2021 CADILLAC CT4 ignition

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
334 VEHICLE CARE
FusesUsage
26 Engine control module
27 Injectors/Ignition 2
28 Charged air cooler
29 Transmission aux oil pump/Transmission
reverse lock out
30 Injectors/Ignition 1
31 Emissions 1
32 Emissions 2
33 Starter solenoid
34 –
35 –
36 Starter pinion
37 AC clutch
38 –
39 –
40 –
41 –
42 Water pump
43 – Fuses
Usage
44 –
Relays Usage
47 –
48 Front wiper speed
49 Front wiper control
51 –
52 Engine control module
53 Starter solenoid
54 Starter pinion
55 –
57 AC clutch
58 –Instrument Panel Fuse
Block
The instrument panel fuse block is in
the end of the driver side of the
instrument panel.
To access the fuses, remove the end
panel by gently prying with a plastic
tool near each clip, beginning at the
point shown.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
336 VEHICLE CARE
FusesUsage
13 –
14 –
15 –
16 –
17 –
18 Display/Infotainment/ USB/Multi-function
control module
19 Airbag/ Automatic occupant sensing /
Data link connection/
Wireless charging
module/ Virtual key
module
20 Power steering column module/
Electronic steering
column lock 2
21 Driver monitor system/Performance
data recorder
22 –
23 –
24 – Fuses
Usage
25 USB
26 –
27 –
28 –
29 –
30 –
31 Headlamp level
32 –
33 Body ignition/IP ignition
34 Exhaust valve
35 Transmission control module ignition/
Engine control
module ignition/Shift
ignition/Brake
ignition
36 Shift module
37 Body control module 1/Electronic
park brake switch
38 Center stack module Fuses
Usage
39 Steering wheel controls
40 Body control module 2
41 Body control module 3
42 Body control module 4
Circuit
Breakers Usage
CB1 Auxiliary power outlet 1
CB2 Auxiliary power outlet 2
Relays Usage
1 Run after park/ Accessory
2 Run crank
3 –
4 –
5 –

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 349
soon as possible, and inflate them to
the proper pressure. Driving on a
significantly under-inflated tire causes
the tire to overheat and can lead to
tire failure. Under-inflation also
reduces fuel efficiency and tire tread
life, and may affect the vehicle's
handling and stopping ability.
Please note that the TPMS is not a
substitute for proper tire maintenance,
and it is the driver's responsibility to
maintain correct tire pressure, even if
under-inflation has not reached the
level to trigger illumination of the
TPMS low tire pressure telltale.
Your vehicle has also been equipped
with a TPMS malfunction indicator to
indicate when the system is not
operating properly. The TPMS
malfunction indicator is combined
with the low tire pressure telltale.
When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated. This
sequence will continue upon
subsequent vehicle start-ups as long
as the malfunction exists.When the malfunction indicator is
illuminated, the system may not be
able to detect or signal low tire
pressure as intended. TPMS
malfunctions may occur for a variety
of reasons, including the installation
of replacement or alternate tires or
wheels on the vehicle that prevent the
TPMS from functioning properly.
Always check the TPMS malfunction
telltale after replacing one or more
tires or wheels on your vehicle to
ensure that the replacement or
alternate tires and wheels allow the
TPMS to continue to function
properly.
See
Tire Pressure Monitor Operation
0 349.
See Radio Frequency Statement 0409.
Tire Pressure Monitor
Operation
This vehicle may have a Tire Pressure
Monitor System (TPMS). The TPMS is
designed to warn the driver when a
low tire pressure condition exists. TPMS sensors are mounted onto each
tire and wheel assembly, excluding the
spare tire and wheel assembly. The
TPMS sensors monitor the air
pressure in the tires and transmit the
tire pressure readings to a receiver
located in the vehicle.
When a low tire pressure condition is
detected, the TPMS illuminates the
low tire pressure warning light located
on the instrument cluster. If the
warning light comes on, stop as soon
as possible and inflate the tires to the
recommended pressure shown on the
Tire and Loading Information label.
See
Vehicle Load Limits 0214.
A message to check the pressure in a
specific tire displays in the Driver
Information Center (DIC). The low tire
pressure warning light and the DIC
warning message come on at each
ignition cycle until the tires are
inflated to the correct inflation

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
350 VEHICLE CARE
pressure. Using the DIC, tire pressure
levels can be viewed. For additional
information and details about the DIC
operation and displays seeDriver
Information Center (DIC) (Base Level)
0 107 or
Driver Information Center (DIC)
(Uplevel) 0110.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as the vehicle is driven. This
could be an early indicator that the air
pressure is getting low and needs to
be inflated to the proper pressure.
