2021 CHEVROLET BLAZER ECU

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
200 Driving and Operating
The Certification/Tire label may also
show the maximum weights for the
front and rear axles, called the Gross
Axle Weight Rating (GAWR). To find out
the actual loads on the front and rear
axles, weigh the vehicle at a weigh
station. Your dealer can help with this.
Be sure to spread the load equally on
both sides of the centerline.Caution
Overloading the vehicle may cause
damage. Repairs would not be covered by
the vehicle warranty. Do not overload the
vehicle.
{Warning
Things inside the vehicle can strike
and injure people in a sudden stop or
turn, or in a crash.
.Put things in the cargo area of the
vehicle. In the cargo area, put
them as far forward as possible.
Try to spread the weight evenly.
(Continued)
Warning (Continued)
.Never stack heavier things, like
suitcases, inside the vehicle so
that some of them are above the
tops of the seats.
.Do not leave an unsecured child
restraint in the vehicle.
.Secure loose items in the vehicle.
.Do not leave a seat folded down
unless needed.
Starting and Operating
New Vehicle Break-In
Caution
The vehicle does not need an elaborate
break-in. But it will perform better in the
long run if you follow these guidelines:
.Do not drive at any one constant
speed, fast or slow, for the first
800 km (500 mi). Do not make
full-throttle starts. Avoid downshifting
to brake or slow the vehicle.
(Continued)
Caution (Continued)
.Avoid making hard stops for the first
300 km (200 mi) or so. During this
time the new brake linings are not yet
broken in. Hard stops with new linings
can mean premature wear and earlier
replacement. Follow this breaking-in
guideline every time you get new
brake linings.
Following break-in, engine speed and load
can be gradually increased.
Ignition Positions
This vehicle has pushbutton starting.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Driving and Operating 243
If the transmission downshifts too often,
a lower gear may be selected using
Manual Mode. SeeManual Mode0209.
If equipped, Driver Assistance Systems must
be turned off when towing a trailer:
.Adaptive Cruise Control (ACC)
.Lane Keep Assist (LKA)
.Park Assist
.Reverse Automatic Braking (RAB)
If equipped, the following driver assistance
features should be turned to alert or off
when towing a trailer:
.Automatic Emergency Braking (AEB)
.Intelligent Brake Assist (IBA)
.Front Pedestrian Braking (FPB)
If equipped with Lane Change Alert (LCA),
the LCA detection zones that extend back
from the side of the vehicle do not move
further back when a trailer is towed. Use
caution while changing lanes when towing a
trailer.
If equipped with Rear Cross Traffic Alert
(RCTA), use caution while backing up when
towing a trailer, as the RCTA detection zones
that extend out from the back of the vehicle
do not move further back when a trailer is
towed.
{Warning
To prevent serious injury or death from
carbon monoxide (CO), when towing a
trailer:
.Do not drive with the liftgate, trunk/
hatch, or rear-most window open.
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to a
setting that brings in only outside air.
See “Climate Control Systems” in the
Index.
For more information about carbon
monoxide, see Engine Exhaust 0207.
Towing a trailer requires experience. The
combination of the vehicle and trailer is
longer and not as responsive as the vehicle
itself. Get used to the handling and braking
of the combination by driving on a level
road surface before driving on public roads.
The trailer structure, the tires, and the
brakes must all be rated to carry the
intended cargo. Inadequate trailer
equipment can cause the combination to
operate in an unexpected or unsafe manner. Before driving, inspect all trailer hitch parts
and attachments, safety chains, electrical
connectors, lamps, tires, and mirrors. See
Towing Equipment
0248. If the trailer has
electric brakes, start the combination
moving and then manually apply the trailer
brake controller to check that the trailer
brakes work.
During the trip, occasionally check that the
cargo and trailer are secure and that the
lamps and any trailer brakes are working.
Towing with a Stability Control System
When towing, the stability control system
might be heard. The system reacts to
vehicle movement caused by the trailer,
which mainly occurs during cornering. This is
normal when towing heavier trailers.
Following Distance
Stay at least twice as far behind the vehicle
ahead as you would when driving without a
trailer. This can help to avoid heavy braking
and sudden turns.
Passing
More passing distance is needed when
towing a trailer. The combination of the
vehicle and trailer will not accelerate as
quickly and is much longer than the vehicle

