lights CHEVROLET LOW CAB FORWARD 2020 Owner's Guide

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
150 Driving and Operating
SymptomCauseCorrective Action Reference
Engine is overheating No engine coolant Add engine coolant
See
Engine
Coolant 0243
Front of radiator is
clogged with dirt Wash clean with tap
waterSee
Exterior Care
0 307
Radiator cap not
sufficiently tightened Make sure it is firmly
tightened or replace the
radiator cap
-
Fan belt loose Adjust the tension or
replace the beltSee
Engine Drive
Belt Routing 0355
Engine coolant dirty
4-
Fan clutch is faulty
4-
Radiator cap dirty or
faulty Clean or replace -
Oil pressure is low Improper engine oil
viscosity
Change to an oil with
proper viscositySee
Engine Oil
0 235
Engine oil level too low Add engine oil See
Engine Oil
0 235
Engine inner
components are faulty
4-
Meter, indicator/warning
lights or switches faulty
4-

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 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
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.

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
186 Driving and Operating
Diesel Exhaust Fluid (DEF) Low
Level Warning
Diesel Exhaust Fluid (DEF) is a
required fluid for the operation of
your diesel engine just as diesel fuel
is required. To avoid running out of
DEF your vehicle will turn on
warning and indicator lights and
reduce engine power in progressive
stages to encourage adding DEF.
The following is a summary of the
diesel exhaust fluid (DEF) low level
warning lights, indicator lights and
engine power reductions.
Continuing to drive for too long after
these lights come on will eventually
result in a severe vehicle speed
limitation.These warning and indicator lights
will go out automatically and engine
power will be restored to normal
after the SCR system detects that
the DEF tank is refilled with 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 189
DEF Tank Level is Low/Empty (cont'd)
StageStage 1 Stage 2Stage 3Stage 4
CAUTION
This message indicates incorrect DEF or an SCR system malfunction. Immediately contact
your dealer to have your vehicle serviced *2
Remarks:
*1 –See Diesel Exhaust
Fluid (DEF).
*2 –See Incorrect Diesel Exhaust
Fluid (DEF) /SCR System
Malfunction Warnings.
*3 –The warning buzzer continues
to sound every 5 minutes.
*4 –The warning buzzer continues
to sound every 5 minutes and when
driving 8 km (5 miles) or more, the
buzzer changes its sound to
continuous beeping. DEF tank low stages are as follows:
Stage 1 :
When the remaining level
of DEF becomes excessively low
the DEF gauge will change color
from green to amber. In addition,
warning and indicator lights will
come on as shown in the table and
engine power will be reduced so the
vehicle speed will not exceed
89 km/h (55 MPH).
Stage 2 : If driving is continued
without adding DEF (approximately
320 km (200 miles)) the DEF gauge,
warning and indicator lights will begin blinking. Again, engine power
will be reduced so the vehicle speed
will not exceed 56 km/h (35 MPH).
Stage 3 :
If driving is continued until
the DEF tank is empty, the DEF
gauge will change color from amber
to red and the warning and indicator
lights will begin to blink faster.
Engine power will still be reduced so
the vehicle speed will not exceed
56 km/h (35 MPH). The vehicle
speed will be limited to
8 km/h (5 MPH) either when the
vehicle is stopped after driving

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
190 Driving and Operating
further on (approximately
8 km (5 miles)) or when the engine
is restarted.
Stage 4 :The DEF gauge is red,
the indicator light is blinking and the
buzzer is beeping continuously
indicates the vehicle speed is
limited to 8 km/h (5 MPH). See
Driver Information Center (DIC)
0 70.
Incorrect Diesel Exhaust Fluid
(DEF)/SCR System Malfunction
Warnings
The SCR system continuously
monitors emissions reduction
performance and SCR system
malfunction (Type A or Type B).
When a malfunction or incorrect
fluid (such as water or low
concentrated DEF, etc.) is detected,
the SCR system will turn on warning
and indicator lights to encourage
you to have the condition corrected.
In the case of incorrect fluid or if an
SCR system malfunction (Type A) is
detected, continuing to drive for too long after these lights come on may
eventually result in a severe vehicle
speed limitation.
The following is a summary of the
warning lights, indicator lights and
restrictions. When these warning
and indicator lights come on the
DIC, promptly have the vehicle
inspected and serviced at a dealer.
In the case of SCR system
malfunction (Type B), have the
vehicle inspected and serviced at a
dealer.

