2020 CHEVROLET LOW CAB FORWARD ECU

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 305
Towing the Vehicle
Consult your dealer or a
professional towing service if the
disabled vehicle must be towed.
Proper equipment must be used to
prevent damage to vehicles during
any towing. State and local laws
which apply to vehicles in tow must
be followed. Vehicles should not be
towed at speeds in excess of
88 km/h (55 mph).
Connect to the main structural parts
of the vehicle. Do not attach to
bumpers, tow hooks or brackets.
Use only equipment designed for
this purpose. Follow the instructions
of the wrecker manufacturer.
A safety chain system must
be used.
The procedures below must be
followed when towing to prevent
possible damage.Front End Towing (Front Wheels
Off Ground)
To prepare a disabled vehicle for
front end towing with front wheels
raised off the ground, the following
steps are necessary:
.
Block the rear wheels of the
disabled vehicle.
. Disconnect the driveshaft at the
rear axle. Secure the driveshaft
to the frame or crossmember.
When towing, disconnect the
driveshaft at the rear axle to ensure
the transmission is not damaged.
The rear end of the driveshaft must
be disconnected and safely secured
if the 80 km (50 mi) or 48 km/h
(30 mph) is exceeded.
If there is damage or suspected
damage to the rear axle, remove the
axle shafts. Cover the hub openings
to prevent the loss of lubricant or
entry of dirt or foreign objects.
Place a 10 cm (4 in) wood beam
against the towing guide behind the
bumper. (If no 10 cm (4 in) is
available, then remove the bumper.) Ensure towing chains do not come
into contact with the horns or the
bumper. (If towing chains contact
the bumper, then remove the
bumper.)
1. Horns
2. Bumper
After Towing
After towing the vehicle, block the
rear wheels and install axle shafts
or driveshaft.
Apply the parking brake before
disconnecting from the towing
vehicle.

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
306 Vehicle Care
Front End Towing (All Wheels On
the Ground)
Your vehicle may be towed on all
wheels provided the steering is
operable. Remember that power
steering and brakes will not have
power assist. There must be a tow
bar installed between the tow
vehicle and the disabled vehicle.
Towing with all wheels on theground
1. Bumper
2. Tow Hook
3. Front Axle
4. Towing Guide
5. Towing Chain
To prepare a disabled vehicle for
front end towing with all wheels on
the ground, the following steps are
necessary:
.Block the rear wheels of the
disabled vehicle.
. Disconnect the driveshaft at the
rear axle. Secure the driveshaft
to the frame or crossmember.
When towing, disconnect the
driveshaft at the rear axle to ensure
the transmission is not damaged.
The rear end of the driveshaft must
be disconnected and safely secured
if the 80 km (50 mi) or 48 km/h
(30 mph) is exceeded.
Provide wood blocking to prevent
towing chains and bar from coming
into contact with the bumper.
If there is damage or suspected
damage to the rear axle, remove the
axle shafts.
Cover the hub openings to prevent
the loss of lubricant or entry of dirt
or foreign objects. After Towing
After towing the vehicle, block the
rear wheels and install axle shafts
or driveshaft.
Apply the parking brake before
disconnecting from the towing
vehicle. Check and fill rear axle with
oil, if required.
Rear End Towing
When towing a vehicle with rear
wheels raised, secure the steering
wheel to maintain straight-ahead
position. Make certain that the front
axle is not loaded beyond the front
axle gross axle weight rating
(GAWR) as indicated on the
vehicle's VIN and weight rating
plate.
Special Towing Instructions
1. All state and local laws regarding such items as
warning signals, night
illumination, speed, etc., must
be followed.
2. Safety chains must be used.

