
Black plate (86,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
9-86 Driving and Operating
Use the following to adjust Trailer
Gain for each towing condition:
1. Drive the vehicle with the trailerattached on a level road surface
representative of the towing
condition and free of traffic at
about 32 to 40 km/h (20 to
25 mph) and fully apply the
Manual Trailer Brake apply lever.
Adjusting Trailer Gain at speeds
lower than 32 to 40 km/h (20 to
25 mph) may result in an
incorrect gain setting.
2. Adjust the Trailer Gain, using the Trailer Gain adjustment buttons,
to just below the point of trailer
wheel lock-up, indicated by
trailer wheel squeal or tire
smoke when a trailer wheel
locks.
Trailer wheel lock-up may not
occur if towing a heavily loaded
trailer. In this case, adjust the
Trailer Gain to the highest
allowable setting for the towing
condition. 3. Readjust Trailer Gain any time
vehicle loading, trailer loading,
or road surface conditions
change or if trailer wheel lock-up
is noticed at any time while
towing.
Other ITBC-Related DIC Messages
In addition to displaying TRAILER
GAIN and OUTPUT through the
DIC, trailer connection and ITBC
system status are displayed on
the DIC.
TRAILER CONNECTED: This
message will briefly display when a
trailer with electric brakes is first
connected to the vehicle. This
message will automatically turn off
in about 10 seconds. This message
can be acknowledged before it
automatically turns off. CHECK TRAILER WIRING: This
message will display if:
.The ITBC system first
determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected from the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically turn
off in about 30 seconds. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
.There is an electrical fault in the
wiring to the trailer brakes. This
message will continue as long
as there is an electrical fault in

Black plate (87,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
Driving and Operating 9-87
the trailer wiring. This message
will also turn off if it is
acknowledged.
To determine if the electrical fault is
on the vehicle side or trailer side of
the trailer wiring harness
connection:
1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition off.
3. Wait 10 seconds, then turn the ignition back to RUN.
4. If the CHECK TRAILER WIRING message reappears, the
electrical fault is on the
vehicle side.
If the CHECK TRAILER WIRING
message only reappears when
connecting the trailer wiring
harness to the vehicle, the
electrical fault is on the
trailer side.
SERVICE TRAILER BRAKE
SYSTEM: This message will display
when there is a problem with the
ITBC system. If this message continues over multiple ignition
cycles, there is a problem with the
ITBC system. Have the vehicle
serviced.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message displays
while driving, the ITBC system may
not be fully functional or may not
function at all. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service.
A GM dealer may be able to
diagnose and repair problems with
the trailer. However, any diagnosis
and repair of the trailer is not
covered under the vehicle warranty.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.Trailer Sway
Control (TSC)
Vehicles with StabiliTrak have a
TSC feature. Trailer sway is
unintended side-to-side motion of a
trailer while being towed. If the
vehicle is towing a trailer and the
TSC detects that sway is increasing,
the vehicle brakes are selectively
applied at each wheel, to help
reduce excessive trailer sway. If the
vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, and the trailer has
the electric actuated brake system,
StabiliTrak may also apply the trailer
brakes.
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on the
instrument cluster. Vehicle speed
must be reduced. If trailer sway
continues, StabiliTrak can reduce
engine torque to help slow the
vehicle. See
Traction Control/
Electronic Stability Control on
page 9-44.

Black plate (88,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
9-88 Driving and Operating
{Warning
Even if the vehicle is equipped
with TSC, trailer sway could result
in loss of control and the vehicle
could crash. If excessive trailer
sway is detected, slow down to a
safe speed. Check the trailer and
vehicle to help correct possible
causes. These could include an
improperly or overloaded trailer,
unrestrained cargo, improper
trailer hitch configuration,
excessive vehicle-trailer speed,
or improperly inflated or incorrect
vehicle or trailer tires. SeeTowing
Equipment on page 9-81 for
trailer ratings and hitch setup
recommendations.
Adding non-dealer accessories can
affect the vehicle performance. See
Accessories and Modifications on
page 10-3.
Conversions and
Add-Ons
Add-On Electrical
Equipment
{Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and
would not be covered by the
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 on page 3-41 andAdding
Equipment to the Airbag-Equipped
Vehicle on page 3-42.

Black plate (20,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
10-20 Vehicle Care
If Steam is Coming from the
Engine Compartment
{Warning
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Just turn it
off and get everyone away from
the vehicle until it cools down.
Wait until there is no sign of
steam or coolant before you open
the hood.
If you keep driving when the
engine is overheated, the liquids
in it can catch fire. You or others
could be badly burned. Stop the
engine if it overheats, and get out
of the vehicle until the engine
is cool.
If No Steam is Coming from
the Engine Compartment
The ENGINE OVERHEATED STOP
ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message, along with a low coolant
condition, can indicate a serious
problem.
If there is an engine overheat
warning, but no steam is 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.
.Tows a trailer; seeTrailer Towing
on page 9-76.
If the ENGINE OVERHEATED
STOP ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message appears with no sign of
steam, try this for a minute or so:
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 temperature overheat gauge is
no longer in the overheat zone or an
overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe
vehicle distance from the vehicle in
front. If the warning does not come
back on, continue to drive normally
and have the cooling system
checked for proper fill and function.
If the warning continues, pull over,
stop, and park the vehicle
right away.
If there is still no sign of steam and
the vehicle is equipped with an
engine driven cooling fan, push
down the accelerator until the
engine speed is about twice as fast

