ECU 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
Vehicle Care 243
.Dipstick H (HOT) —
Transmission fluid
temperature Approx. 70 -
80 °C (158 - 176 °F).
. The “C (COLD)” range on
the dipstick is a guide used
by your dealer for
specialized equipment used
to replace or service the
automatic transmission
fluid. When performing your
own inspections, always
use the “H (HOT)” range
after warming up the
vehicle.
The fluid must be hot to
ensure an accurate check.
The fluid level rises as
temperature increases.
6. If the fluid level is too low, add the specified fluid through the
dipstick guide tube. Also, check
whether there are no fluid
leaks.
7. Insert the dipstick securely into position.{Warning
Be extremely careful not to burn
yourself when checking the oil
level if the engine temperature is
high. Protect yourself with
gloves etc.
You and others could be seriously
injured.
Discarded parts, oil, grease and
fluids could have an adverse effect
on the environment. It is difficult to
dispose of these, so have your
dealer handle all checks and
replacements.
Engine Air Cleaner/Filter
Air Cleaner
Using a clogged air cleaner element
not only reduces engine output but
also causes increased fuel
consumption and an increased DPF
regeneration frequency. Be sure to use a genuine air cleaner
element. If a different air cleaner
element is used, it may cause the
sensor to output a wrong signal.
See
Maintenance Schedule 0317.
Air Cleaner Indicator Light
When the air cleaner indicator light
comes on, check the air cleaner
element. If the air cleaner element is
clogged, replace the air cleaner
element.
See Vehicle Messages 074.
See Maintenance Schedule 0317.
Engine Coolant
Protection of Engine Against
Overcooling
Overcooling of the engine not only
accelerates wear of the vital engine
parts but also hurts fuel economy.

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
246 Vehicle Care
{Warning
For storage, close the cap of
coolant container securely and
keep it in a place inaccessible to
children.
You and others could be seriously
injured.
Using any coolant other than that
recommended by your dealer could
cause damage to the engine,
radiator or heater core. In particular,
use of coolants containing borate
salts or silicates may result in
engine or radiator corrosion,
causing engine coolant leaks and
other problems.
To dilute the coolant, use distilled
water or deionized water.
Do not use the coolant at any
coolant concentration other than
that specified. If the coolant
concentration is 60% or higher,
overheating is likely to occur, while
if it is 30% or lower, anti-corrosion
function is not provided sufficiently. Using coolant at any coolant
concentration other than that
specified may reduce anti-freezing
performance, and engine coolant
may freeze.
If the engine coolant decreases
rapidly, stop the vehicle in a safe
place and contact your dealer for
advice and repair.
Checking the Engine Coolant
Level
For the single cab model, the
engine coolant reserve tank is
located behind the front-right wheel.
See
Cab Tilting 0233.
For the crew cab model, the engine
coolant reserve tank is under the
access panel beneath the left rear
seat. See Engine Cover 0235.
When the engine has cooled down,
make sure that the fluid level in the
engine coolant reserve tank is no
lower than the “MIN”line. In
addition, carefully remove the
radiator cap and check to see if it is
damaged. Check that the engine
coolant is full to the filler neck.
Check the engine coolant level only
when it is cold.

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 247
The radiator cap (1) opens and
closes in double action. When
removing the radiator cap, take
caution not to damage the cap and
the filler neck (2).
Turn the cap slowly to the left until it
reaches a“stop”. Do not press down
while turning the cap.
Wait until any remaining pressure
(indicated by a hissing sound) is
relieved, then press down on the
cap and continue turning it to
the left.
Also, check to make sure there are
no leaks from the radiator or
radiator hose. Check for fluid or stains on the ground showing leaks
where the vehicle is parked. Contact
your dealer if you discover leaks.
Using the vehicle when there are
leaks can lead to engine seizure.
Adding Engine Coolant
Single Cab Model
Crew Cab Model
When the engine coolant level in the
engine coolant reserve tank is
below the “MIN”line, open the
reserve tank cap and fill to near the
“MAX” line with engine coolant.
Wash the reserve tank cap and filler
neck with clean water. Tighten the
cap securely after the engine
coolant has been replenished.

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
252 Vehicle Care
Power Steering Fluid
The power steering fluid level must
be checked and it must be changed
according to the Maintenance
Schedule. SeeMaintenance
Schedule 0317.
When replenishing power steering
fluid or flushing the power steering
system, always use ATF
(Dexron
®-VI). Failure to use the
proper fluid may damage the power
steering system seals and hoses,
leading to fluid leakage.
Checking the Power Steering
Fluid Level
The fluid level is correct if it is
between the “MAX”and“MIN” lines
on the power steering fluid tank.
If the level is lower that the “MIN”
line, add fluid up to the “MAX”line.
The reserve tank is located at the
rear of the engine compartment on
the right. When you have finished
checking the fluid level, securely
reinstall the cap and cover.
{Warning
Before adding fluid, clean the
area around the cap and pour
fluid from a clean jug or filler.
Foreign matter getting in the tank
may cause power steering system
failure.
Do not mix the recommended
power steering fluid with fluids of
other brands. Due to chemical
reactions, any mixture of
differently branded fluids may
cause failure of the system.
You and others could be seriously
injured.
Washer Fluid
Windshield Washer Fluid
The windshield washer is equipped
on the windshield wiper arm.
Check the level of fluid in the
windshield washer fluid tank. In
addition, spray windshield washer
fluid and operate the windshield
wipers to check for any areas not

