2020 CHEVROLET LOW CAB FORWARD check engine

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
162 Driving and Operating
filled before leaving the vehicle
standing for an extended
period.
Do not use starting aids in the air
intake system. Such aids can cause
immediate engine damage. See
Fuel for Diesel Engines 0218.
Stopping the Engine
When stopping the engine, take the
following steps: 1. Bring the vehicle to a complete stop.
2. Firmly apply the parking brake.
3. Move the selector lever to the P position and make sure that
the shift indicator shows P.
4. Allow the engine to idle for approximately 3 minutes.
5. Turn the engine control switch to the ACC or LOCK position.
Do not shut down the engine
immediately after driving the vehicle.
Otherwise, a seizure or other
failures may result. To prevent the battery from going
dead, turn the engine control switch
to the ACC or LOCK position after
stopping the engine. If you leave the
vehicle for an extended period of
time, place the engine control switch
in the LOCK position.
Let the engine idle for 3 minutes
before shutting off the engine. This
allows the turbocharger to slow
down while keeping the bearings
lubricated.
If the Vehicle Has Not Been Used
for a Long Period
If a diesel vehicle has been
standing for an extended period of
time, the turbocharger bearings
should be pre-lubricated prior to
starting. See your authorized dealer
for more detailed information.
Before using a vehicle that has not
been driven for a long period, check
the engine and transmission for oil
leakage, and make sure the oil is at
the required levels. If there is
insufficient oil, it will not adequately
reach and lubricate components,
and a breakdown will result.Start the engine and allow it to idle
for at least five minutes. Check for
abnormal noises.
For instructions on warming up the
engine, refer to
“Starting the Engine”
previously in this section.
If one year has passed since the
diesel exhaust fluid (DEF) in the
DEF tank was added, the DEF in
the tank should be replaced. Be
careful not to inhale the ammonia
odor when replacing the DEF. Also,
please contact your nearest dealer
about the replacement work.
Operating Temperature
Recommendations for Warming
Up the Engine
The engine is sufficiently warmed
up when the needle of the engine
coolant temperature gauge starts
to move.
Do not race the engine or quickly
accelerate before the engine has
sufficiently warmed up. Oil would
not have adequately reached and
lubricated components, and a
breakdown may result.

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
166 Driving and Operating
The cruise set indicator light will
stop flashing and the engine speed
will return to normal.
Engine Checks Before
Operating
Checks Before Operating
Allow the engine to warm up before
placing the engine under heavy load
driving. While the engine is warming
up under light load, the following
checks should be made:1. Observe the red engine oil pressure warning light. The
light should go out when the
engine is running. If it stays on,
shut the engine off and find the
cause.
2. Look at the engine coolant temperature gauge. If the
gauge reaches the H (HOT)
area, stop the engine and find
the cause of the overheating.
3. Check that the battery warning light has gone out. The light
should go off and stay off at
normal idle speeds. If the light does not go out or comes on
during normal operation, have
the charging system checked.
4. Check that the brake low vacuum warning light is out
and that the vacuum buzzer is
not sounding. It is normal for
the warning buzzer to sound
for a few seconds after the
engine starts. If the light and
buzzer remain on, do not drive
the vehicle until the cause has
been found and corrected.
5. Look at the brake system warning light. It should be out
when the parking brake is
released and the engine is
running. If it stays on, it could
mean that the brake fluid level
is low. Check the brake fluid
reservoir. This condition must
be corrected before moving the
vehicle.
{Warning
To reduce the chance of personal
injury and/or vehicle damage due
to engine overheating, never
leave the engine idling without an
alert driver present. If the engine
should overheat, as indicated by
the engine coolant temperature
gauge, immediate action is
required to correct the condition.
Continued operation of the
engine, even for a short time, may
result in a fire.
Do not engage the exhaust brake
while the engine is idling as this
may cause engine overheating.
You and others could be seriously
injured.
Avoid Unnecessary Idling of the
Diesel Engine
If the diesel engine idles too long,
the engine coolant temperature will
fall below the operating range. Low

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
168 Driving and Operating
Warning (Continued)
grass vegetation or stubble
high enough to touch, catch
or collect on its hot exhaust
system.
‐ Parking or idling should be
done only in an area where
there are no combustible
materials under the vehicle.
Failure to follow these
instructions could damage
your vehicle or nearby
property.
Engine Exhaust
Engine Exhaust Emissions
Caution (Carbon Monoxide)
{Warning
Do not breathe exhaust gas
because it contains carbon
monoxide, which by itself has no
color or odor. Carbon monoxide is
a dangerous gas. It can cause
unconsciousness and can be
lethal.
Do not keep the engine running
for any length of time in a place
that is poorly ventilated. It is
particularly dangerous to run the
engine in a garage or other indoor
place that could easily fill with
exhaust gases because you could
suffer carbon monoxide
poisoning.
Inspect the exhaust pipe from
time to time. If you notice any
defect (for example, a damaged
(Continued)
Warning (Continued)
joint, or a hole or crack caused by
corrosion), have checks and
maintenance performed by the
nearest dealer. Continuing to use
the vehicle without having the
defect repaired would be
dangerous because exhaust
gases could get into the cab and
cause carbon monoxide
poisoning.
If at any time you think exhaust
fumes are entering the cab, have
the cause determined and
corrected as soon as possible.
If you must drive under these
conditions, drive only with all
windows fully open. Prevent
carbon monoxide from entering
the cab. The best way is to keep
the engine exhaust system, cab
and cab ventilation system
properly maintained.
(Continued)