A Tire and Loading Information label,
attached to your vehicle, shows the
size of the original equipment tires
and the correct inflation pressure for
the tires when they are cold. See
Vehicle Load Limits 0214, for an
example of the Tire and Loading
Information label and its location.
Also see Tire Pressure 0346.
The TPMS can warn about a low tire
pressure condition but it does not replace normal tire maintenance. See
Tire Inspection
0352, Tire Rotation
0 352 and
Tires 0339.
Caution
Tire sealant materials are not all
the same. A non-approved tire
sealant could damage the TPMS
sensors. TPMS sensor damage
caused by using an incorrect tire
sealant is not covered by the
vehicle warranty. Always use only
the GM approved tire sealant
available through your dealer or
included in the vehicle.
Factory-installed Tire Inflator Kits use
a GM-approved liquid tire sealant.
Using non-approved tire sealants
could damage the TPMS sensors. See
Tire Sealant and Compressor Kit 0360
for information regarding the inflator
kit materials and instructions.
TPMS Malfunction Light and
Message
The TPMS will not function properly if
one or more of the TPMS sensors are
missing or inoperable. When the
system detects a malfunction, the low
tire pressure warning light flashes for
about one minute and then stays on
for the remainder of the ignition cycle.
A DIC warning message also displays.
The malfunction light and DIC
warning message come on at each
ignition cycle until the problem is
corrected. Some of the conditions that
can cause these to come on are:
.One of the road tires has been
replaced with the spare tire. The
spare tire does not have a TPMS
sensor. The malfunction light and
DIC message should go off after the
road tire is replaced and the sensor
matching process is performed
successfully. See “TPMS Sensor
Matching Process” later in this
section.
.The TPMS sensor matching process
was not done or not completed
successfully after rotating the tires.
The malfunction light and the DIC

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
414 ONSTAR
.Obtain and customize the Wi-Fi
hotspot name or SSID and
password, if equipped.
Press
Qto connect to an Advisor to:
.Verify account information or
update contact information.
.Get driving directions.
.Receive a Diagnostic check of the
vehicle's key operating systems.
.Receive Roadside Service.
.Manage Wi-Fi Settings, if equipped.
Press
>to get a priority connection
to an OnStar Advisor available 24/7 to:
.Get help for an emergency.
.Be a Good Samaritan or respond to
an AMBER Alert.
.Get assistance in severe weather or
other crisis situations and find
evacuation routes.
OnStar Services
Emergency
Emergency Services require an active
safety and security plan. With
Automatic Crash Response, built-in
sensors can automatically alert a specially trained OnStar Advisor who
is immediately connected in to the
vehicle to help.
Press
>for a priority connection to
an OnStar Advisor who can contact
emergency service providers, direct
them to your exact location, and relay
important information.
With OnStar Crisis Assist, specially
trained Advisors are available
24 hours a day, 7 days a week, to
provide a central point of contact,
assistance, and information during a
crisis.
With Roadside Service, Advisors can
locate a nearby service provider to
help with a flat tire, a battery jump,
or an empty gas tank.
Security
If equipped, OnStar provides these
services:
.With Stolen Vehicle Assistance,
OnStar Advisors can use GPS to
pinpoint the vehicle and help
authorities quickly recover it.
.With Remote Ignition Block,
if equipped, OnStar can block the
engine from being restarted.
.With Stolen Vehicle Slowdown,
if equipped, OnStar can work with
law enforcement to gradually slow
the vehicle down.
Theft Alarm Notification
If equipped, if the doors are locked
and the vehicle alarm sounds, a
notification by text, e-mail, or phone
call will be sent. If the vehicle is
stolen, an OnStar Advisor can work
with authorities to recover the vehicle.
OnStar Additional
Information
In-Vehicle Audio Messages
Audio messages may play important
information at the following times:
.Prior to vehicle purchase. PressQ
to set up an account.
.After change in ownership and at
90 days.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
416 ONSTAR
TTY Users
OnStar has the ability to communicate
to deaf, hard-of-hearing,
or speech-impaired customers while in
the vehicle. The available
dealer-installed TTY system can
provide in-vehicle access to all OnStar
services, except Virtual Advisor and
OnStar Turn-by-Turn Navigation.
If equipped, TTY mode can be turned
on or off by touching Settings, then
Apps, and then Phone. When TTY
mode is on, phone calls can be made
or received with OnStar using the
infotainment display.
