GMC Duramax 3.0L Owner's manual

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20_MUL_3.0L_Duramax_Diesel_Engline_Supplement__COV_en_US_84458629B_2019SEP09.ai 1 9/4/2019 8:32:10 AM20_MUL_3.0L_Duramax_Diesel_Engline_Supplement__COV_en_US_84458629B_2019SEP09.ai 1 9/4/2019 8:32:10 AM

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Contents Introduction . . . . . . . . . . . . . . . . . . . . . . 2
Instruments and Controls . . . . . . . . 5
Driving and Operating . . . . . . . . . . 14
Vehicle Care . . . . . . . . . . . . . . . . . . . . 35
Service and Maintenance . . . . . . . 54
Technical Data . . . . . . . . . . . . . . . . . 64
Index ..................... 67

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
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, SILVERADO,
SIERRA, 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. 84458629 B Second Printing ©2019 General Motors LLC. All Rights Reserved.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
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 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
4 Introduction
2NOTES

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Instruments and Controls 5
Instruments and
Controls
Warning Lights, Gauges, and
Indicators
Instrument Cluster . . . . . . . . . . . . . . 6
Malfunction Indicator Lamp
(Check Engine Light) . . . . . . . . . 10
Wait-to-Start Light . . . . . . . . . . . . . . 11
Diesel Exhaust Fluid (DEF)
Warning Light . . . . . . . . . . . . . . . . 12
Information Displays
Driver Information
Center (DIC) . . . . . . . . . . . . . . . . . 12

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
6 Instruments and Controls
Warning Lights, Gauges, and Indicators
Instrument Cluster
Base Level Chevrolet English Cluster, Metric Similar

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Instruments and Controls 7
Base Level GMC English Cluster, Metric Similar

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
8 Instruments and Controls
Uplevel GMC English Cluster, Metric Similar

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Instruments and Controls 9
Uplevel Chevrolet English Cluster, Metric Similar

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
10 Instruments and Controls
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 020.
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
(Continued)
Caution (Continued)
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
035.
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.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Instruments and Controls 11
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.
See Starting the Diesel Engine 014.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
12 Instruments and Controls
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 020.
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:
DEF : Displays the Diesel Exhaust
Fluid (DEF) level as a bar graph
with individual segments that
illuminate from Empty (E) to Full (F).
When LOW appears on the display
and the segments turn red, add
DEF as soon as possible. For a
guide on how much DEF to add,
see Diesel Exhaust Fluid 020.
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.
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 thumbwheel for
two seconds while Fuel Filter Life
Remaining is displayed on the DIC.
Engine Air Filter Life : Displays an
estimate of the engine air filter’s
remaining useful life and the state of
the system. Engine Air Filter Life
95% means 95% of the current air
filter life remains. Messages will
display based on the engine air filter

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Instruments and Controls 13
life and the state of the system.
When the REPLACE AT NEXT OIL
CHANGE message displays, the
engine air filter should be replaced
at the time of the next oil change.
When the REPLACE SOON
message displays, the engine air
filter should be replaced at the
earliest convenience. The Air Filter
Life display must be reset after the
engine air filter replacement. To
reset, see Engine Air Filter Life
System 041.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
14 Driving and Operating
Driving and
Operating
Starting and Operating
Starting the Diesel Engine . . . . . 14
Engine Heater . . . . . . . . . . . . . . . . . 16
Diesel Particulate Filter
Diesel Particulate Filter . . . . . . . . 17
Diesel Exhaust Fluid
Diesel Exhaust Fluid . . . . . . . . . . . 20
Brakes
Exhaust Brake . . . . . . . . . . . . . . . . . 24
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . . 24
Fuel Additives . . . . . . . . . . . . . . . . . 25
Fuel for Diesel Engines . . . . . . . . 25
Biodiesel . . . . . . . . . . . . . . . . . . . . . . . 26
Cold Weather Operation . . . . . . . 27
Water in Fuel . . . . . . . . . . . . . . . . . . 27
Running Out of Fuel . . . . . . . . . . . 30
Fuel Filter Replacement . . . . . . . 31
Filling the Tank . . . . . . . . . . . . . . . . 31
Filling a Portable Fuel
Container . . . . . . . . . . . . . . . . . . . . . 34
Trailer Towing
Trailer Towing . . . . . . . . . . . . . . . . . . 34
Starting and
Operating
Starting the Diesel
Engine
The diesel engine starts differently
than a gasoline engine.
Move the shift lever to P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral) only.
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. Place your foot on the brake
and press ENGINE
START/STOP.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Driving and Operating 15
Observe the wait-to-start light.
See Wait-to-Start Light 011.
This light may not come on if
the engine is warm.
2. The wait-to-start light may be
illuminated, depending on
temperature conditions. There
will be a delay in engine
cranking after pressing
ENGINE START/STOP based
on temperature conditions. In
extremely cold temperatures
the delay will be longer. At the
end of the delay the engine will
begin to crank and will continue
to crank until the engine starts.
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 038. 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 heater. See
“Engine Heater”in the owner’s
manual.
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:
Place your foot on the brake and
press ENGINE START/STOP.
If the wait-to-start 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.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
16 Driving and Operating
If the wait-to-start light comes on
and then goes off and you know the
battery is charged, but the engine
still will not start, the vehicle needs
service.
If the wait-to-start light does not
come on when the engine is cold,
the vehicle needs service.
If the battery does 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 to use 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.
{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.
Engine Heater
{Warning
Do not plug in the engine block
heater while the vehicle is parked
in a garage or under a carport.
Property damage or personal
injury may result. Always park the
vehicle in a clear open area away
from buildings or structures.
If equipped, the engine heater can
provide easier starting in cold
weather conditions at or below
−18 °C (0 °F).
For engine heater operation, see
“Engine Heater”in the owner’s
manual.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Driving and Operating 17
Diesel Particulate
Filter
The exhaust system has a Diesel
Particulate Filter (DPF) to reduce
vehicle emissions. On some
exhaust systems with a DPF, the
exhaust cooler mixes air with the
exhaust to lower the temperature
before it leaves the tailpipe.
The DPF, the tailpipe, and other
exhaust system components must
not be altered. Inspect regularly and
clean any mud or dirt from the
exhaust cooler, especially where the
exhaust cooler connects to the
tailpipe and the openings where
fresh air enters the cooler.
The DPF will clean itself as part of
normal operation. Several factors
including fuel consumed, hours of
engine operation, and miles driven
are monitored by the Engine Control
Module (ECM). The self-cleaning
occurs approximately once per tank
of fuel.
Vehicles with the DPF have
specific fuel and engine oil
requirements. See Fuel for Diesel
Engines 025 and
Engine Oil 038.
Caution
Damage can occur to the DPF
components if the required Ultra
Low Sulfur Diesel (15 ppm sulfur
maximum) fuel and either CJ-4 or
CK-4 engine oil are not used.
This damage would not be
covered by the vehicle warranty.
Under certain conditions, such as
idling or very short trips, the
self-cleaning process has less
efficiency and cannot be completed.
To resolve this, continue driving
safely at a steady speed as close to
the posted speed limit as possible,
preferably without stopping, until the
message turns off. This can take up
to 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 exhaust area clear of
material that could ignite or burn.
See “Parking over Things That
Burn”in the owner’s manual.
Caution
Avoid extended idling because
the DPF system is not capable of
self-cleaning at idle. During
extended idling, monitor the
instrument cluster lights and DIC
(Continued)