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Vehicle Care 271
6. Verify coolant level after the engine isshut off and the coolant is cold.
If necessary, repeat coolant fill procedure
Steps 1–6.
If the coolant still is not at the proper
level when the system cools down again,
see your dealer.
Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
2.0L L4 Engine Only - Automatic Coolant
Service Fill Instructions
If equipped, this feature assists in filling and
removing air from the cooling system after
service of components or when coolant is
added after being too low.
To activate the fill and air removal process:
1. With a cold system, add coolant to the indicated mark on the surge tank.
2. Replace the cap on the surge tank.
3. Connect the vehicle to a battery charger.
4. Turn the ignition to Service Mode. See Ignition Positions 0200. 5. Turn off the air conditioning.
6. Set the parking brake.
7. At the same time, press the accelerator
and the brake for two seconds, then
release.
At the end of the cycle, check the coolant
level in the surge tank and add coolant if it
is low. Turn off the vehicle, allow the
Electronic Control Module (ECM) to go to
sleep, about two minutes, and repeat
Steps 4–7.
Listen for pump activation and movement of
the control valves while watching the level
of the coolant in the surge tank. If the tank
empties, turn the ignition off, carefully
remove the surge tank cap, refill to the
indicated mark, and repeat Steps 4–7. The
fill and air removal process will run for
approximately 10 minutes.
Engine Overheating
The vehicle has several indicators to warn of
the engine overheating.
There is an engine coolant temperature
gauge on the instrument cluster. See Engine
Coolant Temperature Gauge 096. 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 Assistance Program
0 352.
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 (Continued)

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14608203) - 2021 - CRC - 10/29/20
276 Vehicle Care
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 replaced
periodically. See Maintenance Schedule
0 332.
Replacement blades come in different types
and are removed in different ways. For
proper type and length, see Maintenance
Replacement Parts 0341.
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.
Front Wiper Blade Replacement
To replace the wiper blade:
1. Pull the wiper assembly away from the windshield.
2. Lift up on the latch in the middle of thewiper 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.
5. Reverse Steps 1–3 for wiper blade replacement.
Rear Wiper Blade Replacement
The rear wiper blade and wiper arm have a
cover for protection.
To remove the cover:
1. Slide a plastic tool under the cover andpush upward to unsnap.
2. Slide the cover toward the wiper blade tip to unhook it from the blade
assembly.
3. Remove the cover.
4. After wiper blade replacement, ensure that the cover hook slides into the slot
in the blade assembly.
5. Snap the cover down to secure.
To replace the wiper blade: 1. Lift the wiper arm away from the windshield.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Vehicle Care 277
2. Push the release lever (2) to disengagethe hook and push the wiper arm (1) out
of the blade assembly (3).
3. Push the new blade assembly securely on the wiper arm until the release lever
clicks into place.
Windshield Replacement
Driver Assistance Systems
If the windshield needs to be replaced and
the vehicle is equipped with a front camera
sensor for the Driver Assistance Systems, a
GM replacement windshield is
recommended. The replacement windshield
must be installed according to GM
specifications for proper alignment. If it is
not, these systems may not work properly,
they may display messages, or they may
not work at all. See your dealer for proper
windshield replacement.
Gas Strut(s)
This vehicle is equipped with gas strut(s) to
provide assistance in lifting and holding
open the hood/trunk/liftgate system in full
open position.
{Warning
If the gas struts that hold open the hood,
trunk, and/or liftgate fail, you or others
could be seriously injured. Take the
vehicle to your dealer for service
immediately. Visually inspect the gas
struts for signs of wear, cracks, or other
damage periodically. Check to make sure
the hood/trunk/liftgate is held open with
enough force. If struts are failing to hold
the hood/trunk/liftgate, do not operate.
Have the vehicle serviced.
Caution
Do not apply tape or hang any objects
from gas struts. Also do not push down
or pull on gas struts. This may cause
damage to the vehicle.
See Maintenance Schedule 0332.
Hood
Trunk

