light CHEVROLET LOW CAB FORWARD 2020 Owners Manual

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
Driving and Operating 201
Driving conditionsSelector lever position
Normal uphill road D (overdrive off switch ON)
Steep uphill, steep slope, mountain
road with many sharp curves 2 or 1
Long uphill road 2
Downhill driving:
Do not overuse the foot brake. This
will cause the brakes to overheat,
reducing their effectiveness. On
long downward slopes or sharp
downhill sections of road, use the
engine brake together with the foot
brakes to control the speed.
When the selector lever is in the D
position, you can drive with the
overdrive off switch ON to allow a
gentle engine brake to be applied.
Push the overdrive off switch to the
ON position at speeds below
101 km/h (63 MPH) to increase
engine braking action when
traveling downgrade. You can increase engine braking by
driving with the selector lever in the
2 position.
To apply a stronger engine brake on
sharp downhill sections, shift the
selector lever to the 1 position when
required.
See
Control of a Vehicle 0130.
Driving at Low Speeds for
Sustained Periods
Any low speed applications such as
sweeper, road marking machinery,
trash collectors, highway striping or
moving, etc. require the following
treatment to prevent the automatic
transmission fluid (ATF) from
overheating:
Select 1 position during low speed
operation under 18 km/h (11 MPH). Select 2 position during low speed
operation under 36 km/h (22 MPH).
See
Automatic Transmission Fluid
Temperature Warning Light 066.
To Stop Your Vehicle 1. To temporarily stop the vehicle, press the brake pedal firmly
while the selector lever is in D.
2. Use the parking brake as required. Press the brake pedal
firmly, and firmly apply the
parking brake.
If the vehicle is stationary for a
long time, move the selector
lever into the N or P position.
If the selector lever is kept in
D, the temperature of the
automatic transmission fluid
increases due to heat from the
torque converter.
To ensure reliable brake application,
be sure to use your right foot to
press the brake pedal.
When leaving the driver's seat,
follow the When Parking Your
Vehicle procedure.

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
206 Driving and Operating
For safety reasons, the shift lock
system operates to prevent shifting
of the selector lever to any position
other than P unless the brake pedal
is pressed and the starter switch is
in the ON position. When pulling
away, be sure to keep the brake
pedal pressed as you operate the
selector lever. SeeDriver
Information Center (DIC) 070,
Overdrive Off Light 066, Automatic
Transmission 0196, and Automatic
Transmission Shift Lock Control
Function Check 0264.
Overdrive Off
Overdrive Off Switch
Diesel vehicles have two overdrive
gears (5th and 6th). These two high
speed gears provide increased road
speed, low running noise and
outstanding fuel efficiency.
Take advantage of overdrive
whenever possible.
.
Use the overdrive during normal
driving. When driving down long
downhill roads that require the
engine brake, or when driving on mountain roads or through city
centers, release the overdrive.
Doing so will reduce the number
of gear changes making the ride
smoother.
. If your vehicle is traveling at a
speed exceeding
101 km/h (63 MPH), it is not
possible to downshift from 6th
gear to 5th gear.
. If your vehicle is traveling at a
speed exceeding
78 km/h (49 MPH), it is not
possible to downshift from 5th
gear to 4th gear.
Overdrive Off Switch : Under
normal circumstances, press the
overdrive off switch (3) to turn the
overdrive OFF (the overdrive off
indicator light comes on).
Press the switch again to release
the overdrive off (the overdrive off
indicator light goes off). See
Overdrive Off Light 066.