OnStar Personal Identification
Number (PIN)
A PIN is needed to access some
OnStar services. The PIN will need to
be changed the first time when
speaking with an Advisor. To change
the OnStar PIN, contact an OnStar
Advisor by pressing
Qor calling
1-888-4ONSTAR.
Warranty
OnStar equipment may be warranted
as part of the vehicle warranty.
Languages
The vehicle can be programmed to
respond in multiple languages. Press
Qand ask for an Advisor. Advisors
are available in English, Spanish, and
French. Available languages may vary
by country.
Potential Issues
OnStar cannot perform Remote Door
Unlock or Stolen Vehicle Assistance
after the vehicle has been off
continuously for 10 days without an
ignition cycle. If the vehicle has not
been started for 10 days, OnStar can
contact Roadside Service or a
locksmith to help gain access to the
vehicle.
Global Positioning System (GPS)
.Obstruction of the GPS can occur in
a large city with tall buildings; in
parking garages; around airports; in
tunnels and underpasses; or in an
area with very dense trees. If GPS
signals are not available, the OnStar
system should still operate to call
OnStar. However, OnStar could have
difficulty identifying the exact
location.
.In emergency situations, OnStar can
use the last stored GPS location to
send to emergency responders.
A temporary loss of GPS can cause
loss of the ability to send a
Turn-by-Turn Navigation route. The
Advisor may give a verbal route or
may ask for a call back after the
vehicle is driven into an open area.
Cellular and GPS Antennas
Cellular reception is required for
OnStar to send remote signals to the
vehicle. Do not place items over or
near the antenna to prevent blocking
cellular and GPS signal reception.
Unable to Connect to OnStar
Message
If there is limited cellular coverage or
the cellular network has reached
maximum capacity, this message may
come on. Press
Qto try the call again
or try again after driving a few miles
into another cellular area.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
426 INDEX
Headlamps (cont'd)High/Low Beam Changer . . . . . . . . . 128
Lamps On Reminder . . . . . . . . . . . . . . 106
Heated Steering Wheel . . . . . . . . . . . . . . . . . . . . . 82
Heated and Ventilated Front Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . 25
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
High-Beam On Light . . . . . . . . . . . . . . . . 105
High-Speed Operation . . . . . . . . . . . . . . 347
Hill and Mountain Roads . . . . . . . . . . 212
Hill Start Assist (HSA) . . . . . . . . . . . . . 238
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
How to Wear Seat Belts Properly . . . 42
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
I
If the System Needs Service . . . . . . . 163
Ignition Positions . . . . . . . . . . . . . . . . . . . 219
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Indicator Pedestrian Ahead . . . . . . . . . . . . . . . . . 102
Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . 102 Infants and Young Children,
Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Information Publication Ordering . . . . . . . . . . . . . 408
Infotainment System . . . . . . . . . . . . . . . 412
Instrument Cluster . . . . . . . . . . . . . . 88, 90
Instrument Panel Overview . . . . . . . . . . . 4
Interior Rearview Mirrors . . . . . . . . . . . 26
Introduction . . . . . . . . . . . . . . . . . . . . . . 1, 134
J
Jump Starting - North America . . . . 366
K
Keyless Entry Remote (RKE) System . . . . . . . . . . . . . . . 7
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
L
Labeling, Tire Sidewall . . . . . . . . . . . . . 342
Lamps
Cornering . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Courtesy . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Daytime Running (DRL) . . . . . . . . . . 128
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Exterior Controls . . . . . . . . . . . . . . . . . . 126
Exterior Lamps Off Reminder . . . . 128
Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Lamps (cont'd)
Front Turn Signal . . . . . . . . . . . . . . . . . 330
Malfunction Indicator (Check
Engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
On Reminder . . . . . . . . . . . . . . . . . . . . . . 106
Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Lane Change Alert (LCA) . . . . . . . . . . . 289
Lane Keep Assist (LKA) . . . . . . . . . . . . 291
Lane Keep Assist Light . . . . . . . . . . . . . 101
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . 44
LATCH System Replacing Parts after a Crash . . . . . 72
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . . . . 65
LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . 330
Light Performance Shifting . . . . . . . . . . . . . 101
Lighting Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Illumination Control . . . . . . . . . . . . . . 130
LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Lights Airbag Readiness . . . . . . . . . . . . . . . . . . 96
Antilock Brake System (ABS)Warning . . . . . . . . . . . . . . . . . . . . . . . . . 100
Automatic Vehicle Hold . . . . . . . . . . 101
Brake System Warning . . . . . . . . . . . . 99