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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306 Vehicle Care
Warning (Continued)
traction device if it contacts the vehicle.
Do not spin the wheels. If traction
devices are used, install them on the
front tires.
Caution
If the vehicle is equipped with a tire size
other than 235/55R20 or 265/45R21 use
tire chains only where legal and only
when necessary. Use low profile chains
that add no more than 12 mm thickness
to the tire tread and inner sidewall. Use
chains that are the proper size for the
tires. Install them on the tires of the
front axle. Do not use chains on the tires
of the rear axle. Tighten them as tightly
as possible with the ends securely
fastened. Drive slowly and follow the
chain manufacturer's instructions. If the
chains contact the vehicle, stop and
retighten them. If the contact continues,
slow down until it stops. Driving too fast
or spinning the wheels with chains on
will damage the vehicle.
If a Tire Goes Flat
It is unusual for a tire to blow out while
driving, especially if the tires are maintained
properly. SeeTires0287. If air goes out of a
tire, it is much more likely to leak out
slowly. But if there is ever a blowout, here
are a few tips about what to expect and
what to do:
If a front tire fails, the flat tire creates a
drag that pulls the vehicle toward that side.
Take your foot off the accelerator pedal and
grip the steering wheel firmly. Steer to
maintain lane position, and then gently
brake to a stop, well off the road,
if possible.
A rear blowout, particularly on a curve, acts
much like a skid and may require the same
correction as used in a skid. Stop pressing
the accelerator pedal and steer to straighten
the vehicle. It may be very bumpy and
noisy. Gently brake to a stop, well off the
road, if possible.
{Warning
Driving on a flat tire will cause
permanent damage to the tire.
Re-inflating a tire after it has been driven
(Continued)
Warning (Continued)
on while severely underinflated or flat
may cause a blowout and a serious crash.
Never attempt to re-inflate a tire that has
been driven on while severely
underinflated or flat. Have your dealer or
an authorized tire service center repair or
replace the flat tire as soon as possible.
{Warning
Lifting a vehicle and getting under it to
do maintenance or repairs is dangerous
without the appropriate safety equipment
and training. If a jack is provided with
the vehicle, it is designed only for
changing a flat tire. If it is used for
anything else, you or others could be
badly injured or killed if the vehicle slips
off the jack. If a jack is provided with the
vehicle, only use it for changing a
flat tire.
If a tire goes flat, avoid further tire and
wheel damage by driving slowly to a level
place, well off the road, if possible. Turn on
the hazard warning flashers. See Hazard
Warning Flashers 0124.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Vehicle Care 317
4. Place the loop end of the strap throughthe cargo tie-down. Place the hook end
of the strap through the loop and pull it
until the strap is fastened securely to
the tie-down.5. Route the strap hook through the wheel,as shown.
6. Attach the strap to the other cargo tie-down in the rear of the vehicle.
7. Tighten the strap and secure it using the buckle.
The compact spare is for temporary use
only. Replace the compact spare tire with a
full-size tire as soon as you can.
Compact Spare Tire
{Warning
Driving with more than one compact
spare tire at a time could result in loss of
braking and handling. This could lead to a
crash and you or others could be injured.
Use only one compact spare tire at
a time.
If this vehicle has a compact spare tire, it
was fully inflated when new; however, it
can lose air over time. Check the inflation
pressure regularly. It should be 420 kPa
(60 psi).
Stop as soon as possible and check that the
spare tire is correctly inflated after being
installed on the vehicle. The compact spare
tire is designed for temporary use only. The
vehicle will perform differently with the
spare tire installed and it is recommended
that the vehicle speed be limited to 80 km/h
(50 mph). To conserve the tread of the spare
tire, have the standard tire repaired or
replaced as soon as convenient and return
the spare tire to the storage area.

Chevrolet Blazer Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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320 Vehicle Care
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 remote
negative (–) terminal for the discharged
battery.
9. Start the engine in the vehicle with the good battery and run the engine at idle
speed for at least four minutes.
10. Try to start the vehicle that had the dead battery. If it will not start after a
few tries, it probably needs service.
Caution
If the jumper cables are connected or
removed in the wrong order, electrical
shorting may occur and damage the
vehicle. The repairs would not be covered
by the vehicle warranty. Always connect
(Continued)
Caution (Continued)
and remove the jumper cables in the
correct order, making sure that the cables
do not touch each other or other metal.
Jumper Cable Removal
Reverse the sequence exactly when
removing the jumper cables.
After starting the disabled vehicle and
removing the jumper cables, allow it to idle
for several minutes.
Towing the Vehicle
Caution
Incorrectly towing a disabled vehicle may
cause damage. The damage would not be
covered by the vehicle warranty. Do not
lash or hook to suspension components.
Use the proper straps around the tires to
secure the vehicle. Do not drag a locked
wheel/tire. Use tire skates or dollies
under any locked wheel/tire while
loading the vehicle. Do not use a sling
type lift to tow the vehicle. This could
damage the vehicle.
Caution
Improper use of the tow eye can damage
the vehicle. If equipped, use the tow eye
to load a disabled vehicle onto a flatbed
tow truck from a flat road surface, or to
move the vehicle a short distance. Use
caution and low speeds. The transmission
must be in (N) Neutral when moving the
vehicle.
GM recommends a flatbed tow truck to
transport a disabled vehicle. Use ramps to
help reduce approach angles, if necessary.
A towed vehicle should have its drive wheels
off the ground. Contact Roadside Assistance
or a professional towing service if the
disabled vehicle must be towed.