Black plate (21,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
Vehicle Care 10-21
as normal idle speed for at least
five minutes while the vehicle is
parked. If the warning is still there,
turn off the engine and get everyone
out of the vehicle until it cools down.
If there is no sign of steam, idle the
engine for five minutes while
parked. If the warning is still
displayed, turn off the engine until it
cools down.
Engine Fan
If the vehicle has electric cooling
fans, the fans may be heard
spinning at low speed during most
everyday driving. The fans may turn
off if no cooling is required. Under
heavy vehicle loading, trailer towing,
high outside temperatures,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the cooling
system is functioning properly. Thefans will change to low speed when
additional cooling is no longer
required.
The electric engine cooling fans
may run after the engine has been
turned. off. This is normal and no
service is required.
Washer Fluid
What to Use
When windshield washer fluid needs
to be added, be sure to read the
manufacturer's instructions before
use. Use a fluid that has sufficient
protection against freezing in an
area where the temperature may fall
below freezing.
Adding Washer Fluid
The vehicle has a low washer fluid
message on the DIC that comes on
when the washer fluid is low. The
message is displayed for
15 seconds at the start of each
ignition cycle. When the WASHER
FLUID LOW ADD FLUID messagedisplays, washer fluid will need to
be added to the windshield washer
fluid reservoir.
Open the cap with the washer
symbol on it. Add washer fluid until
the tank is full. See
Engine
Compartment Overview on
page 10-6 for reservoir location.
{Caution
.Do not use engine coolant
(antifreeze) in the windshield
washer. It can damage the
windshield washer system
and paint.
.Do not mix water with
ready-to-use washer fluid.
Water can cause the solution
(Continued)

Black plate (38,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
10-38 Vehicle Care
ItemUsage
1 Electric Running Boards
2 Antilock Brake System Pump
3 Interior BEC LT1
4 MBS Passenger
5 Suspension Leveling
Compressor
6 4WD Transfer Case Electronic
Control
10 Electric Parking Brake
13 Interior BEC LT2
14 Rear BEC 1
17 MBS Driver
21 ALC Exhaust Solenoid
23 Integrated Chassis Control Module Item
Usage
24 Real Time Dampening
25 Fuel Pump Power Module
26 Spare/Battery Regulated Voltage
Control
28 Upfitter 2
29 Upfitter 2 Relay
30 Wiper
31 TIM
34 Back-up Lamps
35 Antilock Brake System Valve
36 Trailer Brakes
37 Upfitter 3 Relay
39 Trailer Stop/Turn Right
40 Trailer Stop/ Turn Left Item
Usage
41 Trailer Park Lamps
42 Right Parking Lamps
43 Left Parking Lamps
44 Upfitter 3
45 Automatic Level Control Run/Crank
47 Upfitter 4
48 Upfitter 4 Relay
49 Reverse Lamps
51 Parking Lamp Relay
59 Euro Trailer
60 Air Conditioning Control
63 Upfitter 1
67 Trailer Battery
69 RC Upfitter 3 and 4
70 VBAT Upfitter 3 and 4

Black plate (39,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
Vehicle Care 10-39
ItemUsage
72 Upfitter 1 Relay
74 Engine Control Module Ignition
75 Miscellaneous Ignition Spare
76 Transmission Ignition
77 RC Upfitter 1 and 2
78 VBAT Upfitter 1 and 2
83 Euro Trailer RC
84 Run/Crank Relay
87 Engine
88 Injector A –Odd
89 Injector B –Even
90 Oxygen Sensor B Item
Usage
91 Throttle Control
92 Engine Control Module Relay
93 Horn
94 Fog Lamps
95 High-Beam Headlamps
100 Oxygen Sensor A
101 Engine Control Module
102 Engine Control Module/
Transmission
Control Module
103 Auxiliary Interior Heater Item
Usage
104 Starter
107 Aero Shutter
109 Police Upfitter 112 Starter Relay
114 Front Windshield Washer
115 Rear Window Washer
116 Cooling Fan Left
121 Right HID Headlamp
122 Left HID Headlamp
123 Cooling Fan Right

Black plate (42,1)Chevrolet 2015i Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-8431502) - 2015 - crc - 1/12/15
10-42 Vehicle Care
Number Usage38 Steering Column Lock 2 (if equipped)
39 Instrument Cluster Battery
40 Not Used
41 Not Used
42 Euro Trailer (if equipped)
43 Left Doors
44 Driver Power Seat
45 Not Used
46 Right Heated/ Cooled Seat
47 Left Heated/ Cooled Seat
48 Not Used
49 Not Used
50 Accessory Power Outlet 2
51 Not Used Number Usage
52 Retained Accessory Power/Accessory
Relay
53 Run/Crank Relay
54 Not Used
55 Not Used
56 Not Used
Instrument Panel Fuse
Block (Right)
The right instrument panel fuse
block access door is on the
passenger side edge of the
instrument panel.
Pull off the cover to access the fuse
block.