GMC 2.8L Duramax Diesel 2020 User manual

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20_MUL_2.8L_Duramax_Diesel_Engline_Supplement__COV_en_US_84186892A_2019MAY16.ai 1 5/16/2019 8:20:14 AM20_MUL_2.8L_Duramax_Diesel_Engline_Supplement__COV_en_US_84186892A_2019MAY16.ai 1 5/16/2019 8:20:14 AM

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Contents Introduction . . . . . . . . . . . . . . . . . . . . . . 2
Instruments and Controls . . . . . . . . 5
Driving and Operating . . . . . . . . . . 16
Vehicle Care . . . . . . . . . . . . . . . . . . . . 64
Service and Maintenance . . . . . . . 88
Technical Data . . . . . . . . . . . . . . . . . 96
Index .................... 100

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
2 Introduction
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
Using this Supplement
This supplement contains
information specific to the unique
components of the vehicle. It does
not explain everything you need to
know about the vehicle. Read this
supplement along with the owner’s
manual to learn about the vehicle's
features and controls.
Litho in U.S.A.
Part No. 84186892 A First Printing ©2019 General Motors LLC. All Rights Reserved.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Introduction 3
Index
A good place to look for what you
need is the Index in the back of this
supplement. It is an alphabetical list
of what is in the supplement, and
the page number where you will
find it.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
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4 Introduction
2NOTES

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Instruments and Controls 5
Instruments and
Controls
Warning Lights, Gauges, and
Indicators
Instrument Cluster . . . . . . . . . . . . . . 6
Fuel Gauge ..................... 9
Engine Oil Pressure Gauge . . . . 10
Malfunction Indicator Lamp
(Check Engine Light) . . . . . . . . . 11
Wait-to-Start Light . . . . . . . . . . . . . 12
Diesel Exhaust Fluid (DEF)
Warning Light . . . . . . . . . . . . . . . . 13
Power Take-Off Light (Chassis
Cab Only) . . . . . . . . . . . . . . . . . . . . 13
Information Displays
Driver Information
Center (DIC) . . . . . . . . . . . . . . . . . 13
Vehicle Personalization
Vehicle Personalization (Van
Models) . . . . . . . . . . . . . . . . . . . . . . 14
Vehicle Personalization (Pickup
Models) . . . . . . . . . . . . . . . . . . . . . . 14

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
6 Instruments and Controls
Warning Lights, Gauges, and Indicators
Instrument Cluster
English Base Level 4-Cylinder Pickup Shown, Metric Similar

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Instruments and Controls 7
English Uplevel 4-Cylinder Pickup Shown, Metric Similar

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
8 Instruments and Controls
English Van Shown, Metric Similar

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Instruments and Controls 9
See the owner’s manual for warning
lights and gauges not listed in this
supplement.
Fuel Gauge
Metric Base Level 4-Cylinder
Pickup Shown, Uplevel Similar
English Base Level 4-Cylinder
Pickup Shown, Uplevel Similar
Metric Van Models
English Van Models
When the ignition is on, the fuel
gauge shows approximately how
much fuel the vehicle has left in the
tank. The gauge will first indicate
E (Empty) before the vehicle is out
of fuel, but the vehicle's fuel tank
should be filled soon.
An arrow on the fuel gauge
indicates the side of the vehicle the
fuel door is on.
Listed are four situations customers
may experience with the fuel gauge:
.At the gas station, the fuel pump
shuts off before the gauge reads
F (Full).

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
10 Instruments and Controls
.It takes a little more or less fuel
to fill up than the fuel gauge
indicated. For example, the
gauge may have indicated 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 040.
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

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Instruments and Controls 11
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.
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 027.
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
064.
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 032.

