2021 CHEVROLET COLORADO service

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Instruments and Controls . . . . . . . . . . . . . . . . . 3
Driving and Operating . . . . . . . . . . . . . . . . . . . 13
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Service and Maintenance . . . . . . . . . . . . . . . . 72
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Introduction
The names, logos, emblems, slogans, vehicle
model names, and vehicle body designs
appearing in this manual including, but not
limited to, GM, the GM logo, CHEVROLET,
GMC, the CHEVROLET and GMC Truck
Emblems, COLORADO, CANYON, and
Duramax are trademarks and/or service
marks of General Motors LLC, its
subsidiaries, affiliates, or licensors.
For vehicles first sold in Canada, substitute
the name“General Motors of Canada
Company” for GMC and Chevrolet Motor
Division wherever they appear in this
manual.
This manual describes features that may or
may not be on the vehicle because of
optional equipment that was not purchased
on the vehicle, model variants, country
specifications, features/applications that may
not be available in your region, or changes
subsequent to the printing of this owner’s
manual.
Refer to the purchase documentation
relating to your specific vehicle to confirm
the features. This manual contains information that
pertains to the operation of the diesel
engine. It also contains the Diesel
Maintenance Schedule. The sections in this
manual correspond to the sections in the
owner’s manual. This manual, along with
the owner’s manual, will assist you in the
proper use and maintenance of the vehicle.
Keep this manual in the vehicle for quick
reference.
Canadian Vehicle Owners
A French language manual can be obtained
from your dealer, at www.helminc.com,
or from:
Propriétaires Canadiens
On peut obtenir un exemplaire de ce guide
en français auprès du concessionnaire ou à
l'adresse suivante:
Helm, Incorporated
Attention: Customer Service
47911 Halyard Drive
Plymouth, MI 48170
USA
Litho in U.S.A.
Part No. 84267010 A First Printing©2020 General Motors LLC. All Rights Reserved.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
8 Instruments and Controls
the tank was half full, but it actually took
a little more or less than half the tank's
capacity to fill the tank.
.The gauge moves a little while turning a
corner or speeding up.
.The gauge does not go back to E (Empty)
when the ignition is turned off.
None of these indicate a problem with the
fuel gauge.
For information on how to fill the fuel tank,
see Filling the Tank 032.
Engine Oil Pressure Gauge
4-Cylinder Pickup Models
See “Oil Pressure” under“Driver Information
Center (DIC)” in the owner’s manual.
Metric Van Models
English Van Models
Caution
Lack of proper engine oil maintenance
can damage the engine. Driving with the
engine oil low can also damage the
engine. The repairs would not be covered
by the vehicle warranty. Check the oil
level as soon as possible. Add oil if
required, but if the oil level is within the
operating range and the oil pressure is
still low, have the vehicle serviced.
Always follow the maintenance schedule
for changing engine oil.
The engine oil pressure gauge reads in kPa
(kilopascals) or psi (pounds per square inch)
when the engine is running. Oil pressure
may vary with engine speed, outside
temperature, and oil viscosity.
If readings are outside the normal operating
range, the low oil pressure message may
display on the Driver Information Center
(DIC), or for vehicles without a DIC the oil
pressure light will come on. If the oil
pressure message or light comes on, check
the oil level immediately. Do not operate
the engine with the oil pressure warning
light on or an ENGINE OIL LOW ADD OIL
message displayed.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Instruments and Controls 9
Malfunction Indicator Lamp
(Check Engine Light)
This light is part of the vehicle’s emission
control on-board diagnostic system. If this
light is on while the engine is running, a
malfunction has been detected and the
vehicle may require service. The light should
come on to show that it is working when
the ignition is on with the engine not
running. See“Ignition Positions” in the
owner’s manual.
This light may also come on when the
system has detected a problem with the
Diesel Exhaust Fluid (DEF) management
system. See Diesel Exhaust Fluid 022.
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 052.
When the light is on, a malfunction has
been detected. Diagnosis and service may be
required.
Poor fuel quality can cause inefficient engine
operation and poor driveability, which may
go away once the engine is warmed up. If this occurs, change the fuel brand. It may
require at least one full tank of the proper
fuel to turn the light off. See
Fuel for Diesel
Engines 025.