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
258 Vehicle Care
free of any type of damage. Check
the right front brake hose and pipe
in the same way. The rear left and
right brake hoses and pipes should
also be checked in the same
manner.
Disc Brakes and Drum Brakes
If the brake pads and shoe linings
wear out beyond their usable limit,
not only will the brake performance
be impaired, but brake components
could also fail.
{Warning
Do not drive with brake pads and
shoe linings worn out beyond the
limit. Excessively worn brake
pads and shoe linings may cause
breakdown of brake components
and poor braking performance.
You and others could be seriously
injured.
Caution
The pad has an embedded wear
indicator. A squeaking noise from
the indicator means that the pad
is approaching the usable limit.
If the squeaking noise from the
indicator can be heard, contact
the nearest dealer for inspection
or replacement.
Brake Fluid
Checking the Brake Fluid
Level
Remove the inspection cover (1) on
the left- hand side of the instrument
panel by turning it with your fingers.
Check that the fluid level in the
reservoir is between the "MAX" and
"ADD" lines.
If the fluid surface cannot easily be
seen, rock the vehicle gently.
Adding Brake Fluid
If the level of brake fluid has
dropped below the "ADD" line,
remove the cap (2) and add fluid.
Take care to avoid filling beyond the
"MAX" line.
Tighten the cap securely after the
fluid has been added.
When adding brake fluid to the tank,
take care to prevent dirt and water
from entering it. Any dirt or water in
the system could cause the vehicle
to lose braking functions.
Inspect and change brake fluid
according to the Maintenance
Schedule.
Use the recommended brake fluid
when adding brake fluid.

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
264 Vehicle Care
Automatic Transmission
Shift Lock Control
Function Check
When the Selector Lever
Cannot be Moved From the "P"
Position
Perform the following when the
selector lever cannot be moved from
the "P" position.
Caution
When the selector cannot be
operated from the P position to
any other position even after
performing the operation below
repeatedly, the shift lock system
may have a failure. Have the
vehicle inspected at your dealer.
When performing the below
operations, make sure the parking
brake is securely engaged. 1. Securely pull the parking brake lever and stop the engine.
2. Remove the cup holder (1) byremoving the three Torx®
bolts (2).
3. Remove the selector levercover by removing the four
screws and lifting it up.
4. Operate the selector lever (1)
while pressing the release
lever (2).
When installing the cover, perform
the removal procedure in reverse
order.

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 267
2. Continue pushing in the wiperrubber insert until the wiper
blade's hook engages with the
hole in it, and then confirm that
the rubber insert is securely
held in place.
3. Attach the wiper blade to the wiper arm.Headlamp Aiming
For vertical aiming, turn the two
screws indicated by arrows in the
diagram.
1. Remove the rubber beneath the headlight.
2. Two screws should be turned in the same direction at the
same time to adjust aiming.
3. When the headlamp aiming is out of position, contact your
dealer.
Bulb Replacement
Caution
Do not replace incandescent
bulbs with aftermarket LED
replacement bulbs. This can
cause damage to the vehicle
electrical system.
Bulbs
1. Check each bulb for blowout.
2. If a bulb has blown out, replaceit. Always place the engine
control switch in the “LOCK”
position and place all the other
switches in the “OFF”position
before replacing the blown
bulbs.
3. If you need assistance replacing any bulbs, contact
your dealer.
Turn Signals
The flasher unit activates both the
turn signal circuits and the hazard
circuit. Should a lamp burn out, the

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
272 Vehicle Care
8. Remove the rubber boot (2).Push the right side of the
clip (1) that holds the bulb (3)
in place and slide it upwards to
disengage the clip.9. Remove the bulb (1) from thesocket (2) and replace with a
new one.
10. After replacing the bulb, reverse steps 1-8 to install.
Do not touch the glass of the bulb
with your hand. Soiling the glass will
cause the bulb to blow out.
When attaching the rubber boot,
press in both the outside and inside
circumference of it. Make sure that
the rubber boot, the headlamp
assembly, and the bulb are securely
installed without any raised section. If the rubber boot is not firmly in
place, water could get inside the
headlamp and lead to a breakdown.
Replacing Parking Lamps
1. Refer to
“Replacing the
Headlamps” and remove the
headlamp assembly.
2. Pull the bulb out from the parking lamp socket and
replace with a new one.

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 273
3. To install the lamps, performthe same sequence of
operations in reverse, taking
care to turn the connector
clockwise to lock it securely.
If the socket is not locked securely,
water could get inside the lamp and
lead to a breakdown.
Replacing a Front Turn
Signal Lamp
Do not replace a bulb with other
than the specified wattage. This will
cause abnormal flashing,
particularly for turn signal lamps.
When replacing a bulb, make sure
the light switch is OFF.
1. While referring to “Replacing
the Headlights”, tilt the turn
signal lamp assembly down
toward the front of the vehicle
and remove it.
2. Disconnect the connector for the turn signal light and then
remove the socket.

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
274 Vehicle Care
3. Pull the bulb from the socketand replace it with a new one.
4. To install the lamps, perform the same sequence of
operations in reverse, taking
care to turn the connector
clockwise to lock it securely.
If the socket is not locked securely,
water could get inside the light and
lead to a breakdown.
Roofmarker Lamps
1. Loosen the screws (2) and remove the lens (1). 2. Remove the bulb (3) from the
socket (4) and replace it with a
new one.
3. To install the lights, follow the removal procedure in reverse.
If the screwing procedure is
inadequate, water may infiltrate into
the lamp unit.
Sidemarker Lamps
(Including Turn Signal
and Cornering Lamps)
Do not replace a bulb with other
than the specified wattage. This will
cause abnormal flashing,
particularly for turn signal lamps.
When replacing a bulb, make sure
the light switch is "OFF".
1. Open the front door, remove the rubber cap (1) in the lower
part of the door, and loosen
the nut (2).