2018 CADILLAC CT6 check engine light

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
DRIVING AND OPERATING 277
Charging StatusIndicator Sound Action/Reason
Short Flashing Green
(From one to four
flashes depending on
charge level) One audible beep Charging has begun.
Long Flashing Green Two audible beeps Charging is delayed by Programmable Charging or, if the vehicle is equipped
accordingly, by a total utility interruption via
OnStar. Charging will begin later. SeeUtility
Interruption of Charging (PLUG-IN Only) 0284.
Solid Green None Charging is complete.
Yellow (Upon Plug-in) None Charge cord is OK and the vehicle is not yet charging.
Yellow (For Extended
Time Period after
Plug-in) None Charge cord is OK, but the vehicle is not
charging. This may be due to a total utility
interruption via Onstar and charging will
begin later. The condition may also occur if
the vehicle has detected a fault with the high
voltage charging system.
SeeUtility Interruption of Charging (PLUG-IN
Only) 0284 orMalfunction Indicator Lamp
(Check Engine Light) 0143.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
278 DRIVING AND OPERATING
Charging StatusIndicator Sound Action/Reason
Short Flashing Green
(From one to four
flashes depending on
charge level) Two audible beeps Vehicle is charging but will delay at least once
before the charge is complete.
Short Flashing Green
(From one to four
flashes depending on
charge level) or Long
Flashing Green Four audible beeps Insufficient time to fully charge by departure
time due to rate preference.
None (Upon Plug-in) None Charge cord connection should be checked.
None (After Green or
Yellow CSI Indication
Observed) None Charge cord connection should be checked.
If connection is good, this may be due to a
total utility interruption via OnStar and
charging will begin later. The condition may
also occur if the vehicle has detected a fault
with the high voltage charging system.
SeeUtility Interruption of Charging (PLUG-IN
Only) 0284 orMalfunction Indicator Lamp
(Check Engine Light) 0143.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
DRIVING AND OPERATING 287
by the vehicle warranty. If heavy
knocking is heard when using gasoline
rated at 93 octane, the engine needs
service.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so may
damage the vehicle and void its
warranty:. For vehicles which are not
FlexFuel, fuel labeled greater
than 15% ethanol by volume,
such as mid-level ethanol
blends (16 –50% ethanol),
E85, or FlexFuel.
. Fuel with any amount of
methanol, methylal, and
aniline. These fuels can
corrode metal fuel system
parts or damage plastic and
rubber parts.
. Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(Continued)
Caution (Continued)
(MMT), which can damage
the emissions control system
and spark plugs.
. Fuel with a posted octane
rating of less than the
recommended fuel. Using this
fuel will lower fuel economy
and performance, and may
decrease the life of the
emissions catalyst.
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that meet
California specifications. See the
underhood emission control label.
If this fuel is not available in states
adopting California Emissions
Standards, the vehicle will operate
satisfactorily on fuels meeting federal
specifications, but emission control
system performance may be affected.
The malfunction indicator lamp could
turn on and the vehicle may not pass a smog-check test. See
Malfunction
Indicator Lamp (Check Engine Light)
0 143. If this occurs, return to your
authorized dealer for diagnosis. If it is
determined that the condition is
caused by the type of fuel used,
repairs may not be covered by the
vehicle warranty.
Fuels in Foreign Countries
The U.S., Canada, and Mexico post
fuel octane ratings in anti-knock index
(AKI). For fuel not to use in a foreign
country, see “Prohibited Fuels” inFuel
0 286.
Fuel Additives
To keep fuel systems clean, TOP TIER
detergent gasoline is recommended.
See Fuel 0286.
If TOP TIER detergent gasoline is not
available, one bottle of GM Fuel
System Treatment Cleaner added to
the fuel tank at every engine oil
change, can help. GM Fuel System
Treatment Cleaner is the only gasoline
additive recommended by General
Motors. It is available at your dealer.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
DRIVING AND OPERATING 295
Because the vehicle has antilock
brakes, do not tap into the vehicle's
brake system. If this is done, both
brake systems will not work well or
at all.Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. SeeMalfunction Indicator
Lamp (Check Engine Light) 0143.
A device connected to the DLC —
such as an aftermarket fleet or
driver-behavior tracking device —
may interfere with vehicle systems.
This could affect vehicle operation
and cause a crash. Such devices
may also access information stored
in the vehicle’s systems.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and would
not be covered by the vehicle
warranty. Always check with your
dealer before adding electrical
equipment.