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 207
Overdrive Off Indicator Light
Indicator lightFunction Usage conditions
Goes Off. 6-Speed (4-speed + overdrive) automatic
change (Overdrive ON). Use under normal driving conditions.
Comes On. 4-speed automatic change, but no change to
overdrive (overdrive OFF). Used when a light engine brake is required.
Doing so will reduce the number of gear
changes making the ride smoother on roads
that have many hills.
. During cold weather, the
transmission may not shift to the
5th or 6th gear (overdrive) until
the engine warms up.
. Even if the engine is stopped
with the overdrive OFF, the
overdrive will be ON the next
time the engine is started.
Brakes
Antilock Brake
System (ABS)
Wheels may be locked and slip
during sudden braking or braking on
a slippery road surface such as a
snowy road. ABS is a device to
prevent the wheels from locking by
detecting a slippery condition during
braking and securing the directional
stability and handling stability of the
vehicle. ABS only assists in limited
road conditions and will not prevent
a crash if you exceed safe driving
speeds for road conditions. Always
drive safely.
{Warning
The braking distance on slippery
road surfaces is longer than that
on a normal dry paved road even
with an ABS-equipped vehicle. In
addition the braking distance can
be slightly longer in deep snow
and on a gravel road when ABS
is activated. Therefore, always
keep in mind the road condition
and tire condition (type of tires
and worn condition), observe safe
(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
208 Driving and Operating
Warning (Continued)
driving habits and drive the
vehicle while keeping a proper
distance between vehicles.
ABS does not prevent crashes if
you do not drive safely. Drive the
vehicle at a safe speed.
Install tires of the specified size,
same brand and same tread
design (including winter tires) on
all wheels. If different tires are
installed, the braking distance
becomes longer and directional
control stability of the vehicle
decreases. This is very
dangerous.
Steering during sudden braking
(when the ABS is working) will
feel slightly different than it does
when the brakes are not applied.
Operate the steering wheel
carefully keeping this in mind.
Driving in sand or on a muddy road
may adversely affect the brakes and
ABS sensors. Wash the vehicle to remove sand and mud after
operating the vehicle in sandy or
muddy conditions.
Before washing the vehicle, provide
necessary protection to prevent
water from being splashed on the
ABS components (sensors and
actuators). Especially when using
high-pressure washing, be careful
not to allow water to be directly
sprayed onto the ABS components
and their harness connectors.
These are not signs of ABS
malfunction:
.
Soon after you start the engine
and the vehicle starts moving,
the sound of motor or valve
working may be heard from the
rear of the vehicle or underside
of the cab. This sound is from a
self-check by the ABS system
and is normal. In addition, you
may also feel some vibration if
the brake pedal is pressed at
this time.
. When ABS is operating,
vibration is felt on the brake
pedal and steering wheel and you may hear the system
operating. This is normal when
ABS is properly operating.
. The exhaust brake may release
when ABS is activated and the
exhaust brake is in operation.
. ABS is more likely to be
activated when the brake is
applied during cornering or
driving over a bump. This is
because inside wheels or
wheels that have gone over a
bump tend to lock.
. ABS is not activated immediately
after starting the vehicle. It is
activated only when the vehicle
speed reaches approx. 10 km/h
(6 MPH). ABS operation is
inactive when the vehicle speed
reduces to approx. 5 km/h
(3 MPH).

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 209
ABS Operation Indications and
Signs
ABS warning light
Operation Indications of ABS
When the engine control switch is
placed into the "ON" position, the
ABS warning light comes on and
then goes out in approx. 3 seconds.
The ABS is normal if the warning
light goes out.
Operation Signs of ABS
When ABS is activated, slight
vibration is generated on the brake
pedal (hydraulic brake model) and
steering wheel, and an operating
sound can be heard from the ABS
equipment.
If the ABS warning light does any of
the following, the ABS may be
faulty. Please contact the nearest
dealer. ‐
If the ABS warning light comes
on during driving
‐ The light does not come on when
the engine control switch is
placed into the "ON" position
See Antilock Brake System
(ABS) Warning Light 064.
Even if a problem has occurred with
the ABS, the regular brakes will still
work normally. However, ABS will
not operate.
Precautions for Driving an
ABS-Equipped Vehicle
ABS is not a device that enables
driving and stopping under
conditions exceeding safe driving
limits. Always drive safely.
{Warning
When braking suddenly, continue
pressing brake pedal hard so that
the ABS can take effect. (Continued)
Warning (Continued)
When braking suddenly, do not
pump the brakes (pushing and
releasing the brake pedal little by
little). Pumping brakes will
increase the braking distance.
The braking distance on slippery
road surfaces is longer than that
on a normal dry paved road even
with an ABS-equipped vehicle.
When ABS is activated in the
following road surface conditions,
the braking distance may be
slightly longer compared to that of
vehicles not equipped with an
ABS. Therefore, always be aware
of the road and tire condition (tire
type and wear condition), observe
safe driving habits and drive the
vehicle while keeping a safe
following distance.
‐ When driving on a gravel
road, or a road with a deep
snow covering.
(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
210 Driving and Operating
Warning (Continued)
‐When tire chains are used.
‐ When driving over road
joints or bumps such as
light reflectors on the road.
‐ When driving on a bumpy
road, stone-paved road or
track.
‐ When driving over an iron
plate or manhole lid.
ABS does not work for wheel skid
during a standing start,
acceleration and cornering which
do not involve braking. On a very
slippery icy road, tires may lose
grip and steering wheel operation
may not be able to control the
vehicle's direction, resulting in
very unstable driving. Always
drive the vehicle observing a safe
speed well matched with both
road surface and tire conditions,
and avoid sudden braking. (Continued)
Warning (Continued)
If powerful engine braking is
applied on a very slippery icy
road, the drive wheels may be
locked (the ABS then does not
work), resulting in loss of vehicle
control.
When ABS is activated, a slight
vibration (especially when the
road surface is different between
right and left wheels) and pulling
may be felt on the brake pedal
and steering wheel. In addition,
an operating sound is produced
from the ABS actuators. This
does not indicate any abnormal
condition. Stay calm and operate
the steering wheel properly.
Electronic Braking force
Distribution (EBD)
EBD is a function that uses the ABS
to distribute braking force ideally
between the front and rear wheels
in order to compensate for changes
in load conditions or any shift of the load due to acceleration or
deceleration, thus preventing
premature locking of the rear
wheels.
{Warning
If a problem should occur with the
EBD function, the ABS warning
light and the brake system
warning light will come on
simultaneously.
The rear wheels will lock more
easily if there is a problem with
the EBD function. Have it
checked and serviced at the
nearest dealer as soon as
possible. You and others could be
seriously injured.
When the EBD operates, the brake
pedal may push back slightly or you
may hear a sound similar to that
generated by the ABS when
operational. Neither of them
indicates any abnormal condition.