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
18 Driving and Operating
Caution (Continued)
for messages and take
appropriate action. Continued
idling with the warning light/
message on could cause damage
to the DPF requiring repair and
possible replacement that might
not be covered by the vehicle
warranty.
During self-cleaning there will be 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 the vehicle is idled or driven on
very short trips with the DPF
warning message on and the
exhaust filter is not cleaned as
required, the malfunction indicator
lamp and a DIC message will
display. See your dealer. Also see
Malfunction Indicator Lamp (Check
Engine Light) 010.
If equipped with Power
Take-Off (PTO), monitor the
instrument cluster for lights related
to the DPF.
See Accessories and Modifications
035 if you are 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 or see
www.gmupfitter.com to contact the
GM Upfitter Integration Group.
If equipped, this feature allows for
manual cleaning/regeneration of the
DPF when it is unable to clean
itself. It may be necessary to
perform manual regeneration if
driving conditions —such as
extended slow speed, stop-and-go
traffic, extended idling, short drive
cycles, or stationary PTO operation
—prevent DPF self-cleaning.
Manual regeneration can only be
used when the DPF has become at
least 90% full. At 100% full, it will
attempt to automatically self-clean if
proper driving conditions are met.
The DPF will clean itself if the
vehicle can be driven for about
30 minutes.
A DIC message displays when
manual regeneration is possible.
Scroll through the DIC pages to find
the Exhaust Cleaning menu.
Depending on whether the vehicle
has a base or uplevel cluster, it may
be under the Settings menu.
If the vehicle cannot be stopped
when the DIC message first
indicates cleaning is available,
automatic self-cleaning may have
begun. If conditions cannot be met
for self-cleaning to complete, and
manual regeneration is selected, it
may take up to four minutes for the
system to switch to manual
regeneration. When the switch
occurs, a DIC message prompts to
start the cleaning process.

Chevrolet/GMC 3.0L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13336148) - 2020 - CRC - 9/5/19
Driving and Operating 19
{Warning
Do not leave the vehicle during
the regeneration.
Make sure that there are no
flammable materials near the
muffler, DPF, and exhaust pipe
which may result in a fire.
The temperature of exhaust
gases is high enough to burn you.
You and others could be seriously
injured.
Before starting manual
regeneration, make sure all of the
following safety conditions are met:
.The vehicle is parked on level
ground, away from any
flammable materials.
.The vehicle is parked outdoors,
away from any walls or
buildings.
.The vehicle is at least 3 m (10 ft)
from any obstructions or
materials that may combust
or melt.
.The shift lever is in P (Park).
.The fuel tank is at least
one-eighth full.
.All fluids are at the proper level.
.No diagnostic trouble codes
have been set, and the
malfunction indicator lamp is
not on.
.The engine coolant temperature
is above 71 °C (160 °F).
After making sure all safety
conditions have been met, press the
trip odometer reset stem or
thumbwheel on the steering wheel
for at least one second to select
Start on the infotainment display.
Follow the instructions in the DIC
messages. Touch ACCEPT to
acknowledge that all of these safety
conditions have been met and to
activate regeneration.
If the infotainment display returns to
the previous screen, then one or
more of the necessary safety
conditions has not been met. If you
cannot determine which condition
has not been met, see
www.gmupfitter.com to contact the
GM Upfitter Integration Group.
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.