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12 Instruments and Controls
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.
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 016.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
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Instruments and Controls 13
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 027.
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) 046.
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:
Exhaust Fluid Level : The Diesel
Exhaust Fluid (DEF) level will be
displayed as either OK, XX%,
or LOW.
When LOW appears on the display,
add DEF as soon as possible. See
Diesel Exhaust Fluid 027.
Fuel Filter Life Remaining : This
display shows an estimate of the
fuel filter's remaining useful life.
If 90% Fuel Filter Life Remaining is
displayed, it means 90% of the
current fuel filter life remains. The
fuel filter life system will alert when
to change the fuel filter on a
schedule consistent with your
driving conditions.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
14 Instruments and Controls
When the remaining fuel filter life is
low, the CHANGE FUEL FILTER
message will appear on the display.
Change the fuel filter as soon as
possible.
Fuel Filter Life Reset : Reset the
Fuel Filter Life Remaining display
after each fuel filter change. It will
not reset itself. Also, be careful not
to reset the display at any time other
than when the fuel filter has just
been changed because it cannot be
reset accurately until the next fuel
filter change. The fuel filter life will
change to 100% when the system
has been reset. To reset the system,
press and hold the set/reset button,
or the trip odometer reset stem if
there are no DIC buttons, for
two seconds while Fuel Filter Life
Remaining is displayed on the DIC.
Engine Hour (Hourmeter) : Shows
the total number of hours the engine
has run. The display also shows the
engine idle hours.
Vehicle
Personalization
Vehicle Personalization
(Van Models)
This vehicle may have
customization capabilities that allow
you to program certain features to
one preferred setting. Customization
features can only be programmed to
one setting on the vehicle and
cannot be programmed to a
preferred setting for two different
drivers.
A Duramax diesel vehicle may have
the following additional vehicle
personalization items:
Feature Settings Menu Items
The following are customization
features that allow you to program
settings to the vehicle:
ELEVATED IDLE
This feature allows you to turn on or
off Elevated Idle.
Press Uuntil ELEVATED IDLE
appears on the DIC display.
Press Vonce to access the settings
for this feature. Then press Uto
scroll through OFF, ON, or NO
CHANGE. To select a setting, press
Vwhile the desired setting is
displayed on the DIC.
Vehicle Personalization
(Pickup Models)
Use the audio system controls to
access the personalization menus
for customizing vehicle features.
The following features may be
available on some vehicles with a
diesel engine. See “Vehicle
Personalization”in the owner’s
manual for additional vehicle
personalizations.
If equipped, these features may be
selected using the infotainment
display.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
Instruments and Controls 15
To access the vehicle
personalization menu:
1. Touch the Settings icon on the
Home Page of the infotainment
display.
2. Touch Vehicle to display a list
of available options.
3. Touch to select the desired
feature setting.
4. Touch 9or Rto turn a feature
off or on.
5. Touch zto go to the top level
of the Settings menu.
Climate and Air Quality
Select and the following may
display:
Rapid Heat-Elevated Idle
This allows the feature to be turned
on and off. See “Elevated Idle”in
Starting the Diesel Engine 016.
Select Off or On.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
16 Driving and Operating
Driving and
Operating
Starting and Operating
Starting the Diesel Engine . . . . . 16
Winter Cover . . . . . . . . . . . . . . . . . . . 19
Engine Heater . . . . . . . . . . . . . . . . . 21
Fuel Operated Heater (FOH)
(Van Models Only) . . . . . . . . . . . 23
Parking over Things
That Burn . . . . . . . . . . . . . . . . . . . . 24
Diesel Particulate Filter
Diesel Particulate Filter . . . . . . . . 24
Diesel Exhaust Fluid
Diesel Exhaust Fluid . . . . . . . . . . . 27
Brakes
Exhaust Brake . . . . . . . . . . . . . . . . . 30
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . . 31
Fuel Additives . . . . . . . . . . . . . . . . . 32
Fuel for Diesel Engines . . . . . . . . 32
Biodiesel . . . . . . . . . . . . . . . . . . . . . . . 33
Cold Weather Operation . . . . . . . 34
Water in Fuel . . . . . . . . . . . . . . . . . . 34
Running Out of Fuel . . . . . . . . . . . 38
Fuel Filter Replacement . . . . . . . 38
Filling the Tank . . . . . . . . . . . . . . . . 40
Filling a Portable Fuel
Container . . . . . . . . . . . . . . . . . . . . . 41
Trailer Towing
Trailer Towing . . . . . . . . . . . . . . . . . . 42
Conversions and Add-Ons
Power Take-Off (PTO) . . . . . . . . . 46
Starting and
Operating
Starting the Diesel
Engine
The diesel engine starts differently
than a gasoline engine.
Caution
If the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
while starting the vehicle, damage
may occur to the hydraulic power
steering system and there may be
loss of power steering assist.
Move the shift lever to P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral) only.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
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Driving and Operating 17
Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped.
Starting the Engine
1. Turn the ignition key to
ON/RUN.
Observe the wait-to-start light.
See Wait-to-Start Light 012.
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
038.
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 069. 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 021.
See Fuel for Diesel Engines 032 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 038.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336155) - 2020 - CRC - 5/6/19
18 Driving and Operating
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 032.
If the engine starts, runs a short
time, then stops, the vehicle needs
service.
{Warning
Do not use gasoline or starting
aids, such as ether, in the air
intake. They could damage the
engine, which may not be
covered by the vehicle warranty.
They could also cause a fire,
which could cause serious
personal injury.
Engine Idle Variations
Under certain conditions the engine
idle speed can vary or be elevated.
Change in idle speed is normal and
does not indicate a problem. Normal
conditions that can raise idle speed
are low voltage, DPF regeneration,
air conditioning compressor loads,
and engine warmup. These speeds
can range from approximately 600
to 1000 rpm.
Elevated Idle
The engine has a cold temperature
high idle feature which elevates the
engine idle speed from base idle to
1050 to 1100 rpm for pickup models
or 1200 rpm for van models when
outside temperatures are below 0 °C
(32 °F), and the engine coolant
temperature is below 65 °C (150 °F).
This feature enhances heater
performance by raising the engine
coolant temperature faster.
To turn this feature on or
off on pickup models,
see Vehicle Personalization (Van
Models) 014 or
Vehicle Personalization (Pickup
Models) 014.
On van models, this feature can be
turned on and off using the DIC
buttons.
When the engine is started, it will
slowly ramp up to the high idle
speed after a delay of a few
seconds up to approximately

