service CHEVROLET LOW CAB FORWARD 2018 User Guide

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Instruments and Controls 77
booster (HBB) becomes faulty. The
warning buzzer will stop sounding
when the parking brake is engaged.
On 4500HD and 4500XD, the brake
low vacuum warning light and
warning buzzer should come on to
indicate low vacuum reserve for
brake power assist. At the same
time, the Back up Electric Vacuum
Pump operates.
(5500HD, 5500XD models) When
the HBB pressure is low, and/or the
HBB fluid (Dexron–VI) level is low,
the light and warning buzzer should
come on. Do not use brake fluid in
the brake booster reservoir. Use
only Dexron –VI ATF.
If this happens while driving:
. Do not pump the brakes. The
system is designed to stop the
truck with reserve power assist if
the pedal is held down. This
reserve is greatly reduced each
time you apply and release the
brakes.
. Stopping distance may be
longer. .
You may have to push much
harder on the brake pedal.
. Have the vehicle repaired before
you continue driving.
The buzzer stops when the selector
lever is shifted to the P position.
{Warning
Do not drive while the buzzer
sounds as the brakes are not
operating to their full capacity.
You and others could be seriously
injured.
Antilock Brake System
(ABS) Warning Light
This light comes on briefly when the
engine control switch is turned to
the ON position, and then should go
out after approximately three seconds. If the light does not
come on, have it fixed so it will be
ready to warn if there is a problem.
This warning light comes on
together with the brake system
warning light whenever there is a
problem in the Anti-lock Brake
System (ABS). In this case, the ABS
stops working but the brakes still
function as ordinary service brakes.
{Warning
If this warning light comes on
while driving, immediately stop
your vehicle at a safe place well
clear of traffic and take the
following actions.
1. Stop the engine.
2. Restart the engine. Check ifthe ABS warning light
comes on and then goes
out. If it does, there is no
problem. The ABS operates
normally.
(Continued)

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
78 Instruments and Controls
Warning (Continued)
3. Move the vehicle slowlyforward. Gradually increase
the speed to 15 km/h
(9 mph). If the light goes off,
the ABS is normal.
If the light does not come on or
go out, or comes on frequently,
contact your dealer immediately
and have the system repaired.
Even if a problem has occurred in
the ABS, the brakes will still work
as normal brakes. In this case,
the ABS has no influence on the
operation of the brake system.
See Brake System Warning Light
(Parking Brake Light) 075 and
Antilock Brake System (ABS) 0196.
Exhaust Brake Light
This light comes on when the
exhaust switch is pulled and the
engine is running. See Exhaust
Brake 0201.
Service Transmission
Warning Light
This light comes on briefly when the
engine control switch is in the ON
position, as a check to show the
light is working. It should go out
when the engine is started. If the warning light starts to blink
while driving, it indicates that there
is a malfunction in the automatic
transmission’s electronic control
system. If the warning light is
blinking, see your dealer for service.
Automatic Transmission
Fluid Temperature
Warning Light
This light comes on briefly when the
engine control switch is in the ON
position, but the engine is not
running, as a check to show the
light is working. It should go out
when the engine is started.
The Automatic Transmission Fluid
(ATF) Temperature warning light
comes on if the ATF temperature is
high. This usually occurs when the
transmission is overfilled and may

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
80 Instruments and Controls
Check the oil level in the engine
crankcase. If the oil level is normal,
restrictions are in the oil filter or
within the lubricating system. Have
the vehicle inspected at your dealer.
Do not run the engine with this light
on. It could damage the engine.
When this light comes on while
driving, a warning tone also sounds.
The oil level varies while the engine
is running right after it has stopped
or if the vehicle is on uneven
ground. As a result, the red engine
oil pressure warning light may
light up.
When checking the oil level, press
the engine oil level check switch on
level ground while the engine is
cool. The red engine oil pressure
warning light in combination with the
green engine oil level indicator light
can indicate if the engine oil level is
OK or low.
While driving, this light will also
activate the engine alarm and
automatic shutdown system.
SeeEngine Oil Level Indicator Light
0 80 and Engine Oil 0223.Engine Oil Level Indicator
Light
When the engine oil level check
switch is pushed with the engine
control switch in LOCK, the green
engine oil level indicator light will
come on if the engine oil level
is OK.
See Engine Oil Pressure Light 079
and Engine Oil 0223.
Diesel Exhaust Fluid
(DEF) Warning Light
This light should come on briefly
when the engine control switch is
turned to the ON position, and go off
when the engine has started.
This light comes on as a warning
related to the selective catalytic
reduction (SCR) system. If this light
comes on, check the DEF gauge.
Add DEF if necessary. If DEF level
is OK, have your vehicle serviced
by your dealer.
Also see Diesel Exhaust Fluid
0 170.
Engine Shutdown
Warning Light
The Engine Shutdown Warning light
comes on briefly when the engine
control switch is turned to the ON
position, as a check to show the
light is working. The light turns off
when the engine is started.

