2020 CHEVROLET LOW CAB FORWARD warning

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 177
displayed on the DIC, the message
will change to red. The selectable
(switch) regeneration required
warning light (red) indicates the
DPF filter is nearly full of PM, a
condition which may be damaging
to the filter.
DPF regeneration should be
completed immediately if the
selectable (switch) regeneration
required warning light (red) is
displayed on the DIC.
Continued driving without
performing DPF regeneration will
cause the check engine malfunction
indicator light and reduced engine
power indicator light to come on, an
engine power reduction, and may
cause damage to the DPF filter. See
Driver Information Center (DIC)
070.
When operating the PTO for a long
time if your vehicle is so equipped,
make sure that the regeneration
required warning light or selectable
(switch) regeneration required
warning light (amber) is not
turning on. Once the Switch regeneration is
started, it cannot be switched to the
Running regeneration if interrupted.
When the Switch regeneration is
selected, end regeneration in a
single operation if possible.
During the regeneration, the engine
speed may vary, causing the
exhaust brake valve to be
deactivated. However, while the
regeneration in progress indicator
light (amber) appears, regeneration
is still taking place, so continue to
perform regeneration until the
message goes off.
The time needed to complete
regeneration differs depending on
the outside temperature.
The exhaust brake or exhaust
throttle is activated during DPF
regeneration. The exhaust brake or
exhaust throttle starting to operate
or being disengaged will produce a
sound, but this does not indicate a
failure.
During regeneration, white smoke
may be temporarily produced from
the exhaust pipe. This results from
combustion of PM, it does not
indicate a failure.
Switch regeneration will complete
earlier immediately after driving than
when the engine is cold.
The engine coolant temperature
may rise during switch regeneration.
Interruption of Switch
Regeneration
If you must interrupt regeneration for
an unavoidable reason, press the
DPF switch again.
The regeneration in progress
indicator light (amber) changes to
the selectable (switch) regeneration
required warning light (amber).
Then, you can drive the vehicle.
If you interrupt regeneration, you
need to perform regeneration again.
Perform switch regeneration
beginning with Step 1 as soon as
possible.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
178 Driving and Operating
Switch regeneration will be
interrupted in the following
circumstances:
.Accelerator pedal is pressed.
. Gear-in.
. Vehicle speed is above
0 km/h (0 MPH).
. Engine speed increases.
Operation noise caused by
interruption is louder when pressing
the accelerator pedal than other
operations. This is not a failure.
Selectable Regeneration
Procedure
Your vehicle is equipped with
Selectable Regeneration. This
procedure is designed for vehicles
that do not normally operate in
conditions that make automatic
regeneration possible. This function
allows the driver to check the status
of the PM level and, when available,
perform Switch regeneration at a
convenient time for the driver. Selectable regeneration may only
be performed when no other DPF
message is present on the DIC. Be
sure to follow any DPF messages
present on the DIC to properly
complete a DPF regeneration.
It is recommended to use the
procedure during breaks in PTO
operation (if equipped) and other
low speed applications.
{Warning
Do not leave the vehicle during
the regeneration.
Make sure that there are no
flammables near the muffler, DPF
and exhaust pipe which may
result in a fire.
Remember that the temperature
of exhaust gases is high enough
to burn you. You and others could
be seriously injured.
1. Stop the vehicle at a safe place
free of flammable material such
as dead grass, leaves or waste
paper.
2. Move the selector lever into the P position and firmly engage
the parking brake.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 179
3. Run the engine at idle. Be surethe accelerator pedal is not
pressed and the PTO switch (if
equipped) is OFF.
4. Press and hold the DPF switch until the amber checking PM
Level indicator light appears on
the DIC.
5. If Selectable regeneration is available, the selectable
(switch) regeneration required
warning light (amber) will
appear on the DIC. If this
indicator light does not appear
on the DIC, the PM level in the DPF filter is OK and DPF
regeneration is not needed at
this time.
6. Press and release the DPF switch to begin regeneration.
7. The selectable (switch) regeneration required warning
light (amber) will change to
regeneration in progress
indicator light.
8. Do not leave the vehicle during the regeneration. Regeneration
normally completes in about
20 minutes, if the engine is at operating temperature.
Regeneration may take longer
if the engine is cold.
9. When the regeneration in progress indicator light goes
out, the Selectable
regeneration is complete.
If the Selectable regeneration is
interrupted, a selectable (switch)
regeneration required warning light
(amber) will appear on the DIC. You
must complete the DPF
regeneration by performing the
Switch regeneration as soon as
possible when Selectable
regeneration is interrupted.
If you continue driving too long with
the selectable (switch) regeneration
required warning light (amber)
displayed on the DIC, the warning
light will change to red. The
selectable (switch) regeneration
required warning light (red) indicates
the DPF filter is nearly full of PM, a
condition which may be damaging
to the filter. DPF regeneration
should be completed immediately if

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
180 Driving and Operating
the selectable (switch) regeneration
required warning light (red) is
displayed on the DIC.
