2020 CHEVROLET TAHOE check engine light

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/15/19
138 Instruments and Controls
Malfunctions are often indicated by
the system before any problem is
noticeable. Being aware of the light
and seeking service promptly when
it comes on may prevent damage.
Caution
If the vehicle is driven continually
with this light on, the emission
control system may not work as
well, the fuel economy may be
lower, and the vehicle may not
run smoothly. This could lead to
costly repairs that might not be
covered by the vehicle warranty.
Caution
Modifications to the engine,
transmission, exhaust, intake,
or fuel system, or the use of
replacement tires that do not
meet the original tire
specifications, can cause this light
to come on. This could lead to
costly repairs not covered by the
vehicle warranty. This could also
affect the vehicle’s ability to pass
an Emissions Inspection/
Maintenance test. See
Accessories and Modifications
0285.
If the light is flashing : A
malfunction has been detected that
could damage the emission control
system and increase vehicle
emissions. Diagnosis and service
may be required.
To help prevent damage, reduce
vehicle speed and avoid hard
accelerations and uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as
soon as possible.
If the light continues to flash, find a
safe place to park. Turn the vehicle
off and wait at least 10 seconds
before restarting the engine. If the
light is still flashing, follow the
previous guidelines and see your
dealer for service as soon as
possible.
If the light is on steady :
A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
. If fuel has been added to the
vehicle using the capless funnel
adapter, make sure that it has
been removed. See “Filling the
Tank with a Portable Gas Can”
under Filling the Tank 0259.
The diagnostic system can
detect if the adapter has been
left installed in the vehicle,
allowing fuel to evaporate into

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/15/19
142 Instruments and Controls
This light and the StabiliTrak/ESC
OFF light come on when StabiliTrak/
Electronic Stability Control (ESC) is
turned off.
If the TCS is off, wheel spin is not
limited. Adjust driving accordingly.
SeeTraction Control/Electronic
Stability Control 0229.
StabiliTrak OFF Light
This light comes on briefly while
starting the engine. If it does not,
have the vehicle serviced by your
dealer.
This light comes on when the
StabiliTrak/Electronic Stability
Control (ESC) system is turned off.
If StabiliTrak/ESC is off, the Traction
Control System (TCS) is also off. If StabiliTrak/ESC and TCS are off,
the system does not assist in
controlling the vehicle. Turn on the
TCS and the StabiliTrak/ESC
systems, and the warning light
turns off.
See
Traction Control/Electronic
Stability Control 0229.
Traction Control System
(TCS)/StabiliTrak Light
This light comes on briefly when the
engine is started.
If the light does not come on, have
the vehicle serviced by your dealer.
If the system is working normally,
the indicator light turns off.
If the light is on and not flashing, the
TCS and potentially the StabiliTrak/
ESC system have been disabled.
A Driver Information Center (DIC) message may display. Check the
DIC messages to determine which
feature(s) is no longer functioning
and whether the vehicle requires
service.
If the light is on and flashing, the
TCS and/or the StabiliTrak/ESC
system is actively working.
See
Traction Control/Electronic
Stability Control 0229.
Tire Pressure Light
For vehicles with the Tire Pressure
Monitor System (TPMS), this light
comes on briefly when the engine is
started. It provides information
about tire pressures and the TPMS.
When the Light Is On Steady
This indicates that one or more of
the tires are significantly
underinflated.

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/15/19
Instruments and Controls 143
A Driver Information Center (DIC)
tire pressure message may also
display. Stop as soon as possible,
and inflate the tires to the pressure
value shown on the Tire and
Loading Information label. SeeTire
Pressure 0337.
When the Light Flashes First and
Then Is On Steady
If the light flashes for about a minute
and then stays on, there may be a
problem with the TPMS. If the
problem is not corrected, the light
will come on at every ignition cycle.
See Tire Pressure Monitor
Operation 0340.
Low Fuel Warning Light
This light is near the fuel gauge and
comes on briefly when the ignition is
turned on as a check to show it is
working.
It also comes on when the fuel tank
is low on fuel. The light turns off
when fuel is added. If it does not,
have the vehicle serviced.
Security Light
The security light should come on
briefly as the engine is started. If it
does not come on, have the vehicle
serviced by your dealer. If the
system is working normally, the
indicator light turns off.
If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent system. See
Immobilizer Operation
(Key Access) 035 or
Immobilizer Operation (Keyless
Access) 035.
High-Beam On Light
This light comes on when the
high-beam headlamps are in use.
See Headlamp High/Low-Beam
Changer 0169.
IntelliBeam Light
This light comes on when the
IntelliBeam system, if equipped, is
enabled.

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/24/19
276 Driving and Operating
Trailer Lamps
Always check all trailer lamps are
working at the beginning of each
trip, and periodically on longer trips.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals should will illuminate to
indicate the vehicle is turning,
changing lanes, or stopping. When
towing a trailer, the arrows on the
instrument cluster will illuminate
even if the trailer is not properly
connected or the bulbs are
burned out.
Tow/Haul Mode
For instructions on how to enter
Tow/Haul mode, seeTow/Haul
Mode 0221.
Tow/Haul assists when pulling a
heavy trailer or a large or
heavy load.
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross Combined Weight Rating (GCWR).
See
“Maximum Trailer Weight”
under Trailer Towing 0267.
Tow/Haul Mode is most useful when
towing a heavy trailer or carrying a
large or heavy load:
. through rolling terrain
. in stop-and-go traffic
. in busy parking lots
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage;
however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics
and reduced fuel economy.Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer
brake systems. These instructions
apply to both types of electric trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is proportional to
the amount of vehicle braking. This
available power output to the trailer
brakes can be adjusted to a wide
range of trailering situations.
The ITBC system is integrated with
the vehicle’ s brake, anti-lock brake,
and StabiliTrak systems. In trailering
conditions that cause the vehicle’s
anti-lock brake or StabiliTrak
systems to activate, power sent to
the trailer's brakes will be
automatically adjusted to minimize
trailer wheel lock-up. This does not
imply that the trailer has StabiliTrak.
If the vehicle’s brake, anti-lock
brake, or StabiliTrak systems are
not functioning properly, the ITBC
system may not function fully or at

