Page 317 of 438

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
316 VEHICLE CARE
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.
. A fluid leak in the brake hydraulic
system. Have the brake hydraulic
system fixed. With a leak, the
brakes will not work well.
Always clean the brake fluid reservoir
cap and the area around the cap
before removing it.
Do not top off the brake fluid. Adding
fluid does not correct a leak. If fluid is
added when the linings are worn,
there will be too much fluid when
new brake linings are installed. Add or
remove fluid, as necessary, only when
work is done on the brake hydraulic
system.{Warning
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You or
others could be burned, and the
vehicle could be damaged. Add
brake fluid only when work is done
on the brake hydraulic system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning Light
(3.0L Twin Turbo and 3.6L V6 Engines)
0 141 orBrake System Warning Light
(2.0L L4 Turbo and 4.2L Twin Turbo
V8 Engines) 0142.
Brake fluid absorbs water over time
which degrades the effectiveness of
the brake fluid. Replace brake fluid at
the specified intervals to prevent
increased stopping distance. See
Maintenance Schedule 0383. What to Add
Use only GM approved DOT 3 brake
fluid from a clean, sealed container.
See
Recommended Fluids and
Lubricants 0392.
{Warning
The wrong or contaminated brake
fluid could result in damage to the
brake system. This could result in
the loss of braking leading to a
possible injury. Always use the
proper GM approved brake fluid.
Caution
If brake fluid is spilled on the
vehicle's painted surfaces, the paint
finish can be damaged. Immediately
wash off any painted surface.
Battery - North America
The original equipment battery is
maintenance free. Do not remove the
cap and do not add fluid.
Page 319 of 438

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
318 VEHICLE CARE
Transfer Case
When to Check Lubricant
It is not necessary to regularly check
the transfer case fluid unless a leak is
suspected or an unusual noise is
heard. A fluid loss could indicate a
problem. Have it inspected and
repaired.
How to Check Lubricant
1. Fill Plug
2. Drain Plug
To get an accurate reading, the vehicle
should be on a level surface.If the level is below the bottom of the
fill plug hole on the transfer case,
some lubricant will need to be added.
Add enough lubricant to raise the
level to the bottom of the fill plug
hole. Use care not to overtighten the
fill plug.
What to Use
To determine what kind of lubricant
to use, see
Recommended Fluids and
Lubricants 0392.
Starter Switch Check
{Warning
When you are doing this inspection,
the vehicle could move suddenly.
If the vehicle moves, you or others
could be injured.
1. Before starting this check, be sure there is enough room
around the vehicle. 2. Firmly apply both the parking
brake and the regular brake. Do
not use the accelerator pedal,
and be ready to turn off the
engine immediately if it starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer for
service.
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.
Page 320 of 438

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
VEHICLE CARE 319
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 or cracking.
For the proper type and size, see
Maintenance Replacement Parts 0393. To replace the wiper blade assembly:
1. Pull the windshield wiper assembly away from the
windshield.
2. Lift up on the latch in the middleof the wiper blade where the
wiper arm attaches.
3. With the latch open, pull the wiper blade down toward the
windshield far enough to release
it from the J-hooked end of the
wiper arm.
4. Remove the wiper blade.
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.
5. Reverse Steps 1–3 for wiper blade replacement.
Windshield Replacement
Head-Up Display (HUD) System
The windshield is part of the HUD
system. If the windshield must be
replaced, get one that is designed for
HUD or the HUD image may look out
of focus.
Driver Assistance Systems
When a windshield replacement is
needed and the vehicle is equipped
with a front-looking camera sensor for
the Driver Assistance Systems, the
windshield must be installed
Page 326 of 438

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
VEHICLE CARE 325
FusesUsage
22 Transmission auxiliary oil pump
cooling
23 –
24 Cabin heater pump
26 Engine control module ignition
27 Steering column lock ignition
28 Rear heated seats ignition
29 Front heated seats ignition
30 –
31 Headlamp/Daytime running lamps/Right
headlamp
32 –
33 –
34 –
35 Engine control module ignition –2 Fuses
Usage
36 Engine control module ignition –1
37 Coolant pump/ Ignition coils –odd
38 Ignition coils –even/
Non walk 2
39 Non walk
40 Electric brake control module1/Instrument
cluster/central
gateway module
ignition
41 –
42 Fuel tank zone module/Ignition
43 Heated steering wheel module/
Reflective light aux
display/HVAC IGN/
Automatic occupant
sensing display
44 Aeroshutter
45 Washer Fuses
Usage
46 Front short range radar sensors
47 Left cornering LED
54 –
55 –
56 –
57 –
58 –
59 –
60 Antilock brake system pump/Electric
brake control
module–1
61 Front wiper
62 Headlamp leveling
63 –
64 –
66 Transfer case control module
67 –
68 –
Page 327 of 438
Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
326 VEHICLE CARE
FusesUsage
69 –
70 –
71 Antilock brake system valve
72 –
73 –
Relays Usage
14 Air conditioning control
15 Starter motor
16 Starter pinion
17 Run/Crank
19 –
20 High-beam headlamp
25 Cabin heater pump
48 –
49 –
50 Engine control module
51 Wiper speed Relays
Usage
52 Wiper control
53 Headlamp control
65 –
4.2L Engine
The 4.2L engine has an underhood
fuse block on each side of the engine
compartment.
Driver Side Fuse Block
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.
Page 328 of 438
Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
VEHICLE CARE 327
FusesUsage
F1 –
F2 –
F3 –
F4 –
F5 High-beam headlamps left/right Fuses
Usage
F6 –
F7 Front wiper
F8 –
F9 Instrument cluster/ Electric brake control
module 1/Central
gateway module
ignition Fuses
Usage
F10 –
F11 Transmission control/Transfer case
control module
ignition
F12 –
F13 Front heated seats ignition
F14 Exhaust valve solenoid
F15 Rear heated seats ignition
F16 Fuel tank zone module ignition
F17 –
F18 –
F19 –
F20 –
F21 Heated steering wheel module/
Reflective light aux
Page 329 of 438
Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
328 VEHICLE CARE
FusesUsage
display/HVAC IGN/
Automatic occupant
sensing display
F22 Electric steering column lock ignition
F23 Washer
F24 Left cornering LED
F25 –
F26 –
F27 –
F28 –
F29 Electric brake control module–1
Relays Usage
R1 –
R2 –
R3 –
R4 High-beam headlamp
R5 Wiper control
R6 Wiper speed Relays
Usage
R7 Run/Crank
R8 –
The 8-cylinder engine has an
underhood fuse block on each side of
the engine compartment.
Passenger Side Fuse Block
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.
Page 330 of 438
Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
VEHICLE CARE 329
FusesUsage
F1 Electric brake control module–2
F2 –
F3 Headlamp/Daytime running lamps
F4 Right cornering LED
F5 – Fuses
Usage
F6 Front short range radar sensors
F7 Horn
F8 Air conditioning clutch
F9 –
F10 – Fuses
Usage
F11 Automatic headlamp leveling
F12 Starter motor
F13 Starter pinion
F14 –
F15 –
F16 –
F17 Cabin heater pump
F18 Transmission auxiliary oil pump
cooling
F19 Engine control module ignition
F20 Non walk
F21 Ignition coils –even/
Non walk –2
F22 Engine control module ignition –1
F23 Transfer case control module
F24 –
F25 Ignition coils –odd