Continued driving without
performing DPF regeneration will
cause the check engine malfunction
indicator light and reduced engine
power indicator light to come on, an
engine power reduction, and may
cause damage to the DPF filter. See
Vehicle Messages074.
The time needed to complete
regeneration differs depending on
the outside temperature.
The exhaust brake is activated
during DPF regeneration. The
exhaust brake starting to operate or
being disengaged will produce a
sound, but this does not indicate a
failure.
During regeneration, white smoke
may be temporarily produced from
the exhaust pipe. This results from
combustion of PM, it does not
indicate a failure.
Regeneration is finished earlier
immediately after driving than when
the engine is cold. The engine coolant temperature
may rise during regeneration.
DPF Regeneration during
Prolonged Idling
DPF regeneration may be initiated
automatically during prolonged
idling. If regeneration is initiated, the
regeneration in progress indicator
light (amber) comes on but this is
normal and does not indicate a
failure.
If driving is started or the PTO is
connected during DPF regeneration
by prolonged idling, the selectable
(switch) regeneration required
warning light (amber) comes on and
regeneration is suspended. Perform
Switch regeneration procedure in
order to complete the DPF
regeneration.
Prolonged idling may require more
frequent DPF regeneration.
See
Driver Information Center (DIC)
0 70.Diesel Exhaust Fluid
Diesel exhaust fluid (DEF) is used
exclusively for the selective catalytic
reduction (SCR) system. Be sure to
use only API certified DEF. When
the SCR system detects DEF level
is nearly empty or incorrect fluids
(such as water or low concentrated
DEF.) are added, the SCR system
will turn on warning and indicator
lights and reduce engine power in
progressive stages to encourage
you to have the condition corrected.
Continuing to drive for too long after
these lights come on will eventually
result in a severe vehicle speed
limitation. See Vehicle Messages
0 74
The DEF freezes below −11 °C
(12 °F). The SCR system is
equipped with a heating function
which utilizes the engine coolant, so
the engine can be started even
when DEF is frozen.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 181
Handling of DEF
Use only API certified DEF (or ISO:
AUS 32). DEF is a colorless,
transparent solution. It may smell
depending on the conditions, but
this is not abnormal.
DEF is available from your local
authorized dealer. In addition, the
U.S. Department of Energy has
created an on-line DEF locator that
can be accessed at http://
www.afdc.energy.gov/afdc/locator/
def/. The American Petroleum
Institute (API) also maintains a list
of API-certified distributors of DEF
on its web page at http://
www.apidef.org/searchresults.asp.
{Warning
Though DEF should be harmless
for physical contact, in the rare
case in which it induces make
sure to take following actions:
In the event that DEF does come
into contact with your skin, wash
it off with water and/or soap.(Continued)
Warning (Continued)
Although it is rare, a person with
sensitive skin may suffer from
irritation. If you come into contact
with DEF, flush the affected area
with water and/or soap. If irritation
or redness develops or persists,
seek medical attention.
If it is accidentally swallowed,
drink 1-2 glasses of water or milk
and seek immediate medical
attention.
If it does come into contact with
an eye, immediately rinse it off
with a large amount of water for
at least 15 minutes, and then
seek medical attention.
You and others could be seriously
injured.
See Winter Driving 0142, and
Recommended Fluids and
Lubricants 0339. Adding DEF Before Driving the
Vehicle
Add DEF regularly to maintain an
adequate supply. If the DEF level
becomes too low the DEF low level
warning system may activate. The
vehicle speed will be severely
limited when the DEF tank is empty.
Be sure to obey the following
instructions when refilling the
vehicle:
.
Stop the engine before
adding DEF.
. When filling, place the nozzle
deeply into the DEF tank. If you
try to fill more DEF by pulling out
the nozzle from the DEF tank,
DEF may spill out.
. Obey all cautions posted in filling
stations.
. When DEF is spilled, wash it
away with water and wipe the
area clean.
. Add API certified DEF only (or
ISO: AUS 32). Do not fill the
DEF tank with any substance
other than the DEF.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 183
{Warning
On occasion, you may notice an
odor when the DEF tank is
opened. Do not sniff the filler
port, etc.
When refilling the DEF tank:
Failure to follow the above
instructions could result in a fire
or a breakdown of the selective
catalytic reduction (SCR) system.
Do not dilute DEF with water.
Do not add substances such as
gasoline or diesel fuel to the DEF
tank. You and others could be
seriously injured.
Caution
When opening the DEF tank cap,
be careful not to let dirt or other
foreign matter enter inside the
DEF tank. Intrusion of foreign
matter can cause a clogging of(Continued)
Caution (Continued)
the filter or affect the quality of
DEF, which may result in a SCR
system failure.
If DEF is spilled on the body or
frame, it may cause generation of
rust, so wipe it off and then rinse
it away with water.
When DEF dries it will leave a
crystalline residue, this condition is
normal. Wash with water or wipe
away the residue to prevent it from
entering the DEF tank.
Adding DEF in Cold Weather
DEF freezes at low temperature but
the engine coolant circulates to
thaw the DEF tank and to prevent
DEF from freezing. Vehicle can be
driven normally when DEF is frozen.