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
84 Instruments and Controls
Red means the battery voltage is
too low or too high. If the voltmeter
sign appears in red, have the
vehicle checked and serviced at
your dealer. During or immediately
after the engine is started, a red
abnormal L voltage may display on
the DIC. If the warning disappears
after the engine has started, there is
no problem with the battery voltage.
Calendar and Clock
{Warning
The calendar and clock can be
set only while the vehicle is
stationary. When setting the
calendar or clock, park your
vehicle in a safe place where
stopping or parking is permitted
and that is well clear of traffic.
Press the DIC selector once or
more to select the calendar. Press
and hold the DIC selector to enter
the clock setting screen. The year
segment will flash. Turn the DIC
selector clockwise or
counterclockwise to increase or decrease the year. While in the year
setting screen, press the DIC
selector once to switch to the month
setting screen. The month segment
will flash. Use the same method to
set the month. While in the month
setting screen, press the DIC
selector again to switch to the day
setting mode. Adjust the day using
the selector.
Press and hold the DIC selector to
complete the calendar setting.
When complete, the normal
calendar display will resume. Use
this same method to set the hour
and minute when in the clock setting
screen.
Dimmer
The brightness of the DIC can be
adjusted while the light control
switch is off. Select this screen and
turn the DIC selector clockwise or
counterclockwise to brighten or dim
the illumination. The brightness is
linked to the adjustment of the
instrument panel light level control
while the light control switch is on.
See
Instrument Panel Illumination
Control 095.
Warning Lights and Messages
.
Engine Overheat Warning Light
. Low Coolant Warning Light
. Water Separator Warning Light
. Air Cleaner Light
. Low Fuel Warning Light
. Regeneration Warning Lights
. Exhaust System Warning Light
. Refill DEF Warning Light
. DIC Errors
. Maintenance Data
. Hour Meter
See Vehicle Messages 086.
Maintenance Data Functions
Display/Not Display the
Maintenance Data Function
Maintenance Light: On the DIC, go
to the Maintenance Indicator Light.
Switch the display by pressing and
holding the DIC selector for more
than two seconds. Turn the DIC
selector clockwise or
counterclockwise to switch the

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Instruments and Controls 87
Low Coolant Warning Light
LOW COOLANT
If this message and light come on,
the system is low on engine coolant
and the engine may overheat.
A warning tone also sounds. If this
light comes on while driving, stop
the vehicle immediately and check
the cooling system for leaks. See
Engine Coolant0231 and have the
vehicle serviced by your dealer. This
light will also activate the engine
alarm and automatic shutdown
system.
See Engine Alarm and Automatic
Shutdown 0155 andEngine
Shutdown Warning Light 080.
Water Separator (Fuel Filter)
Warning Light
WATER SEPARATOR
This message displays and a
warning light appears when the
level in the water separator on the
fuel line is beyond the specified
level. Drain water following the
instructions in the Water in Fuel section and make sure the warning
light goes out. See
Water in Fuel
0 209.
If you continue driving with the
message displayed, the fuel
injection system may fail. See Water
in Fuel 0209.
Air Cleaner Light
CHECK AIR FILTER
This message displays and a
warning light appears when the next
air cleaner element service interval
is near or has already been
reached.
Replace the air cleaner element.
See Engine Air Cleaner/Filter 0231.
Low Fuel Warning Light
LOW FUEL
This message displays and a
warning light appears when the fuel
level in the tank becomes too low
while the engine is running. Add fuel
at the earliest possible time. If the
vehicle runs out of fuel, air bleeding
procedure must be performed. See
Fuel for Diesel Engines 0206,
Fuel Gauge 072, and Running Out
of Fuel 0212.
Regeneration Required
Warning Light
REGEN. REQUIRED
This light (amber) comes on when
Running regeneration or Switch
regeneration is required. When this
light comes on, perform DPF
regeneration soon. If the engine
continues to run without performing
DPF regeneration, this light will
change color from amber to red.
If this light turns red, perform DPF
regeneration immediately. If you do
not perform DPF regeneration, the
check engine malfunction indicator
light and reduced engine power
indicator light will come on,
imposing performance restriction on
the vehicle. If this happens, the
vehicle must be serviced at your
dealer. See Diesel Particulate Filter
0 161.