If the light remains on, see your dealer.
Emissions Inspection and Maintenance
Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).
The DLC is under the instrument panel to
the left of the steering wheel. Connecting
devices that are not used to perform an
Emissions Inspection/Maintenance test or to
service the vehicle may affect vehicle
operation. See “Add-On Electrical Equipment”
in the owner’s manual. See your dealer if
assistance is needed.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
10 Instruments and Controls
The vehicle may not pass inspection if:
.The light is on when the engine is
running.
.The light does not come on when the
ignition is on with the engine not
running.
.Critical emission control systems have not
been completely diagnosed. If this
happens, the vehicle would not be ready
for inspection and might require
several days of routine driving before the
system is ready for inspection. This can
happen if the 12-volt battery has recently
been replaced or run down, or if the
vehicle has recently been serviced.
See your dealer if the vehicle will not pass
or cannot be made ready for the test.
Wait-to-Start Light
This light comes on briefly while starting
the engine, as a check to show the light is
working. If the wait-to-start light comes on, the glow
plug system is required and operating. Wait
until the light turns off before starting the
engine. This light may not come on in warm
temperatures.
The fast warm-up glow plug system makes
the wait-to-start light stay on for a shorter
amount of time than most diesel engines.
See
Starting the Diesel Engine 013.
Diesel Exhaust Fluid (DEF)
Warning Light
This light, a Driver Information Center (DIC)
message, and a chime come on when there
is an issue with the Diesel Exhaust Fluid.
If the DEF level has not been corrected, the
light will continue to flash when the vehicle
is started. The vehicle's speed may also be
limited.
Also see Diesel Exhaust Fluid 022.
Power Take-Off Light (Chassis
Cab Only)
Chassis Cab
The vehicle may have a Power Take-Off
(PTO) light. Under normal operating
conditions, the PTO light will remain on
throughout the PTO operating cycle. If all
conditions required to engage PTO have not
been met when enabling PTO, the PTO light
will turn on, then turn off after one second.
See Power Take-Off (PTO) 037.
Information Displays
Driver Information Center (DIC)
The DIC is in the instrument cluster. The DIC
comes on when the ignition is on.
A Duramax diesel vehicle may have the
following additional DIC menu items:

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
14 Driving and Operating
Observe the wait-to-start light. See
Wait-to-Start Light010. This light may
not come on if the engine is warm.
2. If the wait-to-start light is on, wait until this light goes off. Turn the ignition key
to START, then release the ignition key.
The engine will continue to crank until
the engine starts.
The engine has a fast warm-up glow
plug system. The wait-to-start light will
illuminate for a much shorter time than
most diesel engines, due to the rapid
heating of the glow plug system.
Caution
If the wait-to-start light stays on after
starting the vehicle, the vehicle may not
run properly. Have the vehicle serviced
right away.
3. If the engine does not start after 15 seconds of cranking, turn the ignition
off. Wait one minute for the cranking
motor to cool, then try the same steps
again.
If you are trying to start the engine after
you have run out of fuel, follow the steps in
Running Out of Fuel 030. When the engine is cold, let it run for a few
minutes before driving. This lets oil pressure
build up. The engine will sound louder when
it is cold.
For turbo protection, engine power at
speeds above idle may be limited if the
engine is cold. This protection can last up to
a maximum of 40 seconds at extreme cold
coolant and ambient temperatures.
Cold Weather Starting
Use the recommended engine oil when the
outside temperature drops below freezing.
See
Engine Oil 055. When the outside
temperature drops below –18 °C (0 °F), use
of the engine coolant heater is
recommended.
If you experience longer cranking times,
notice an unusual amount of exhaust smoke,
or are at higher elevations (over 2 135 m or
7,000 ft), you may use the engine coolant
heater. See Engine Heater 017.
See Fuel for Diesel Engines 025 for
information on what fuel to use in cold
weather.
If the Diesel Engine Will Not Start
If the vehicle runs out of fuel, see Running
Out of Fuel 030. If the vehicle is not out of fuel, and the
engine will not start:
Turn the ignition key to ON/RUN. After the
wait-to-start light goes off, turn the ignition
key to START.