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 307
3. No vehicle should ever betowed over 88 km/h (55 mph).
4. Loose or protruding parts of damaged vehicles should be
secured prior to moving.
5. A safety chain system completely independent of the
primary lifting and towing
attachment must be used.
6. Operators should refrain from going under a vehicle which is
being lifted by the towing
equipment unless the vehicle is
adequately supported by safety
stands.
7. No towing operation which for any reason jeopardizes the
safety of the wrecker operator
or any bystanders or other
motorists should be attempted.Appearance Care
Exterior Care
Exterior Finish
The paint finish on your vehicle
provides beauty, depth of color,
gloss retention and durability.
While cleaning the vehicle, do not
grip the roof marker lights to prevent
damage or water leakage.
Washing
The best way to preserve your
vehicle's finish is to keep it clean by
washing it often.
Wash the vehicle in lukewarm or
cold water. Do not use hot water or
wash your vehicle in the direct rays
of the sun. Do not use strong soap
or chemical detergents. All cleaning
agents should be flushed promptly
from the surface and not allowed to
dry on the finish.
These vehicles are designed to
operate under normal environmental
conditions to withstand natural
elements. However, unusual conditions such as high-pressure
car washers may cause water to
enter inside the vehicle. If the
vehicle is operated with foreign
material adhering to the exterior,
this material may react chemically
with paint, resulting in staining,
discoloration, rusting or corrosion of
components. Also, the material may
become trapped within mechanical
components, adversely affecting
their functions or forming an
aerodynamic resistance. In the
following cases, therefore, the
vehicle must be washed and all
foreign matter removed.
.
When soot, iron powder, dead
bugs, bird droppings, tree sap or
oily matter from coal tar and
smoke has adhered to painted
surfaces.
. When the vehicle has been
driven in coastal areas.
. When the vehicle has been
driven on roads where road
chemicals have been applied.
. When a large amount of mud or
dirt has adhered to the exterior.

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
330 Service and Maintenance
Owner Checks and
Services
Before Driving
Proper care and driving is important
not only for extended service life of
your vehicle, but also for improved
fuel and oil economy. Drive carefully
and defensively. Be sure you know
how to use your truck and its
equipment before operating it.
Starting and Operating
Proper care and operation will not
only extend the service life of your
vehicle but also improve fuel
economy.
Check Around the Vehicle Before
Starting the Engine
Before pulling away, perform a
thorough safety check, making sure
there are no children or obstructions
around the vehicle.
Take off the chocks after confirming
that the parking brake is securely
applied. Sit behind the wheel, adjust
the seat position, and buckle up theseat belt. The passengers are also
required to buckle up the seat belts.
Adjust the positions of the steering
wheel and mirrors. Lock the doors.
Turn the power of the dome light or
accessories OFF before starting the
engine.
Engine Conditions
Checking the Engine for
Startability and Abnormal Noises
1. Make sure the parking brake is securely engaged. Step firmly
on the brake pedal.
2. Make sure the selector lever is in "P" or "N" position.
For safety, firmly press the
brake pedal before starting the
engine.
3. Turn the engine control switch to start the engine.
Check that the engine starts
quickly with no abnormal
noises. Checking Condition of the Engine
at Low Speeds and during
Acceleration
1. Make sure the transmission is in the "P" or "N" position and
the parking brake is securely
engaged.
2. Turn the engine control switch to start the engine, and run it to
warm up.
3. Check that the engine is running at a speed within the
standard idle speed range.
During regeneration of the
diesel particulate filter (DPF),
the engine idle speed may
increase.
4. Drive the vehicle, making sure the accelerator pedal does not
stick when gradually
accelerating, the engine speed
rises smoothly and it does not
knock.

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
356 Customer Information
Customer
Information
Customer Information
Customer SatisfactionProcedure . . . . . . . . . . . . . . . . . . . 356
Customer Assistance Offices . . . . . . . . . . . . . . . . . . . . . . 357
Customer Assistance for Text Telephone (TTY) Users . . . . . 357
Online Owner Center . . . . . . . . . 357
GM Mobility Reimbursement Program . . . . . . . . . . . . . . . . . . . . 358
Roadside Assistance Program . . . . . . . . . . . . . . . . . . . . 358
Scheduling Service Appointments . . . . . . . . . . . . . . . 359
Collision Damage Repair . . . . . 359
Publication Ordering Information . . . . . . . . . . . . . . . . . . 362
Radio Frequency Statement . . . . . . . . . . . . . . . . . . . 362
Reporting Safety Defects
Reporting Safety Defects tothe United States
Government . . . . . . . . . . . . . . . . . 363
Reporting Safety Defects to General Motors . . . . . . . . . . . . . 363
Vehicle Data Recording and
Privacy
Vehicle Data Recording and
Privacy . . . . . . . . . . . . . . . . . . . . . . 363
Cybersecurity . . . . . . . . . . . . . . . . . 364
Customer Information
Customer Satisfaction
Procedure
Your satisfaction and goodwill are
important to your dealer and to
Chevrolet. Normally, any concerns
with the sales transaction or the
operation of the Chevrolet chassis,
or upfitted rear body will be resolved
by your dealer's sales or service
departments. Sometimes, however,
despite the best intentions of all
concerned, misunderstandings can
occur. If your concern has not been
resolved to your satisfaction, the
following steps should be taken:
STEP ONE : Discuss your concern
with a member of dealership
management. Normally, concerns
can be quickly resolved at that level.
If the matter has already been
reviewed with the sales, service,
or parts manager, contact the owner
of your dealership or the general
manager.

