2021 CHEVROLET TRAILBLAZER check engine light

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
Driving and Operating 207
braking pressure to any one of the vehicle
wheel brakes to assist the driver in keeping
the vehicle on the intended path.
If cruise control is being used and TCS or
StabiliTrak/ESC begins to limit wheel spin,
cruise control will disengage. Cruise control
may be turned back on when road
conditions allow.
Both systems come on automatically when
the vehicle is started and begins to move.
The systems may be heard or felt while
they are operating or while performing
diagnostic checks. This is normal and does
not mean there is a problem with the
vehicle.
It is recommended to leave both systems on
for normal driving conditions, but it may be
necessary to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow. SeeIf the
Vehicle Is Stuck 0187 and “Turning the
Systems Off and On” later in this section.The indicator light for both systems is in the
instrument cluster. This light will:
.Flash when TCS is limiting wheel spin.
.Flash when StabiliTrak/ESC is activated.
.Turn on and stay on when either system
is not working.
If either system fails to turn on or to
activate, a message displays in the Driver
Information Center (DIC), and
dcomes on
and stays on to indicate that the system is
inactive and is not assisting the driver in
maintaining control. The vehicle is safe to
drive, but driving should be adjusted
accordingly.
If
dcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on and stays
on, the vehicle may need more time to
diagnose the problem. If the condition
persists, see your dealer.
Turning the Systems Off and On
Caution
Do not repeatedly brake or accelerate
heavily when TCS is off. The vehicle
driveline could be damaged.

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
Driving and Operating 233
The fuel door unlocks when the vehicle
doors are unlocked. SeeRemote Keyless
Entry (RKE) System Operation (Key Access)
0 9or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 011.
To open the fuel door, push and release the
rearward center edge of the door.
Turn the fuel cap counterclockwise to
remove. When refueling, hang the fuel cap
from the hook on the fuel door. Fully insert
and latch the fill nozzle, then begin fueling.
{Warning
Overfilling the fuel tank by more than
three clicks of a standard fill nozzle may
cause:
.Vehicle performance issues, including
engine stalling and damage to the fuel
system.
.Fuel spills.
.Under certain conditions, fuel fires.
Be careful not to spill fuel. Wait five seconds
after you have finished pumping before
removing the fill nozzle. Clean fuel from
painted surfaces as soon as possible. See
Exterior Care 0307. Reinstall the cap by
turning it clockwise until it clicks. Push the
fuel door closed until it latches.
{Warning
If a fire starts while you are refueling, do
not remove the fill nozzle. Shut off the
flow of fuel by shutting off the pump or
by notifying the station attendant. Leave
the area immediately.
Caution
If a new fuel cap is needed, get the right
type of cap from your dealer. The wrong
type of fuel cap may not fit properly,
may turn on the malfunction indicator
lamp, and could damage the fuel system
and emissions system. See Malfunction
Indicator Lamp (Check Engine Light) 096.
Filling a Portable Fuel Container
{Warning
Never fill a portable fuel container while
it is in the vehicle. Static electricity
discharge from the container can ignite
the fuel vapor. You or others could be
badly burned and the vehicle could be
damaged. To help avoid injury to you
and others:
.Dispense fuel only into approved
containers.
.Do not fill a container while it is
inside a vehicle, in a vehicle's trunk, in
a pickup bed, or on any surface other
than the ground.
(Continued)

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
Driving and Operating 241
Cross the safety chains under the tongue of
the trailer to help prevent the tongue from
contacting the road if it becomes separated
from the hitch. Always leave just enough
slack so the combination can turn. Never
allow safety chains to drag on the ground.
Trailer Brakes
Loaded trailers over 450 kg (1,000 lb) must
be equipped with brake systems and with
brakes for each axle. Trailer braking
equipment conforming to Canadian
Standards Association (CSA) requirement
CAN3-D313, or its equivalent, is
recommended.
State or local regulations may require
trailers to have their own braking system if
the loaded weight of the trailer exceeds
certain minimums that can vary from state
to state. Read and follow the instructions for
the trailer brakes so they are installed,
adjusted, and maintained properly. Never
attempt to tap into your vehicle's hydraulic
brake system. If you do, both the vehicle
anti-lock brakes and the trailer brakes may
not function, which could result in a crash.
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.
Trailer Tires
Special Trailer (ST) tires differ from vehicle
tires. Trailer tires are designed with stiff
sidewalls to help prevent sway and to
support heavy loads. These features can
make it difficult to determine if the trailer
tire pressures are low only based on a visual
inspection.
Always check all trailer tire pressures before
each trip when the tires are cool. Low trailer
tire pressure is a leading cause of trailer tire
blow-outs.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. See
Malfunction
Indicator Lamp (Check Engine Light) 096.
(Continued)