If the light does not go off, wait a few
seconds, then try starting the engine again.
See your dealer as soon as possible for a
starting system check.
If the light comes on and then goes off and
you know the batteries are charged, but the
engine still will not start, the vehicle needs
service.
If the light does not come on when the
engine is cold, the vehicle needs service.
If the batteries do not have enough charge
to start the engine, see
“Battery”in the
owner’s manual.
Check that the correct engine oil has been
used and changed at appropriate intervals.
If the wrong oil is used, the engine may be
harder to start.
Be sure you are using the proper fuel for
existing weather conditions. See Fuel for
Diesel Engines 025.
If the engine starts, runs a short time, then
stops, the vehicle needs service.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
20 Driving and Operating
Caution (Continued)
Recommended Fluids and Lubricants
section of this manual are not used. This
damage would not be covered by the
vehicle warranty.
Under certain driving conditions, such as
stop-and-go traffic, the filter cannot clean
itself. A message comes on when the DPF is
dirty and needs to perform a self cleaning.
For the filter to clean itself, the vehicle must
be driven above 50 km/h (30 mph) until the
message goes off. This will take about
30 minutes.
{Warning
During DPF self-cleaning or during
extended idling in P (Park), the exhaust
system and exhaust gases are very hot.
Things that burn could touch hot exhaust
parts under the vehicle and ignite. You or
others could be burned. Do not park,
or idle for an extended period of time,
near or over papers, leaves, dry grass,
or other things that can burn. Keep the (Continued)
Warning (Continued)
exhaust area clear of material that could
ignite or burn. SeeParking over Things
That Burn 019.
Caution
Extended idle should be avoided because
the DPF system is not capable of self
cleaning at idle. During extended idle
operation, monitor the instrument cluster
telltale lights and Driver Information
Center for messages and take appropriate
indicated action. Continued idling with
the warning light/message on could
cause irreversible damage to the DPF
requiring repair and possible replacement
that might not be covered by the vehicle
warranty.
You will also notice a change in the exhaust
sound and engine idle speed. Along with
this, a burning smell and reduction in fuel
economy may be noticed. This is normal.
If you continue to drive with the DPF
warning message on and the exhaust filter
is not cleaned as required, the malfunction
indicator lamp and the ENGINE POWER IS REDUCED message will come on and dealer
service is necessary. See
Malfunction
Indicator Lamp (Check Engine Light) 09.
Vehicles with the DPF have specific fuel and
engine oil requirements. See Fuel for Diesel
Engines 025 and
Engine Oil 055.
Extended idling in P (Park) can cause exhaust
parts and gases to become very hot. Keep
the exhaust area clear of material that could
ignite or burn. See Parking over Things That
Burn 019.
If equipped with Power Take-Off (PTO),
monitor the instrument cluster for lights
related to the DPF.
See Accessories and Modifications 052 for
important information if you are considering
adding accessories or modifying the vehicle.
Manual Regeneration of Diesel
Particulate Filter
This feature is only available on Fleet and
Commercial vehicles.
To verify that the vehicle has this feature,
refer to the Vehicle Service Parts
Identification label (SPID) for RPO code FPF

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
22 Driving and Operating
Continue to follow the instructions in the
DIC messages. Hold the exhaust brake
switch on the center stack below the climate
controls for more than three seconds, and
then release it, to begin the regeneration
process.
If the EXHAUST BRAKE ON message displays,
then the switch was released too soon.
Press it again to turn off the exhaust brake,
then try again when the DIC message
prompts.
When manual regeneration begins, the
engine speed increases, the engine cooling
fan sound increases, and a DIC message
indicates that cleaning is in progress.
A DIC message will display when cleaning
has completed. The message will remain as
long as cleaning is not necessary. Cleaning
could take up to 30 minutes. Upon
completion, the engine will return to normal
idle, but exhaust components will remain
hot for several minutes. Do not move the
vehicle until the exhaust has had time to
cool. Manual regeneration can be canceled
at any time by pressing the brake pedal or
turning the engine off. Unusual noises may
be heard if regeneration is interrupted.Diesel Exhaust Fluid{
Warning
Avoid getting Diesel Exhaust Fluid (DEF)
on your skin or in your eyes as it could
cause irritation. For more safety,
handling, and storage information, see
the Diesel Exhaust Fluid container label.