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/24/19
280 Driving and Operating
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
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
towing. If the vehicle is towing atrailer and the TSC detects that
sway is increasing, the vehicle
brakes are selectively applied at
each wheel, to help reduce
excessive trailer sway. If equipped
with the Integrated Trailer Brake
Control (ITBC) system, and the
trailer has an electric 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. Reduce vehicle
speed by gradually removing your
foot from the accelerator. If trailer
sway continues, StabiliTrak can
reduce engine torque to help slow
the vehicle. TSC will not function if
StabiliTrak is turned off. See
Traction Control/Electronic Stability
Control
0229.
{Warning
Trailer sway can result in a crash
and in serious injury or death,
even if the vehicle is equipped
with TSC.
If the trailer begins to sway,
reduce vehicle speed by
gradually removing your foot from
the accelerator. Then pull over to
check the trailer and vehicle to
help correct possible causes,
including an improperly or
overloaded trailer, unrestrained
cargo, improper trailer hitch
configuration, or improperly
inflated or incorrect vehicle or
trailer tires. See Towing
Equipment 0272 for trailer ratings
and hitch setup
recommendations.

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/24/19
282 Driving and Operating
Trailer tires deteriorate over time.
The trailer tire sidewall will show the
week and year the tire was
manufactured. Many trailer tire
manufacturers recommend
replacing tires more than six
years old.
Overloading is another leading
cause of trailer tire blow-outs. Never
load your trailer with more weight
than the tires are designed to
support. The load rating is located
on the trailer tire sidewall.
Always know the maximum speed
rating for the trailer tires before
driving. This may be significantly
lower than the vehicle tire speed
rating. The speed rating may be on
the trailer tire sidewall. If the speed
rating is not shown, the default
trailer tire speed rating is 105 km/h
(65 mph).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) 0137
. 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 085 and
Adding Equipment to the
Airbag-Equipped Vehicle 085.

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/15/19
Vehicle Care 283
Vehicle Care
General Information
General Information . . . . . . . . . . 284
California Proposition65 Warning . . . . . . . . . . . . . . . . . 285
California Perchlorate Materials Requirements . . . . . 285
Accessories and Modifications . . . . . . . . . . . . . . . . 285
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 286
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 286
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 288
Engine Oil . . . . . . . . . . . . . . . . . . . . 293
Engine Oil Life System . . . . . . . 295
Automatic Transmission Fluid (6-Speed Transmission) . . . . . 296
Automatic Transmission Fluid (10-Speed Transmission) . . . 299
Engine Air Cleaner/Filter . . . . . . 300
Cooling System . . . . . . . . . . . . . . 301
Engine Overheating . . . . . . . . . . 305
Engine Fan . . . . . . . . . . . . . . . . . . . 306
Washer Fluid . . . . . . . . . . . . . . . . . 306
Brakes . . . . . . . . . . . . . . . . . . . . . . . 307 Brake Fluid . . . . . . . . . . . . . . . . . . . 308
Battery - North America . . . . . . 309
Four-Wheel Drive . . . . . . . . . . . . . 310
Front Axle . . . . . . . . . . . . . . . . . . . . 310
Rear Axle . . . . . . . . . . . . . . . . . . . . . 311
Starter Switch Check . . . . . . . . . 311
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 311
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 311
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 312
Wiper Blade Replacement . . . . 312
Glass Replacement . . . . . . . . . . 313
Windshield Replacement . . . . . 313
Gas Strut(s) . . . . . . . . . . . . . . . . . . 314
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 315
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 315
Halogen Bulbs . . . . . . . . . . . . . . . . 315
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 315
LED Lighting . . . . . . . . . . . . . . . . . 315
Headlamps . . . . . . . . . . . . . . . . . . . 316
Fog Lamps . . . . . . . . . . . . . . . . . . . 316
Front Turn Signal Lamps . . . . . 316 Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 317
License Plate Lamp . . . . . . . . . . 318
Electrical System
Electrical System Overload . . . 319
Fuses and Circuit Breakers . . . 319
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 320
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 324
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 327
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 329
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 330
All-Season Tires . . . . . . . . . . . . . . 331
Winter Tires . . . . . . . . . . . . . . . . . . 331
Low-Profile Tires . . . . . . . . . . . . . 332
All-Terrain Tires . . . . . . . . . . . . . . . 332
Tire Sidewall Labeling . . . . . . . . 332
Tire Designations . . . . . . . . . . . . . 333
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 334
Tire Pressure . . . . . . . . . . . . . . . . . 337
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . 338

Chevrolet Tahoe/Suburban Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13566622) - 2020 - CRC - 4/15/19
308 Vehicle Care
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. SeeCapacities and
Specifications 0397.
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
brake fluid as indicated on the
reservoir cap. See
Engine
Compartment Overview 0288 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.
. 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. (Continued)