If the refill diesel exhaust fluid (DEF)
warning light is on and the
remaining DEF in the DEF tank is
frozen, the warning lights, indicator lights and restriction will not be
canceled until the DEF thaws even
if the DEF tank is refilled.
It is not recommended parking the
vehicle for long periods with the refill
diesel exhaust fluid (DEF) warning
light on in cold weather. The DEF
gauge will not register correctly
should the DEF freeze in this
condition causing the DEF low level
warning system not to reset when
DEF is added. Take the following
actions to avoid this condition in
cold weather:
1. Refill the DEF as soon as possible after parking the
vehicle.
2. Turn the engine control switch to the ON position from the
LOCK position.
3. Wait for the warning buzzers and warning lights to turn off.
4. If the buzzer does not stop, return the engine control switch
back to the LOCK position and
add more DEF, and then start
over from step (2) above.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
184 Driving and Operating
5. Turn the engine control switchto the LOCK position.
The DEF freezes at approximately
−11 °C (12 °F).
In cold weather, when the vehicle is
left without performing these actions
and the DEF tank freezes, the low
DEF level warnings and indicators
may not turn off when DEF is added
until after the tank defrosts.
Make sure to stop the engine before
adding the DEF. See Warning
Buzzers 079.
When DEF Freezes
Engine coolant circulates through
the DEF tank to thaw it when frozen
and prevent it from freezing while
the engine is running. The vehicle
can be driven normally when DEF is
frozen in the DEF tank.
If the Refill DEF warning light is on
and the remaining DEF in the DEF
tank is frozen, the vehicle low level
warning system cannot be reset by
adding DEF. The DEF gauge will not
register correctly should the
remaining DEF freeze at this level. Move the vehicle to a location to
allow the DEF to thaw. Once the
DEF is thawed the DEF gauge
should read correctly allowing the
low level warning system to reset.
To avoid this condition follow the
instructions for Adding DEF in Cold
Weather.
{Warning
Do not warm up the DEF tank
using a burner, heater, etc. You
and others could be seriously
injured.
DEF Storage
Seal the container and store it in an
indoor place with good ventilation
avoiding direct sunlight.
When storing DEF, the shelf life
varies depending on the room
temperature of the storage place.
For details, please contact the
distributor of the DEF. For storage of DEF, seal the
container to prevent the moisture
from evaporating.
Even when DEF has been frozen,
its quality is maintained when it is
thawed. It can be used as it is.
To store or carry DEF, use the
original container in which the DEF
was kept at the time of purchase.
Also, if other containers are used,
prepare a clean container for
exclusive use, which can be a
polyethylene resin tank (PE) or
stainless steel container, and do not
introduce foreign matter such as
water or contamination.
DEF Disposal
Do not dispose of DEF and the
empty container into lakes, marine
areas, rivers, etc. DEF must be
disposed of in a method conforming
to the regulatory requirements in
your state.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 185
Selective Catalytic Reduction
(SCR) System
The Selective Catalytic Reduction
(SCR) system reduces nitrogen
oxide (NOx) emissions emitted from
a diesel engine. The SCR system
reduces NOx by adding (injecting)
Diesel Exhaust Fluid (DEF) into the
exhaust system and inducing a
reaction converting NOx into water
vapor and nitrogen.
The SCR system consists of the
DEF tank, DEF Control Unit, DEF
Supply Pump and Injector, and the
SCR Catalyst. It is important to keep
a good supply of DEF in the DEF
tank at all times. Monitor the DEF
gauge to be sure the DEF tank level
does not become too low.
If the DEF level becomes too low or
incorrect fluid is added to the DEF
tank, the warning buzzer will sound,
warning and indicator lights will
come on and engine power will be
reduced. If you see these warning
and indicator lights, add DEF as
soon as possible or have your
vehicle serviced as soon as
possible.Continuing to drive for too long after
these lights come on will result in
additional warnings, more engine
power reduction and will eventually
result in a severe vehicle speed
limitation. See
“Diesel Exhaust
Fluid (DEF) Low Level Warning” and
“Incorrect Diesel Exhaust Fluid
(DEF)/SCR System Malfunction
Warnings” later in this section.
{Warning
Do not touch the water that
comes out from the muffler. The
water is mildly acidified due to the
action of oxidation catalyst inside
the muffler. In the event that the
fluid does come into contact with
your skin, completely wash it off
with water. You and others could
be seriously injured. Do not relocate or modify the
exhaust pipe, muffler, DPF, SCR,
or DEF tank, which may affect the
exhaust gas cleaning performance.
If any relocation or modification is
necessary, consult your dealer.
The SCR system continues to
operate for approximately 3 minutes
after the engine control switch is
turned to the "LOCK" position. It is
normal to hear a buzzing type noise
from the DEF supply pump
(mounted on the left side frame rail
behind the cab) during the
shutdown process.
If it is necessary to disconnect the
batteries for any reason, be sure to
wait at least 3 minutes after turning
the engine control switch to the
"LOCK" position. This will allow the
SCR system to properly complete
its shutdown processes. See
Winter
Driving 0142.