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
88 Instruments and Controls
If your vehicle is equipped with a
power take-off (PTO), monitor the
DIC for DPF related indicators. PTO
and other slow speed applications
may require more attention.
Selectable (Switch)
Regeneration Required
Warning Light
SEL REGEN. REQUIRED
Performing the“Selectable”
regeneration: After the Checking PM
Level Light is shown, this light
comes on in amber when
“Selectable” regeneration is
possible. When the DPF switch is
pressed with this light ON,
"Selectable" regeneration starts.
When the selectable regeneration or
switch regeneration is interrupted:
This light (amber) comes on when
the "Selectable" regeneration or
"Switch" regeneration is interrupted.
When this light comes on, perform
DPF regeneration promptly by
following the procedure for the
"Switch" regeneration. If you
continue to operate the vehicle
without performing DPF regeneration, the color of this light
changes to red from amber. When
this light comes on in red, perform
DPF regeneration immediately by
following the procedure for the
switch regeneration. If you do not
perform DPF regeneration, the
check engine malfunction indicator
light and reduced engine power
indicator light will come on,
imposing performance restriction on
the vehicle. If this situation happens,
the vehicle must be serviced. See
Diesel Particulate Filter
0161.
If your vehicle is equipped with a
power take-off (PTO), monitor the
DIC for DPF related indicators. PTO
and other slow speed applications
may require more attention.
Regeneration in Progress
Light
REGEN. IN PROGRESS
When this light is ON, DPF
regeneration is in progress. When
the vehicle is stationary, the exhaust
sound changes as the engine speed
increases. Also, operating sounds of
the exhaust throttle may be heard. Keep people and flammable objects
away from the exhaust pipe,
because the exhaust temperature
becomes high during regeneration.
When regeneration is completed,
the light goes out automatically. See
Diesel Particulate Filter
0161.
During extended engine idling, this
light may appear on the DIC and the
DPF may be automatically
regenerated.
Checking PM Level Light
CHECKING PM LEVEL
In the case of performing the
"Selectable" regeneration, this light
comes on when the DPF switch is
kept held down. While this light is
ON, the system is checking whether
or not the "Selectable" regeneration
is possible. If the "Selectable"
regeneration is possible, the light
changes to the selectable (switch)
regeneration required warning light.
If the indication does not change to
the selectable (switch) regeneration
required warning light, the
"Selectable" regeneration is not
possible.

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Instruments and Controls 89
Exhaust System Warning Light
EXH. SYSTEM
This light comes on when the SCR
system detects a malfunction or
incorrect DEF. SCR system will turn
on other indicator lights and reduce
engine power in progressive stages
to encourage you to have the
malfunction corrected. Continuing to
drive for too long after this light
turns on will eventually result in a
severe vehicle speed limitation.
If this light turns on, promptly have
the vehicle inspected and serviced
at your dealer. SeeDiesel Exhaust
Fluid 0170.
Refill Diesel Exhaust Fluid
(DEF) Warning Light
REFILL DEF
This message displays and a
warning light appears when the DEF
tank is almost empty. Add DEF as
soon as possible.
Engine power will be reduced and
vehicle speed will be limited when
this light is activated. Failure to
promptly refill the DEF tank will result in a severe vehicle speed
limitation. See
Diesel Exhaust Fluid
0 170.
When DIC ERROR is Displayed
ERROR
If the system has not yet been able
to access maintenance data,
ERROR is shown on the DIC.
If ERROR does not change
automatically to a distance or other
maintenance indication, have your
vehicle serviced at your dealer.
Maintenance Data Indicator
Lights
Maintenance data indicator lights
appear on the DIC when each
maintenance item is selected or
when the next change or service
interval of the item is near or has
been reached.
The distance or time shown is the
remaining or excess of them to /
from the change or service timing.
The positive distance or time shows
the remaining of that and the
negative distance or time shows the
excess of that. For the items listed below, the displayed color will
change from green to amber when
remaining distance is below
1 000 km (1,000 mi) and the screen
is selected.
These screens are also displayed
when the engine control switch
turns to the ON position after above
notification timing. The message
remains on the display until the DIC
selector is pressed once or the
vehicle is started.
The maintenance data function
indicates the distance remaining
before the next scheduled
maintenance. Scheduled
maintenance time is approaching
when the display turns from green
to amber. Have the vehicle checked
and serviced at your dealer as soon
as possible.
The vehicle needs to be maintained
more often if it is driven in severe
conditions.