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 211
Parking Brake
Parking Brake Lever
When parking or stopping your
vehicle, engage the parking brake
and make sure that the vehicle does
not start moving. Avoid parking your
vehicle on a slope as much as
possible and choose a level and flat
place. If parking on a slope is
unavoidable, be sure to set the
parking brake, make sure that the
vehicle does not move, and block
the wheels with chocks for added
safety.
Illumination of the parking brake
warning light does not mean that the
parking brake is fully applied. The
parking brake lever must be fully
engaged.
When you engage the parking brake
lever, air pressure is reduced and all
four wheel brakes are applied.
{Warning
Although the parking brake
indicator light will come on if the
parking brake is engaged while
the engine control switch is in the
ON position, this does not mean
the parking brake is fully
engaged, so always make sure
the lever is fully pulled up.
Never drive the vehicle with the
parking brake set as this will
cause excessive wear, reduce
parking brake effectiveness and
increase fuel consumption.
Choose a flat place where
stopping and parking are
permitted and where the vehicle
will not obstruct traffic.
Remove all dirt from the vehicle's
light lenses and reflectors to
ensure that the vehicle can be
seen from other vehicles. You and
others could be seriously injured.
Avoid parking for long periods with
cargo on the vehicle.
{Warning
Do not use the parking brake
while the vehicle is in motion
except in an emergency. Applying
the parking brake before the
vehicle has stopped can cause
the tires to lock or the vehicle to
spin, possibly causing an
accident. Unless the parking
brake is fully released during
driving, a fault and/or a fire may
result.
If it was necessary to use the
parking brake during driving, be
sure to check afterwards to
determine if any fault or failure
has resulted.

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
212 Driving and Operating
Operation of Parking Brake
The parking brake lever is located to
the right of the driver's seat.
To set the parking brake, completely
stop the vehicle. Then, without
pressing the release button (1), hold
the brake pedal down while pulling
the parking brake lever (2) all the
way up.The parking brake indicator light in
the instrument panel will come on
when the lever is pulled up. Before
you leave the driver's seat, follow
the steps under
“Parking, or Leaving
Driver's Seat”. See Braking0134.
To release the parking brake, hold
the brake pedal down while pushing
the release button of the parking
brake lever and lower the lever. The
parking brake indicator light in the
instrument panel will go out.
The parking brake indicator light is
designed to remind you if the
parking brake is not released when
the engine control switch is on.
If the parking brake warning light
remains on when the parking brake
lever is lowered, a brake failure or a
drop in air pressure may be the
cause.
Check the brake air pressure for
correct level. If the brake air
pressure is low, contact your local
Isuzu Dealer for service.
If you notice the parking brake lever
travel has increased over time, this
means the cable adjustment must be checked by a qualified
technician. Adjustment may be
required due to parking brake shoe
wear. See
Control of a Vehicle
0 130.
Inspection
Pull the parking brake lever slowly
from the fully released position while
counting the clicks produced as the
lever engages ratchet plate notches
to check that it can be raised the
proper amount and the lever is held
firmly.

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 213
If the number of notches is not
within the standard value range
below, adjust it to the standard
value. Lever stroke is 6 to 8
notches.
Number of notches before parking
brake is set when lever is pulled
slowly from released position with
pull force of about 147 N (15 kgf/
33 lbs). SeeMaintenance Schedule
0 317 and
Additional Maintenance and Care
0 336.
Exhaust Brake
Exhaust Brake Switch
When turned on, the system
increases the amount of power
absorbed by the engine while
coasting in gear. Whenever slowing
down the vehicle, such as on down
grades, in city traffic or approaching
stop signals, this brake system may
be used.
To turn on the exhaust brake system
while driving, pull the lever
backward. The exhaust brake
indicator light comes on. The
exhaust brake will engage
automatically when the accelerator
pedal is released and vehicle speed
is above 10 km/h (6.5 MPH). The exhaust brake will disengage
when the accelerator pedal or brake
pedal is pressed. Releasing the
pedal reengages the exhaust brake.
Push the lever forward to turn the
exhaust brake off during idling.
{Warning
It is extremely dangerous to apply
the exhaust brake on slippery
roads as the tires can skid.
You and others could be seriously
injured.
Even if the selector lever is placed
in the N position, the exhaust brake
does not disengage until the engine
is warmed up if the warm-up system
is on.