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
Vehicle Care 243
Vehicle Care
General Information
General Information . . . . . . . . . . . . . . . . . . . 244
California Proposition 65 Warning . . . . . 244
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . . . . . . 244
Accessories and Modifications . . . . . . . . . 245
Vehicle Checks
Doing Your Own Service Work . . . . . . . . 245
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Engine Compartment Overview . . . . . . . . 247
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Engine Oil Life System . . . . . . . . . . . . . . . . . 252
Automatic Transmission Fluid . . . . . . . . . . 252
Engine Air Filter Life System . . . . . . . . . . . 253
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . 253
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 255
Engine Overheating . . . . . . . . . . . . . . . . . . . 258
Washer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
Battery - North America . . . . . . . . . . . . . . . 261
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . 263
Starter Switch Check . . . . . . . . . . . . . . . . . . 263
Automatic Transmission Shift Lock Control Function Check . . . . . . . . . . . . . . 263
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 Wiper Blade Replacement . . . . . . . . . . . . . 264
Windshield Replacement . . . . . . . . . . . . . . 265
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . . . . . . . 266
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . 266
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . 267
LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Headlamps, Front Turn Signal,
Sidemarker, and Parking Lamps (Base
Level) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Headlamps, Front Turn Signal, Sidemarker, and Parking Lamps
(Uplevel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
Taillamps, Turn Signal, Sidemarker, Stoplamps, and Back-Up Lamps (Base
Level) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
Taillamps, Turn Signal, Sidemarker, Stoplamps, and Back-Up Lamps
(Uplevel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Electrical System
Electrical System Overload . . . . . . . . . . . . . 273
Fuses and Circuit Breakers . . . . . . . . . . . . . 274
Engine Compartment Fuse Block . . . . . . 274
Instrument Panel Fuse Block . . . . . . . . . . . 277
Rear Compartment Fuse Block . . . . . . . . . 278
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . 280
Winter Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . . 281
Tire Designations . . . . . . . . . . . . . . . . . . . . . . 282
Tire Terminology and Definitions . . . . . . 283
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 285
Tire Pressure Monitor System . . . . . . . . . 286
Tire Pressure Monitor Operation . . . . . . . 287
Tire Inspection . . . . . . . . . . . . . . . . . . . . . . . . 290
Tire Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . 290
When It Is Time for New Tires . . . . . . . . 291
Buying New Tires . . . . . . . . . . . . . . . . . . . . . 292
Different Size Tires and Wheels . . . . . . . 293
Uniform Tire Quality Grading . . . . . . . . . 293
Wheel Alignment and Tire Balance . . . . 295
Wheel Replacement . . . . . . . . . . . . . . . . . . . 295
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 296
Tire Changing . . . . . . . . . . . . . . . . . . . . . . . . . 297
Compact Spare Tire . . . . . . . . . . . . . . . . . . . . 301
Jump Starting
Jump Starting - North America . . . . . . . . 302
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . . . . . 304
Recreational Vehicle Towing . . . . . . . . . . . 305

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
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260 Vehicle Care
Caution (Continued)
.When using concentrated washer fluid,
follow the manufacturer instructions
for adding water.
.Fill the washer fluid tank only
three-quarters full when it is very cold.
This allows for fluid expansion if
freezing occurs, which could damage
the tank if it is completely full.
Brakes
Disc brake pads have built-in wear indicators
that make a high-pitched warning sound
when the brake pads are worn and new
pads are needed. The sound can come and
go or can be heard all the time when the
vehicle is moving, except when applying the
brake pedal firmly.
{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 0329.
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 4 brake fluid as
indicated on the reservoir cap. See
Engine
Compartment Overview 0247 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.

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
Vehicle Care 303
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 trim cover.
Open 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.
{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.
(Continued)
Warning (Continued)
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 positive (+) terminal on the
discharged battery.
6. Connect the other end of the red positive (+) cable to the positive (+)
terminal of the good battery.
7. Connect one end of the black negative (–) cable to the negative (–)
terminal of the good battery.
8. Connect the other end of the black negative (–) cable to the negative (–)
grounding point for the discharged
battery.