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
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Driving and Operating 19
two minutes. For this method to
work properly there must be no
throttle or brake pedal faults.
The engine idle speed will return to
normal once the following conditions
are met:
.Engine coolant temperature
reaches 65 °C (150 °F).
.Air intake temperature reaches
0 °C (32 °F).
The high idle speed will be
temporarily interrupted and the
engine speed will return to normal if
any of the following conditions
occur:
.The brake pedal is applied.
.The accelerator pedal is
pressed.
.The transmission is shifted out
of P (Park) or N (Neutral).
.Vehicle speed is detected.
Once these inputs are removed, the
engine idle speed will slowly ramp
back up to high idle after the normal
delay, if the conditions for engine
coolant temperature and air intake
temperature are still met.
Fast Idle Control (Vans Only)
The vehicle may have this system
which can be used to increase the
engine idle speed.
Fast Idle control will be enabled
when the following conditions
are met:
.The parking brake is set.
.The transmission is in P (Park)
or N (Neutral).
.The vehicle speed is about
0 km/h (0 mph).
.The cruise control Set switch is
pressed and released for Preset
Fast Idle Speed (1200 rpm).
Fast Idle control will be disabled
when one or more of the following
conditions occur:
.The cruise control Set switch is
pressed and released. See
“Cruise Control”in the owner’s
manual.
.The cruise control Cancel switch
is pressed.
.The brake pedal is pressed.
.The transmission is shifted out
of P (Park) or N (Neutral).
.The parking brake is released.
.The vehicle speed is not
0 km/h (0 mph).
On vans, when fast idle is active, a
FAST IDLE ON message will be
displayed in the DIC.
Winter Cover
Pickups
Do not use a winter cover on
pickups.
Vans
If equipped, the winter cover can be
used to enhance heater
performance in extremely cold
conditions below −18 °C (0 °F). The
winter cover installs over the grille
and restricts airflow to the engine
compartment.