Caution
Use only DEF that is GM approved,
or fluid containing the API certified or ISO
22241 label. The use of other fluids could
damage the system, requiring costly
repairs that will not be covered by the
vehicle warranty.
Caution
Do not mix fuel with DEF, and do not put
DEF in the fuel tank. This could lead to
costly repairs that might not be covered
by the vehicle warranty.
Diesel Exhaust Fluid (DEF) is used with diesel
engines to reduce the amount of regulated
emissions produced. Products such as AdBlue are types of DEF, and are approved for use
in the vehicle as long as they have an API
certification label or meet ISO 22241. The
fluid level in the DEF tank must be
maintained for the vehicle to run properly.
DEF is not a fuel additive. DEF should not be
mixed with or added to diesel fuel. DEF
freezes when exposed to temperatures
below
−11 °C (12 °F). For DEF tank capacity
see Capacities and Specifications 082.
It is normal to hear the DEF system purge
fluid back into the tank after the vehicle is
shut off.
Locating Diesel Exhaust Fluid
DEF can be purchased at your dealer.
Additionally, some diesel truck fueling
stations or retailers may have DEF for
purchase. For vehicles with an active OnStar
or connected services plan, OnStar can help
to locate a DEF retailer. See “Customer
Assistance Offices” in the owner’s manual
for phone numbers to assist in contacting a
GM dealer. See Recommended Fluids and
Lubricants 078.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
24 Driving and Operating
limited. For the DEF warning light symbol,
seeDiesel Exhaust Fluid (DEF) Warning Light
0 10.
DEF Quality Poor
Use only DEF that is GM approved, or fluid
containing the API certified or ISO 22241
label.
DEF has an expiration date. If the system
detects poor quality, or contaminated or
diluted DEF, the DIC message will display
along with distance until vehicle speed is
limited.
The speed limitation will occur in a series of
steps with the final speed limitation being
8 km/h (5 mph) along with a flashing
warning light and chimes.
Adding fresh DEF to the system may resolve
the problem after several kilometers/miles
of driving, depending on several factors.
If the DIC message persists, see your dealer
or additional DIC messages may display.
Service DEF System
If a problem occurs with the DEF system, a
DIC message displays along with distance
until vehicle speed is limited. The speed limitation will occur in a series of
steps with the final speed limitation being
8 km/h (5 mph) along with a flashing
warning light and chimes.
In some cases, this message will clear itself,
indicating that the DEF system was able to
correct the condition. If the DIC message
persists, see your dealer or additional DIC
messages may display.
Service Emission System
If a problem occurs with the vehicle
emission system, a DIC message displays
along with distance until vehicle speed is
limited. The speed limitation will occur in a
series of steps with the final speed
limitation of 88 km/h (55 mph) and chimes.
In some cases, this message will clear itself,
indicating that the emission system was
able to correct the condition. If the DIC
message persists, see your dealer or
additional DIC messages may display.
Brakes
Exhaust Brake
The exhaust brake can be used to enhance
the vehicle brake system and reduce brake
lining wear.Downshifts may be automatically selected
to increase engine speed, which increases
the effectiveness of the exhaust brake. The
number of downshifts selected is
determined by the length of time the brakes
are applied and the rate the vehicle is
slowing. The system delivers the correct
amount of braking to assist in vehicle
control. The heavier the vehicle load, the
more active the engine exhaust brake will
be. Use of the exhaust brake will help
maintain vehicle speed when used with
cruise control. See
“Cruise Control”in the
owner’s manual.
Automatic downshifts will not occur if the
vehicle is in Range Selection Mode. See
“Manual Mode” in the owner’s manual.
The exhaust brake only activates when the
transmission torque converter is locked. This
can vary based on vehicle speed, gear,
and load.
To activate the system, press the switch on
the center stack.