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
310 Vehicle Care
snow and ice. If the check engine light is
activated, please check to see if the shutter
system is clear of debris, snow or ice.
Windshield and Wiper Blades
Clean the outside of the windshield with
glass cleaner.
Clean rubber blades using a lint-free cloth or
paper towel soaked with windshield washer
fluid or a mild detergent. Wash the
windshield thoroughly when cleaning the
blades. Bugs, road grime, sap, and a buildup
of vehicle wash/wax treatments may cause
wiper streaking.
Replace the wiper blades if they are worn or
damaged. Damage can be caused by
extreme dusty conditions, sand, salt, heat,
sun, snow, and ice.
Weatherstrips
Apply weatherstrip lubricant on
weatherstrips to make them last longer, seal
better, and not stick or squeak. Lubricate
weatherstrips at least once a year. Hot, dry
climates may require more frequent
application. Black marks from rubber
material on painted surfaces can be removed
by rubbing with a clean cloth. See
Recommended Fluids and Lubricants0325.
Tires
Use a stiff brush with tire cleaner to clean
the tires.
Caution
Using petroleum-based tire dressing
products on the vehicle may damage the
paint finish and/or tires. When applying a
tire dressing, always wipe off any
overspray from all painted surfaces on
the vehicle.
Wheels and Wheel Trim
Use a soft, clean cloth with mild soap and
water to clean the wheels. After rinsing
thoroughly with clean water, dry with a
soft, clean towel. A wax may then be
applied.
Caution
Chrome wheels and chrome wheel trim
may be damaged if the vehicle is not
washed after driving on roads that have
been sprayed with magnesium chloride or
calcium chloride. These are used on roads
for conditions such as dust and ice.
Always wash the chrome with soap and
water after exposure.
Caution
To avoid surface damage on wheels and
wheel trim, do not use strong soaps,
chemicals, abrasive polishes, cleaners,
or brushes. Use only GM approved
cleaners. Do not drive the vehicle through
an automatic car wash that uses silicon
carbide tire/wheel cleaning brushes.
Damage could occur and the repairs
would not be covered by the vehicle
warranty.
Brake System
Visually inspect brake lines and hoses for
proper attachment, connections, binding,
leaks, cracks, chafing, etc. Inspect disc brake
pads for wear and rotors for surface
condition. Inspect drum brake linings/shoes
for wear or cracks. Inspect all other brake
parts.
Steering, Suspension, and Chassis
Components
Visually inspect steering, suspension, and
chassis components for damaged, loose,
or missing parts or signs of wear at least
once a year.

Chevrolet Trailblazer Owner Manual (GMNA-Localizing-U.S./Canada-
14400528) - 2021 - CRC - 11/7/19
Service and Maintenance 323
.Trained dealer technicians have the
diagnostic equipment to test the battery
and ensure that the connections and
cables are corrosion-free.
Belts
.Belts may need replacing if they squeak
or show signs of cracking or splitting.
.Trained dealer technicians have access to
tools and equipment to inspect the belts
and recommend adjustment or
replacement when necessary.
Brakes
Brakes stop the vehicle and are crucial to
safe driving.
.Signs of brake wear may include chirping,
grinding, or squealing noises, or difficulty
stopping.
.Trained dealer technicians have access to
tools and equipment to inspect the brakes
and recommend quality parts engineered
for the vehicle.
Fluids
Proper fluid levels and approved fluids
protect the vehicle’s systems and
components. See Recommended Fluids and
Lubricants 0325 for GM approved fluids.
.Engine oil and windshield washer fluid
levels should be checked at every fuel fill.
.Instrument cluster lights may come on to
indicate that fluids may be low and need
to be filled.
Hoses
Hoses transport fluids and should be
regularly inspected to ensure that there are
no cracks or leaks. With a multi-point
inspection, your dealer can inspect the hoses
and advise if replacement is needed.
Lamps
Properly working headlamps, taillamps, and
brake lamps are important to see and be
seen on the road.
.Signs that the headlamps need attention
include dimming, failure to light, cracking,
or damage. The brake lamps need to be
checked periodically to ensure that they
light when braking.
.With a multi-point inspection, your dealer
can check the lamps and note any
concerns.
Shocks and Struts
Shocks and struts help aid in control for a
smoother ride.
.Signs of wear may include steering wheel
vibration, bounce/sway while braking,
longer stopping distance, or uneven
tire wear.
.As part of the multi-point inspection,
trained dealer technicians can visually
inspect the shocks and struts for signs of
leaking, blown seals, or damage, and can
advise when service is needed.
Tires
Tires need to be properly inflated, rotated,
and balanced. Maintaining the tires can save
money and fuel, and can reduce the risk of
tire failure.
.Signs that the tires need to be replaced
include three or more visible treadwear
indicators; cord or fabric showing through
the rubber; cracks or cuts in the tread or
sidewall; or a bulge or split in the tire.
.Trained dealer technicians can inspect and
recommend the right tires. Your dealer
can also provide tire/wheel balancing
services to ensure smooth vehicle
operation at all speeds. Your dealer sells
and services name brand tires.