
if needed.
If equipped, check engine air filter life percentage
and status. Change engine air filter, if needed.
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
Replace passenger compartment air filter. (2)@ @@@@@
If the vehicle is not equipped with the engine air
filter life system, replace engine air cleaner filter. (3)@ @@
Inspect evaporative control system. (4)@@@
Replace spark plugs. Inspect spark plug wires and/or
boots.@ @
Change transfer case fluid, if equipped with
AWD. (5)@
Change rear axle fluid, if equipped with limited slip
differential. (5)@@@

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
SERVICE AND MAINTENANCE 385
Footnotes—Maintenance Schedule
Additional Required Services -
Normal
(1) Vehicles with different size front
and rear tires do not have tire
rotation. See Tire Rotation0352.
(2) Or every two years, whichever
comes first. More frequent passenger
compartment air filter replacement
may be needed if driving in areas with
heavy traffic, poor air quality, high
dust levels, or environmental
allergens. Passenger compartment air
filter replacement may also be needed
if there is reduced airf low, window
fogging, or odors. Your GM dealer can
help determine when to replace the
filter.
(3) Or every four years, whichever
comes first. If driving in dusty
conditions, inspect the filter at each
oil change or more often as needed.
See Engine Air Cleaner/Filter 0316.
(4) Visually check all fuel and vapor
lines and hoses for proper attachment,
connection, routing, and condition. (5)
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.
(6) Or every five years, whichever
comes first. See Cooling System0317.
(7) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage; replace,
if needed.
(8) Replace brake fluid every five
years. See Brake Fluid 0325.
(9) Or every 12 months, whichever
comes first. See Wiper Blade
Replacement 0327.
(10) Or every 10 years, whichever
comes first. See Gas Strut(s)0328.
(11) Replace air conditioning
desiccant every seven years.