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Climate Controls 115
Climate Controls
Climate Control Systems
Climate Control Systems . . . . . 115
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . 118
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . 119
Service . . . . . . . . . . . . . . . . . . . . . . . 120
Climate Control
Systems
The heating, cooling, and ventilation
for the vehicle can be controlled
with this system.
Climate Control System w/Air
Conditioning shown, Heater Only similar
1. Outlet Selector Knob
2. Air Selector Lever
3. Temperature Control Knob
4. Air Conditioning (A/C) Switch, if equipped
5. Fan Speed Control Knob Outlet Selector Knob :
The Air
Selector Knob regulates air flow
from the upper, floor and defroster
outlets.
H: Air flows through the upper
outlets.
): Air flows through the upper and
floor outlets.
6: Air is flows through the floor
outlets.
-: Air flows through the floor
outlets, with some air coming from
the door window and windshield
outlets.
1: Air flows through the door
window and windshield outlets.
Air Selector Lever : The intake of
outside air and the circulation of
inside air is controlled by sliding this
lever right or left.
P: Use this position to ventilate
the interior of the cab. This position
should be normally selected.

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
120 Climate Controls
The vehicle must not be used with
the filter removed or incorrectly
installed. Failure to observe this
precaution can lead to air
conditioning system damage as a
result of dust, dirt and the like
entering the system.
Removing the Outside Air Filter
1. Remove the filter from underthe instrument panel on the
passenger side. While pressing
in the filter lock, on both sides,
pull out the filter.
2. Use a vacuum cleaner or the like to clean dust and dirt from
its surface. In order to avoid filter damage, hard
brushes should not be used for filter
cleaning.
Installing the Outside Air Filter
Install the filter in the reverse order
to removal.
Ensure that the filter is returned
securely to its original position.
Failure to observe this precaution
can lead to rattling during travel.
The vehicle must not be used with
the filter removed or incorrectly
installed. Failure to observe this
precaution can lead to air
conditioning system damage as a
result of dust, dirt, water, snow, and
the like entering the system.
Service
The air conditioning system will not
be able to cool the cab interior
effectively if the refrigerant level is
low. Accordingly, the refrigerant
level must be topped up whenever
necessary.
Please contact your dealer
whenever refrigerant must be
added. Operation Tips
Operating the air conditioning while
the refrigerant level is too low leads
not only to poor cooling
performance but also to air
conditioning system damage.
This vehicle uses the new
refrigerant HFC134a (R134a) in the
air conditioning system. No other
type of refrigerant can be used. In
order to protect the environment,
care must be taken to ensure that
refrigerant gas is never released
into open air. When refrigerant must
be replaced, therefore, please
contact your dealer or other service
facility equipped with a gas recovery
installation system.

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
126 Driving and Operating
breakdown on a highway
represents a hazard to other
vehicles and can cause an
accident. Concentrate on safe
driving. Remember to perform
daily pre-operation inspections
and use highway driving
techniques. When performing
daily pre-operation inspections,
perform the checks shown in the
table on the left with particularly
great care.
Refer toOwner Checks and
Services 0317.
. When merging with traffic on a
highway, use the turn signal
lights to indicate your intentions
ahead of time. Speed up
sufficiently when you are in the
acceleration lane. Pay attention
to vehicles behind you and to
conditions in the lane you are
joining. Merge in such a way that
you do not obstruct vehicles in
the lane.
. Your sense of how fast you are
traveling becomes distorted on
long highway drives. Constantly keep an eye on the
speedometer, and maintain a
suitable headway distance.
. During high-speed driving, even
a little turn of the steering wheel
causes a big movement of the
vehicle. Turn the steering wheel
slowly.
. Excessive use of the brake
pedal is extremely dangerous
because it rapidly wears the
brake linings and causes brake
fade. Make effective use of the
engine brake and the exhaust
brake when you want to
decelerate.
. When you want to turn off a
highway, use the turn signal
lights to indicate your intentions
ahead of time. Paying attention
to vehicles behind you, turn off
the highway smoothly so as not
to obstruct other vehicles.
Brake Fade : Frequent use of the
brakes can cause the brakes to
overheat so that the frictional force
of the brake linings decreases and the brakes become less effective
than normal. This phenomenon is
called brake fade.
Braking
Brake Operation
The brakes give strong braking
force with only light pressure on the
pedal. Do not press the brake pedal
hard except in the event of an
emergency.
Actual stopping distances vary
greatly. Your ability to stop safely
will be greatly affected by the
surface of the road, whether it is
pavement or gravel; the condition of
the road, whether it is wet, dry or
icy; tire tread; the condition of the
brakes; the weight of the vehicle;
the weight of the load; and the
amount of brake force applied.
Please allow for realistic stopping
distances to avoid unnecessary
heavy braking. That means better
braking, longer brake life and safer
driving.