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
364 Customer Information
Cybersecurity
GM collects information about the
use of your vehicle including
operational and safety related
information. We collect this
information to provide, evaluate,
improve, and troubleshoot our
products and services and to
develop new products and services.
The protection of vehicle electronics
systems and customer data from
unauthorized outside electronic
access or control is important to
GM. GM maintains appropriate
security standards, practices,
guidelines and controls aimed at
defending the vehicle and the
vehicle service ecosystem against
unauthorized electronic access,
detecting possible malicious activity
in related networks, and responding
to suspected cybersecurity incidents
in a timely, coordinated and effective
manner. Security incidents could
impact your safety or compromise
your private data. To minimize
security risks, please do not connect
your vehicle electronic systems to
unauthorized devices or connectyour vehicle to any unknown or
untrusted networks (such as
Bluetooth, WIFI or similar
technology). In the event you
suspect any security incident
impacting your data or the safe
operation of your vehicle, please
stop operating your vehicle and
contact your 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
366 Index
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . 253Antilock . . . . . . . . . . . . . . . . . . . . . . . 207
Exhaust Light . . . . . . . . . . . . . . . . . . . 65
Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 258
Parking . . . . . . . . . . . . . . . . . . . . . . . .211
Braking . . . . . . . . . . . . . . . . . . . . . . . . . 134
Break-In, New Vehicle . . . . . . . . . . 156
Bulb Replacement Headlamp Aiming . . . . . . . . . . . . . 267
Headlamps . . . . . . . . . . . . . . . . . . . 267
Headlamps and Front TurnSignal . . . . . . . . . . . . . . . . . . . . . . . 270
Interior Lamps . . . . . . . . . . . . . . . . 277
License Plate Lamps . . . . . . . . . 276
Roofmarker Lamps . . . . . . . . . . . 274
Sidemarker Lamps . . . . . . . . . . . 274
Taillamps, Turn Signal, Stoplamps, and Back-up
Lamps . . . . . . . . . . . . . . . . . . . . . . 276
Buzzers, Warning . . . . . . . . . . . . . . . . 79
C
Cab Tilting . . . . . . . . . . . . . . . . . . . . . . 233
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . 230 California
Proposition
65 Warning . . . . . . . . . .230, 259, 301,
Back Cover
Capacities and Specifications . . . . . . . . . . . . . . . . . 349
Carbon Monoxide
Engine Exhaust . . . . . . . . . . . . . . . 168
Winter Driving . . . . . . . . . . . . . . . . 142
Cargo Lamp . . . . . . . . . . . . . . . . . . . . . 84
Caution, Danger, and Warning . . . . 3
CD Player . . . . . . . . . . . . . . . . . . . . . . . 90
Check Engine Light (MalfunctionIndicator) . . . . . . . . . . . . . . . . . . . . . . 61
Child Restraints
Systems . . . . . . . . . . . . . . . . . . . . . . . . 39
Cleaning Exterior Care . . . . . . . . . . . . . . . . . 307
Interior Care . . . . . . . . . . . . . . . . . . 313
Climate Control Systems . . . . . . . 121
Air Conditioning . . . . . . . . . . . . . . 121
Heating . . . . . . . . . . . . . . . . . . . . . . . 121
Cluster, Instrument . . . . . . . . . . . . . . 57
Cold Weather Operation . . . . . . . . 221
Collision Damage Repair . . . . . . . 359 Compartments
Storage . . . . . . . . . . . . . . . . . . . . . . . . . 42
Control of a Vehicle . . . . . . . . . . . . . 130
Coolant Engine . . . . . . . . . . . . . . . . . . . . . . . . 243
Engine Temperature Gauge . . . . 60
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . 121
Cornering Lamps . . . . . . . . . . . . . . . . 83
Cover
Engine . . . . . . . . . . . . . . . . . . . . . . . . 235
Covers
Winter . . . . . . . . . . . . . . . . . . . . . . . . 163
Cruise Control . . . . . . . . . . . . . . . . . . 214 Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Cupholders . . . . . . . . . . . . . . . . . . . . . . 44
Customer Assistance . . . . . . . . . . . 357 Offices . . . . . . . . . . . . . . . . . . . . . . . . 357
Text Telephone (TTY)Users . . . . . . . . . . . . . . . . . . . . . . . 357
Customer Information Publications Ordering
Information . . . . . . . . . . . . . . . . . . 362
Customer Satisfaction Procedure . . . . . . . . . . . . . . . . . . . . . 356
Cybersecurity . . . . . . . . . . . . . . . . . . . 364

