Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Driving and Operating 13
Driving and Operating
Starting and Operating
Starting the Diesel Engine . . . . . . . . . . . . . . 13
Winter Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Engine Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Fuel Operated Heater (FOH) (VanModels Only) . . . . . . . . . . . . . . . . . . . . . . . . . 19
Parking over Things That Burn . . . . . . . . . . 19
Diesel Particulate Filter
Diesel Particulate Filter . . . . . . . . . . . . . . . . . 19
Diesel Exhaust Fluid
Diesel Exhaust Fluid . . . . . . . . . . . . . . . . . . . . 22
Brakes
Exhaust Brake . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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 . . . . . . . . . . . . . . . . . 30
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . 32
Filling a Portable Fuel Container . . . . . . . . 34
Trailer Towing
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Conversions and Add-Ons
Power Take-Off (PTO) . . . . . . . . . . . . . . . . . . . 37
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 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.
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.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Driving and Operating 15
{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) 011 or
Vehicle Personalization (Pickup Models) 011.
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
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.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
16 Driving and Operating
.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.
For vehicles that did not come with a winter
cover, a GM winter cover can be purchased.
See your dealer for additional information.
When the winter cover is in use, the heater,
ventilation, and air conditioning AUTO mode
may not function properly. Use the manual
settings for comfort.
Usage Guidelines
The winter cover should only be used while
operating the vehicle in extremely cold
temperatures or in heavy snow for extended
periods. In these temperatures, the vehicle
does not need a large amount of air to
properly cool the engine. When more
airflow is required to cool the vehicle, the
winter cover should not be used. The
following usage guidelines will allow
adequate airflow for proper radiator and air
cooler performance:
.Do not use the winter cover if towing a
trailer. The vehicle may overheat if the
radiator is covered while towing.
.Do not modify the cover. The winter
cover does not cover some sections of the
front of the vehicle to provide enough
airflow.
.When the winter cover is used, the
outside air temperature display may not
function properly.
.Keep the underside of the winter cover as
clean as possible. Remove monthly or as
necessary and clean away dust and
debris.
.Use only a mild soap to clean. Do not use
harsh soap, strong detergents, or vinyl
protectant/sealant type products as they
may damage the special finish. Allow the
winter cover to dry completely before
reinstalling.
Installation Instructions
When first trying to fit the cover, it may
appear to be undersized but will stretch
during installation to ensure a tight fit. The
initial installation of the cover is best
performed when the winter cover is warm.
1. Open the hood and secure it with the prop rod.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Driving and Operating 29
Caution (Continued)
refuel, water was pumped into the fuel
tank. Turn off the engine and drain the
water immediately.
Removing Water from the Fuel Filter
To drain water:1. Turn the engine off and apply the parking brake.
Van
Pickup
2. Place a container under the filter drain valve. The filter drain valve is on the
bottom of the fuel filter. The filter drain
valve is under the vehicle on the driver
side, inside the frame rail.
3. For van models, open the drain valve by turning it counterclockwise. Allow the
filter to drain until all of the water has
been removed. Close the valve.
For pickup models, open the fuel filter
cap by turning it two to three turns.
Allow the filter to drain until all of the
water has been removed. Close the cap
hand tight. 4. Properly dispose of the water
contaminated fuel.
5. Start the engine and let it run for a few minutes. During the draining process, air
may have entered the fuel system. If the
engine stalls, the fuel system may need
to be primed. See “Fuel Priming”
following.
Fuel Priming
For the fuel system to work properly, the
fuel lines must be full of fuel. If air gets in,
the fuel lines need to be primed before
operating the vehicle and the Fuel Operated
Heater (FOH).
If air is present, the following may have
happened:
.The vehicle ran out of fuel.
.The fuel filter was removed.
.The fuel lines were removed or
disconnected.
.The fuel filter water drain valve was
opened while the engine was running.
.The FOH pump and FOH fuel lines were
removed or disconnected.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
30 Driving and Operating
The system is not harmed by air in the fuel
lines; however, the engine and/or the FOH
may not start until the fuel system is
primed and the air is removed.
Priming the Fuel System
There is an electric priming pump that will
bring fuel to the engine and eliminate air in
the fuel lines. To prime the engine:1. Correct any condition that caused the loss of prime.
2. Turn the ignition on for 30 seconds. Do not start the engine. The fuel pump will
start priming.
3. Turn the ignition off, then back to start, and crank the engine for 15 seconds.
4. If the engine does not start, repeat Steps 2 and 3 until the engine starts.
If the engine does not start after
repeating Steps 2 and 3 three times, turn
the ignition key off for 60 seconds.
5. Repeat the above steps until the engine starts.
6. If the engine starts, but does not run smoothly, increase the engine speed
slightly. 7. If the engine starts and runs but stalls
again, turn the ignition off for
60 seconds.
8. When the engine starts, let it idle for a few minutes and check the filter for any
leaks.
To Prime the Fuel Operated Heater (FOH)
Fuel Lines (Van Models)
See your dealer or qualified technician if the
FOH fuel lines need to be primed.
Running Out of Fuel
If the engine has stalled due to running out
of fuel, try to restart it: 1. If parked on a level surface, add at least 3.8 L (1 gal) of fuel. Up to 18.9 L (5 gal)
may be needed if parked on a slope.
2. Follow the vehicle fuel system priming procedure earlier in this section to
re-prime the system and restart the
engine.
If the check engine light comes on due to
running out of fuel, it may take a few drive
cycles to clear.
