display CHEVROLET LOW CAB FORWARD 2019 Service Manual

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 181
The selectable (switch) regeneration
required warning light (amber) will
turn on when regeneration cannot
be completed automatically. Perform
Running or Switch regeneration in
accordance with the proper
procedure. This is to restore DPF
function and is normal.
The exhaust pipe mixes air with the
exhaust gas to lower its temperature
before it leaves the exhaust pipe.
The frequency of regeneration
increases especially under the
following environments:
‐Midwinter.
‐ Continuous low-speed driving for
long hours (The frequency of
regeneration increases
particularly with special
equipment vehicles such as
sweeper vehicles which mainly
travel at low speed. The
frequency of regeneration is
higher as compared to delivery
vehicles which mainly travel at
standard high speed). Automatic regeneration is performed
under normal driving conditions
(DPF soot accumulation status level
5, and in rare cases, may be
performed at continuously
low-speeds for long hours, except
PM level 5); however, the
regeneration required warning light
(amber) may be displayed in the
DIC under the following driving
conditions:
‐
When only low-speed driving at/
under vehicle speed of 15 km/h
(9 MPH) is performed.
‐ When frequent engine start and
stop are performed.
‐ When the engine stops every
time before the engine is
warmed up.
‐ When continuous idling (over
1 hour) is frequently performed.
If the vehicle is stationary with the
engine idling during DPF
regeneration, the exhaust brake or
exhaust throttle operates. Operating
sounds will be heard when the exhaust brake or exhaust throttle is
activated or deactivated. The
sounds do not indicate a fault.
White smoke could be emitted
briefly from the exhaust pipe in the
following situations, but it is not
indicating a fault.
‐
Combustion of PM during DPF
regeneration.
‐ During DPF regeneration of a
new vehicle which has been
driven a certain distance. The
vehicle may not emit white
smoke during its initial operation
when new.
‐ Long continuous idling.
The exhaust brake may
automatically be activated in order
to prevent emission of white smoke
if the engine idles continuously over
an extended period of time.
White smoke may be produced
during switch regeneration; do not
perform switch regeneration in any
poorly ventilated indoor place.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
182 Driving and Operating
White smoke may be produced
during DPF regeneration when a
new vehicle has been driven a
certain distance, but this is not a
malfunction. The vehicle may not
emit white smoke immediately after
purchase.
DPF PM Accumulation Level
This green display only indicates
DPF soot accumulation status. The
DIC can display the PM
accumulation level in green. The L
indicates Low accumulation of PM
and the H indicates High
accumulation of PM in the DPF.
As PM accumulation increases
inside the DPF, the DIC will display
additional bars increasing from L to
H to show the approximate level of
PM accumulation. SeeDriver
Information Center (DIC) 082. DPF Regeneration Status
This amber display indicates the
DPF is regenerating. During DPF
regeneration, the DIC can display
the status of PM reduction in amber.
The highest accumulation level bar
will be flashing as indication of the
regeneration process.
As PM levels decrease in the DPF
during the regeneration process, the
DIC will decrease the number of
bars from H to L. See
Driver
Information Center (DIC) 082.
Automatic Regeneration of DPF
The DPF will regenerate itself as
part of normal operation.
The engine control module (ECM)
controls this function based on
several factors including hours of
operation and mileage. When
automatic regeneration starts, the
regeneration in progress indicator
light (amber) is displayed on
the DIC.
During regeneration the engine idle
speed will increase and the exhaust
brake may activate when the vehicle
is idling while stopped or parked.
Regeneration is normally completed
in about 20 minutes. See Driver
Information Center (DIC) 082.
{Warning
To prevent fire, ensure that there
is no combustible material near
the muffler, the DPF or the
exhaust pipe. Also, be careful not
to burn yourself on the hot
exhaust gas. You and others
could be seriously injured.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
184 Driving and Operating
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
82.
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 82.
While the vehicle is at a stop with
engine idling, the engine speed
increases.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 185
Switch Regeneration Procedure
{Warning
To prevent a fire, make sure that
there is no flammable material
near the muffler, DPF and(Continued)
Warning (Continued)
exhaust pipe. Remember that the
temperature of exhaust gases is
high enough to burn you. You and
others could be seriously injured.
Select Switch regeneration
procedure if the Running
regeneration procedure is not
possible, or if the selectable (switch)
regeneration required warning light
(amber or red) is displayed on
the DIC. 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.
3. Let the engine idle. Be sure the accelerator pedal is not
pressed and the PTO switch (if
equipped) is OFF.
4. Press and release the DPF switch. 5. The regeneration required
warning light (amber or red) or
selectable (switch)
regeneration required warning
light (amber or red) on the DIC
will turn off and the
regeneration in progress
indicator light will appear.
6. Do not leave the vehicle during the regeneration. Regeneration
normally completes in about
20 minutes.
7. When the regeneration in progress indicator light (amber)
goes out, regeneration is
completed. Normal driving is
then possible.
If the Switch 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 once again as
soon as possible.
If you continue driving too long with
the selectable (switch) regeneration
required warning light (amber)

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
186 Driving and Operating
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)
082.
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 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
188 Driving and Operating
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 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 189
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 Messages086.
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 82.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 86
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 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
196 Driving and Operating
DEF Tank Level is Low/Empty
StageStage 1 Stage 2Stage 3Stage 4
DIC main display
DEF gauge (DIC sub
display 2)
Solid (amber)Blinking (amber)Solid (red)Solid (red)

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
200 Driving and Operating
Incorrect DEF/SCR System Malfunction (Type A) Warnings
Stage Stage 1Stage 2Stage 3Stage 4
DIC main display
DEF gauge (DIC sub
display 2) Various Various Various Various
Indicator light(s)
Slow blinkingFast blinkingFast blinking

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 203
SCR System Malfunction (Type B) Warning
StageStage 1
Trigger SCR system malfunction detected
DIC main display
DEF gauge (DIC sub
display 2) Various