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 193
Remarks:
*1–The warning buzzer continues
to sound every 5 minutes.
*2 –The warning buzzer continues
to sound every 5 minutes and when
driving 8 km (5 miles) or more, the
buzzer changes its sound to
continuous beeping.
When the exhaust system warning
light comes on DIC, promptly have
the vehicle inspected and serviced
at a dealer.
Stage 1 : When incorrect DEF or an
SCR system malfunction (Type A) is
detected, the warning and indicator
lights will come on as shown in the
table and engine power will be
reduced so the vehicle speed will
not exceed 89 km/h (55 MPH).
Stage 2 : If driving is continued for
another approximately
160 km (100 miles), the warning and
indicator lights will begin blinking.
Again, engine power will be reduced
so the vehicle speed will not exceed
56 km/h (35 MPH). Stage 3 :
If driving is continued for
approximately
105 more km (65 miles), the warning
and indicator lights will begin to
blink faster. Engine power will still
be reduced so the vehicle speed will
not exceed 56 km/h (35 MPH). The
vehicle speed will be limited to
8 km/h (5 MPH) either when the
vehicle is stopped after driving
further on (approximately
8 km (5 miles)) or when the engine
is restarted.
Stage 4 : DEF indicator light is
blinking quickly, the other warning
lights are on and the buzzer is
beeping continuously indicates the
vehicle speed is limited to 8 km/h (5
MPH). See Vehicle Messages 074,
Malfunction Indicator Lamp (Check
Engine Light) 061, Diesel Exhaust
Fluid (DEF) Warning Light 068, and
Reduced Engine Power Light 069.

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
196 Driving and Operating
When the exhaust system warning
light comes on, promptly have the
vehicle inspected and serviced at a
dealer.
When a malfunction is detected in
the SCR system, the warning and
the indicator lights shown in the
table come on. SeeVehicle
Messages 074, Malfunction
Indicator Lamp (Check Engine
Light) 061, and Diesel Exhaust
Fluid (DEF) Warning Light 068.
When the Diesel Exhaust Fluid
(DEF) Tank is Empty
If the DEF tank is empty and
warning and indicator lights are on,
you must follow below procedure to
cancel the vehicle restriction: 1. Turn the engine control switch to the LOCK or ACC position,
and add DEF.
2. After adding DEF, turn the engine control switch to ON
position.
3. Wait until buzzer stops, warnings and indicators are
turned 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.
5. Restart the engine.
It may take a while until the warning
lights and indicators turn off and the
buzzer stops after turning the
engine control switch to the ON
position.
It is desirable to fill up the tank with
DEF to avoid DEF remaining level
warning indication from reappearing.
When the outside temperature is
low, refer to Adding DEF in Cold
Weather. See Driver Information
Center (DIC) 070, Brake System
Warning Light (Parking Brake Light)
0 62, Warning Buzzers 079, and
Winter Driving 0142.Automatic
Transmission
On an automatic transmission
vehicle, the driver does not use a
clutch pedal when pulling away,
changing gears, or stopping. Only
the selector lever, accelerator pedal,
and brake pedal are used.
Practice learning the characteristics
of the automatic transmission
vehicle and how to correctly operate
it. When the vehicle is stationary,
remember to keep the brake pedal
firmly pressed, and if necessary,
move the selector lever in the P or
N position and apply the parking
brake.
Creep : With the engine running
and a gear position other than P or
N selected with the selector lever,
power reaches the wheels even
when the accelerator pedal is not
pressed, causing the vehicle to tend
to move.

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
Vehicle Care 269
Bulb Wattage
PositionLights Bulb Wattage (12V)Qty.
Front Headlight Highbeam/Lowbeam 60/55W2
Front Turn Signal Lamp 27W (Amber)2
Parking Lamp 5W2
Cornering Lamp 27W2
Side Turn Signal Lamp 5W (Amber)2
Sidemarker Lamp 5W (Amber)2
Rear Taillamp and Stoplamp 8/27W2
Turn Signal Lamp 27W2
Back-Up Lamp 27W2
License Plate Lamp 7.5W1
Roof Roofmarker Lamp (Identification/Clearance Lamp) 5W
5
Interior Dome Light 10W1
Speedometer and Gauge Lights 3.4W5
Warning/Indicator Lights LED20
Contact your dealer when replacing
lights that are not listed here.