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
370 Index
P
ParkingBrake . . . . . . . . . . . . . . . . . . . . . . . . . .211
Over Things That Burn . . . . . . . 167
Passenger Compartment Air
Filter . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Pedals . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Perchlorate Materials Requirements, California . . . . . . 230
Phone
Bluetooth . . . . . . . . . . . . . . . . . . . . . . 111
Port USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Power
Door Locks . . . . . . . . . . . . . . . . . . . . . 21
Outlets . . . . . . . . . . . . . . . . . . . . . . . . . 55
Reduced Engine Light . . . . . . . . . . 69
Steering Fluid . . . . . . . . . . . . . . . . . 252
Windows . . . . . . . . . . . . . . . . . . . . . . . 23
Power Take-Off (PTO) . . . . . . . . . . 227
Pregnancy, Using Seat Belts . . . . 35
Privacy Vehicle Data Recording . . . . . . . 363
Proposition
65 Warning,
California . . . . . . . . . . . .230, 259, 301, Back CoverPublication Ordering
Information . . . . . . . . . . . . . . . . . . . . 362
R
Radio Frequency Statement . . . . 362
Radio Reception . . . . . . . . . . . . . . . . . 89
Radios
AM-FM Radio . . . . . . . . . . . . . . . . . . . 85
Rear Axle . . . . . . . . . . . . . . . . . . 261, 262
Rear Seats . . . . . . . . . . . . . . . . . . . . . . 30
Rear Storage . . . . . . . . . . . . . . . . . . . . 45
Recommended Fluids and Lubricants . . . . . . . . . . . . . . . . . . . . . 339
Reduced Engine Power Light . . . . 69
Reimbursement Program, GM Mobility . . . . . . . . . . . . . . . . . . . 358
Remote Keyless Entry (RKE)
System . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacement Parts Maintenance . . . . . . . . . . . . . . . . . . 341
Reporting Safety Defects
General Motors . . . . . . . . . . . . . . . 363
U.S. Government . . . . . . . . . . . . . 363
Roads Driving, Wet . . . . . . . . . . . . . . . . . . 140
Roadside Assistance
Program . . . . . . . . . . . . . . . . . . . . . . . 358
Roofmarker Lamps . . . . . . . . . . . . . 274 Rotation, Tires . . . . . . . . . . . . . . . . . . 297
Routing, Engine Drive Belt . . . . . . 355
Running out of Fuel . . . . . . . . . . . . . 224
Running the Vehicle While
Parked . . . . . . . . . . . . . . . . . . . . . . . . 170
S
Safety Defects ReportingGeneral Motors . . . . . . . . . . . . . . . 363
U.S. Government . . . . . . . . . . . . . 363
Safety System Check . . . . . . . . . . . . 37
Scheduling Appointments . . . . . . . 359
Seat Belts . . . . . . . . . . . . . . . . . . . . . . . 31 Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Extender . . . . . . . . . . . . . . . . . . . . . . . . 37
Lap Belt . . . . . . . . . . . . . . . . . . . . . . . . 36
Reminders . . . . . . . . . . . . . . . . . . . . . . 60
Three-Point . . . . . . . . . . . . . . . . . . . . . 33
Use During Pregnancy . . . . . . . . . . 35
Seats Position, Front . . . . . . . . . . . . . . . . . . 26
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Security Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . 21
Selector Lever . . . . . . . . . . . . . . . . . . 205
Service . . . . . . . . . . . . . . . . . . . . . . . . . 126 Accessories andModifications . . . . . . . . . . . . . . . . 230