On van models only, the Fuel Operated
Heater (FOH) stops automatically when the
fuel tank volume is less than or equal to 10% of the total tank. The FOH fuel lines
will not need to be primed if the vehicle
runs out of fuel.
Fuel Filter Replacement
Van Models
{Warning
Diesel fuel is flammable. It could start a
fire if something ignites it, and people
could be burned. Do not let it get on hot
engine parts, and keep matches or other
ignition sources away.
The fuel filter is on the driver side, inside
the frame rail.
To replace the fuel filter: 1. Drain any water from the filter. See “Removing Water from the Fuel Filter” in
Water in Fuel 027.
Keep the engine off until the procedure
is completed.
2. Apply the parking brake.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Driving and Operating 31
3. Remove the filter element cap by turningit counterclockwise.
4. Remove the filter element. If there is any dirt on the filter sealing surface, clean
it off.
5. Install the new filter element and o-ring.
6. Reinstall and tighten the filter cap to the housing.
7. Use the fuel filter priming procedure to prime the fuel filter. See “Fuel Priming”
in Water in Fuel 027.
8. Start the engine and let it idle for five minutes. Check the fuel filter and air
bleed valve for leaks.
9. Reset the fuel filter monitor. See Driver
Information Center (DIC) 010. If the van Fuel Operated Heater (FOH) (if
equipped) is not working, the FOH line
requires priming. See your dealer for service.
See
Fuel Operated Heater (FOH) (Van Models
Only) 019.
Pickup Models
{Warning
Diesel fuel is flammable. It could start a
fire if something ignites it, and people
could be burned. Do not let it get on hot
engine parts, and keep matches or other
ignition sources away.
The fuel filter is on the driver side, inside
the frame rail in front of the fuel tank. 1. Drain any water from the filter. See
“Removing Water from the Fuel Filter” in
Water in Fuel 027.
Keep the engine off until the procedure
is completed.
2. Apply the parking brake.
3. There are two caps under the filter. Clean the fuel filter area before removing
these two filter caps.
Caution
Failure to cover the fuel filter with a
clean cloth to keep out debris when
replacing may cause dirt to get into the
engine. This could cause engine damage.
Keep the fuel filter covered with a clean
cloth when replacing.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
34 Driving and Operating
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.
.Bring the fill nozzle in contact with
the inside of the fill opening before
operating the nozzle. Maintain contact
until filling is complete.(Continued)
Warning (Continued)
.Keep sparks, flames, and smoking
materials away from fuel.
.Avoid using electronic devices while
pumping fuel.
Trailer Towing
When towing at high elevation on steep
uphill grades, consider the following:
Engine coolant at higher elevation will boil
at a lower temperature than at or near sea
level. If the engine is turned off immediately
after towing at high elevation on steep
uphill grades, the vehicle may show signs
similar to engine overheating. To avoid this,
let the engine run while parked (preferably
on level ground) with the transmission in
P (Park) and the parking brake applied for at
least five minutes before turning the engine
off. If the overheat warning comes on, see
Engine Overheating062. Use the following chart to determine the
maximum the trailer can weigh, based upon
your vehicle model and options.
All axles of the trailer must be equipped
with brakes adequate for the intended use.
Trailer braking equipment conforming to
Canadian Standards Association (CSA)
requirement CAN3-D313, or its equivalent, is
recommended.
Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
38 Driving and Operating
{Warning
Engine exhaust contains Carbon
Monoxide (CO), which cannot be seen or
smelled. Exposure to CO can cause
unconsciousness or even death. Never
operate PTO in an enclosed area such as
a garage or building that has no fresh air
ventilation. See“Engine Exhaust” in the
owner’s manual.
Caution
If the key is in the ignition during
Remote PTO operation, the vehicle can be
shifted out of P (Park). Even though PTO
will be disengaged, depending on PTO
Upfitter application, personal injury or
property damage may result from vehicle
movement. Always remove the key from
the ignition before operating
Remote PTO.
Primary PTO Operating Modes
PTO modes of operation are:
.Preset
Stationary operation only: In-cab control
is standard, remote control is available.
.Variable
Stationary operation only: In-cab control
is standard, remote control is available.
.Mobile
In-cab control only.
.Operator Selectable In-Cab Mode (OSIM)
OSIM is for in-cab operation only.
OSIM is for vehicles that require both
stationary and mobile modes. OSIM is
available via the GM Service Tool only.
During the configuration of OSIM, two
modes must be paired. The options for
pairing are: stationary preset and mobile,
or stationary variable and mobile. During
activation of OSIM, the operator must
select one of the two modes within the
pre-configured pairing. If an OSIM mode is
not selected, PTO will not operate.
OSIM modes of operation are:
‐ Stationary
For stationary mode, the configuration
may be stationary preset or stationary
variable.
‐ Mobile
For mobile mode, the configuration is
variable only. Selection between OSIM pairings is not
available.
Remote modes are not available.
The factory default programming enables
in-cab control. For stationary modes, a GM
Service Tool can reprogram the system to
allow for remote control and disable the
in-cab control.
All PTO modes provide for engine rpm
control and PTO load relay control.
All PTO modes provide for safety interlocks
for PTO load disengagement.
Remote PTO modes provide for remote
engine starting and shutdown.
Stationary in-cab and Remote PTO modes
provide for engine shutdown due to critical
engine conditions, as well as a timed engine
shutdown feature.
Preset PTO
Preset Enable Conditions –In-Cab Operation
To enable PTO: 1. With the engine running, shift the vehicle into P (Park) and set the parking
brake. Do not press the brake pedal.
2. Confirm that cruise control is off.