Add-on equipment can drain the
vehicle's 12-volt battery, even if the
vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see Servicing
the Airbag-Equipped Vehicle 095 and
Adding Equipment to the
Airbag-Equipped Vehicle 095.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
296 VEHICLE CARE
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 297
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 297
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 297
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 298
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 298
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 300
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 307
Engine Oil Life System . . . . . . . . . . . 309
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Engine Air Cleaner/Filter . . . . . . . . . 311
Cooling System (Gasoline Only) . . . . . . . . . . . . . . . . . 312
Cooling System (PLUG-IN Only) . . . . . . . . . . . . . . . . . 316
Engine Overheating . . . . . . . . . . . . . . 321
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 322
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 323 Battery - North America . . . . . . . . . 324
All-Wheel Drive . . . . . . . . . . . . . . . . . . 326
Starter Switch Check . . . . . . . . . . . . . 326
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . 327
Wiper Blade Replacement . . . . . . . 327
Windshield Replacement . . . . . . . . 328
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 328
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . . . . . 329
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 330
LED Lighting . . . . . . . . . . . . . . . . . . . . . 330
License Plate Lamp . . . . . . . . . . . . . . 330
Replacement Bulbs . . . . . . . . . . . . . . . 330
Electrical System
Electrical System Overload . . . . . . 331
Fuses and Circuit Breakers . . . . . . 331
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Instrument Panel Fuse Block . . . . 335
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340 All-Season Tires . . . . . . . . . . . . . . . . . . 341
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 341
Low-Profile Tires . . . . . . . . . . . . . . . . . 342
Summer Tires . . . . . . . . . . . . . . . . . . . . 342
Tire Sidewall Labeling . . . . . . . . . . . 342
Tire Designations . . . . . . . . . . . . . . . . . 344
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . . . . . 345
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 347
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 349
Tire Pressure Monitor System . . . 349
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 350
Tire Inspection . . . . . . . . . . . . . . . . . . . 353
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 353
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355
Buying New Tires . . . . . . . . . . . . . . . . 355
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Uniform Tire Quality Grading . . . 357
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 359
Wheel Replacement . . . . . . . . . . . . . . 359
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 360
If a Tire Goes Flat . . . . . . . . . . . . . . . . 360
Tire Sealant and Compressor Kit . . . . . . . . . . . . . . . . . 362
Storing the Tire Sealant and Compressor Kit . . . . . . . . . . . . . . . . . 368

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 321
Engine Overheating
The vehicle has several indicators to
warn of the engine overheating.
There is an engine coolant
temperature gauge and an engine
coolant temperature warning light on
the instrument cluster.
SeeEngine Coolant Temperature Gauge
0 139 and Engine Coolant Temperature
Warning Light 0149. The vehicle may
also display a message on the Driver
Information Center (DIC).
If the decision is made not to lift the
hood when this warning appears, get
service help right away. See Roadside
Service 0411.
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.Caution
Do not run the engine if there is a
leak in the engine cooling system.
This can cause a loss of all coolant
and can damage the system and
vehicle. Have any leaks fixed
right away.
If Steam Is Coming from the
Engine Compartment
{Warning
Steam and scalding liquids from a
hot cooling system are under
pressure. Turning the pressure cap,
even a little, can cause them to
come out at high speed and you
could be burned. Never turn the cap
when the cooling system, including
the pressure cap, is hot. Wait for
the cooling system and pressure
cap to cool.
If No Steam Is Coming from the
Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen or
heard, the problem may not be too
serious. Sometimes the engine can get
a little too hot when the vehicle:
. Climbs a long hill on a hot day
. Stops after high-speed driving
. Idles for long periods in traffic
If the overheat warning is displayed
with no sign of steam: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest
fan speed. Open the windows as
necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or
N (Neutral), and let the
engine idle.
If the engine coolant temperature
gauge is no longer in the overheated
area or the engine coolant
temperature warning light no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 323
{Warning
The brake wear warning sound
means that soon the brakes will not
work well. That could lead to a
crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
Caution
Continuing to drive with worn-out
brake pads could result in costly
brake repair.
Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the proper sequence to torque
specifications. See
Capacities and
Specifications 0404.
Brake pads should be replaced as
complete sets.
Brake Pedal Travel
See your dealer if the brake pedal does
not return to normal height, or if
there is a rapid increase in pedal
travel. This could be a sign that brake
service may be required.
Replacing Brake System Parts
Always replace brake system parts
with new, approved replacement parts.
If this is not done, the brakes may not
work properly. The braking
performance expected can change in
many other ways if the wrong
replacement brake parts are installed
or if parts are improperly installed.
Brake Fluid
The brake master cylinder reservoir is
filled with GM approved DOT 3 (for
gasoline only vehicles) or DOT 4 (for
PLUG-IN vehicles) brake fluid as
indicated on the reservoir cap. See
Engine Compartment Overview 0300
for the location of the reservoir.
Checking Brake Fluid
With the vehicle in P (Park) on a level
surface, the brake fluid level should be
between the minimum and maximum
marks on the brake fluid reservoir.
There are only two reasons why the
brake fluid level in the reservoir may
go down:
. Normal brake lining wear. When
new linings are installed, the fluid
level goes back up.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 375
The jump start negative terminal (3)
and positive terminal (4) are on the
battery of the vehicle providing the
jump start.
The positive jump start connection for
the discharged battery is under a red
cover. Remove 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). See
Shifting Into Park 0224.
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.
{Warning
Using a match near a battery can
cause battery gas to explode. People
have been hurt doing this, and
some have been blinded. Use a
flashlight if you need more light.
Battery fluid contains acid that can
burn you. Do not get it on you.
If you accidentally get it in your
eyes or on your skin, flush the place
with water and get medical help
immediately.
{Warning
Fans or other moving engine parts
can injure you badly. Keep your
hands away from moving parts
once the engine is running.
5. Connect one end of the red positive (+) cable to the remote
positive (+) terminal on the
discharged battery.