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 171
Diesel Particulate
Filter
Diesel Particulate Filter (DPF)
The DPF purifies diesel exhaust
gases of particulate matter (PM). PM
is filtered from the exhaust gas and
collected in the DPF. When PM is
collected to the predetermined level
by the engine control module, the
DPF automatically burns the PM in
a process called regeneration.
Regeneration may not be completed
under certain driving conditions.
If this occurs, the Driver Information
Center (DIC) will provide prompts to
properly complete DPF
regeneration.
The following sections will provide
details on DPF regeneration. Follow
the steps carefully to keep the DPF
in good working order. SeeDriver
Information Center (DIC) 070,
Recommended Fluids and
Lubricants 0339, and Engine Oil
0 235.
{Warning
Exhaust parts and gases become
very hot when the DPF is being
regenerated.
Parking over flammable items
could allow them to touch hot
exhaust parts under your vehicle
and cause them to ignite. Do not
park over papers, leaves, grass
or other things that can burn. You
and others could be seriously
injured.
This content is to restore the
function of the DPF and it is not a
malfunction. However, the check
engine malfunction indicator light
and reduced engine power indicator
light may come on and the power
output may be limited if driving or
power take-off (PTO) operation is
continued for a long time with the
regeneration required warning light
or selectable (switch) regeneration
required warning light (amber/
red) on. This is to prevent the DPF from
being damaged. When operating
PTO during parking, check to
ensure that the regeneration
required warning light or selectable
(switch) regeneration required
warning light (amber/red) on the DIC
is not on.
Engine oil that supports DPF (low
ash oil) is recommended. Use of low
ash oil extends the maintenance
interval of the DPF filter.
Do not modify the DPF or exhaust
pipe. Changing the alignment,
length or diameter of the exhaust
pipe would adversely affect the
exhaust system's exhaust emission
reduction function. If any
modification is necessary to install a
component to the rear of the
vehicle, consult your dealer.
Although the DPF filter automatically
undergoes regeneration (burning of
the accumulated PM) when a
certain amount of PM has
accumulated, driving conditions can
prevent completion of regeneration.

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
174 Driving and Operating
The DPF performs regeneration
automatically when a certain
quantity of PM accumulates in the
filter.
Depending upon running conditions,
however, the regeneration may
sometimes not be completed. In this
case, the regeneration required
warning light (amber) will come on,
so promptly operate the emergency
regeneration according to the
Emergency Regeneration
Procedure. This operation recovers
the function of the DPF. It does not
mean that a breakdown has
occurred.
The engine speed may increase
and the exhaust brake may activate
while the vehicle is stopped with the
engine idling. When this occurs, the
DPF is automatically regenerated.
This does not indicate a failure.
The system generates a sound
during the automatic regeneration
and its cancellation. This does not
indicate a failure.DPF SwitchThe DPF switch is used to burn PM
(regenerate the filter). You can
initiate regeneration when the
regeneration required warning light
or selectable (switch) regeneration
required warning light turns on with
short repeated beeps.
Continuing driving without
performing the regeneration will
cause the check engine malfunction
indicator light and reduced engine
power indicator light to come on.
The DPF then must be repaired at
the nearest dealer.
Emergency Regeneration
Procedure
If the regeneration required warning
light (amber) or selectable (switch)
regeneration required warning light
(amber) turns on the DIC, the DPF
could not satisfactorily complete
automatic regeneration and driver
action is required. If the
regeneration required warning light
(Not selectable (switch)
regeneration warning light) is turned
on, you can choose from Running

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 175
regeneration or Switch regeneration
in order to complete the DPF
regeneration.
If the selectable (switch)
regeneration required warning light
turns on, you have to perform
Switch regeneration in order to
complete the DPF regeneration.
If you continue driving too long with
the regeneration required warning
light (amber) or selectable (switch)
regeneration required warning light
(amber) displayed on the DIC
without performing one of the
possible regenerations, the
message will change to red
Regeneration Required warning
light or selectable (switch)
regeneration required warning light.
The red regeneration required
warning light or selectable (switch)
regeneration required warning light
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 red
regeneration required warning lightor selectable (switch) regeneration
required warning light is displayed
on the DIC.
Continuing to drive 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)
0
70.
Running Regeneration Procedure
Use this option for completing DPF
regeneration, if driving conditions
and traffic allow you to maintain a
relatively constant speed above
48 km/h (30 MPH) for about
20 minutes.
Follow the steps below to use
Running regeneration: 1. Determine if road and traffic conditions allow for relatively
constant speeds above
48 km/h (30 MPH). 2. Increase the vehicle speed
above 48 km/h (30 MPH) and
keep a constant speed.
3. When vehicle speed, engine coolant temperature and other
factors are met the engine
control module (ECM) will
begin DPF regeneration and
the regeneration in progress
indicator light (amber) will
appear on the DIC.
4. Continue driving until the regeneration in progress
indicator light (amber) goes off.
When this indicator light goes
off the DPF regeneration is
complete.
See Driver Information Center (DIC)
0 70.
While the vehicle is at a stop with
engine idling, the engine speed
increases.

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.