service indicator CHEVROLET LOW CAB FORWARD 2020 Owner's 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
52 Instruments and Controls
Instruments and
Controls
Controls
Steering Wheel Adjustment . . . . 53
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Windshield Wiper/Washer . . . . . . 54
Power Outlets . . . . . . . . . . . . . . . . . 55
Warning Lights, Gauges, and
Indicators
Warning Lights, Gauges, andIndicators . . . . . . . . . . . . . . . . . . . . 56
Instrument Cluster . . . . . . . . . . . . . 57
Speedometer . . . . . . . . . . . . . . . . . . 58
Odometer . . . . . . . . . . . . . . . . . . . . . . 58
Trip Odometer . . . . . . . . . . . . . . . . . 58
Tachometer . . . . . . . . . . . . . . . . . . . . 59
Fuel Gauge . . . . . . . . . . . . . . . . . . . . 59
Engine Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . . . 60
Diesel Exhaust Fluid (DEF) Gauge . . . . . . . . . . . . . . . . . . . . . . . . 60
Seat Belt Reminders . . . . . . . . . . . 60
Battery Warning Light . . . . . . . . . . 61
Malfunction Indicator Lamp (Check Engine Light) . . . . . . . . . 61
Service Vehicle Soon Light . . . . 62 Brake System Warning Light
(Parking Brake Light) . . . . . . . . . 62
Antilock Brake System (ABS) Warning Light . . . . . . . . . . . . . . . . 64
Exhaust Brake Light . . . . . . . . . . . 65
Service Transmission Warning
Light . . . . . . . . . . . . . . . . . . . . . . . . . 65
Automatic Transmission Fluid Temperature Warning Light . . . 66
Overdrive Off Light . . . . . . . . . . . . . 66
Wait-to-Start Light . . . . . . . . . . . . . 67
Engine Oil Pressure Light . . . . . . 67
Engine Oil Level Indicator Light . . . . . . . . . . . . . . . . . . . . . . . . . 67
Diesel Exhaust Fluid (DEF) Warning Light . . . . . . . . . . . . . . . . 68
Engine Shutdown Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . 68
Idle Shutdown Light . . . . . . . . . . . . 68
Reduced Engine Power Light . . . . . . . . . . . . . . . . . . . . . . . . . 69
High-Beam On Light . . . . . . . . . . . 69
Daytime Running Lamps (DRL) Indicator Light . . . . . . . . . . . . . . . . 69
Cruise Control Light . . . . . . . . . . . 70
Information Displays
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . 70
Vehicle Messages
Vehicle Messages . . . . . . . . . . . . . 74
Warning Buzzers . . . . . . . . . . . . . . 79

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
Instruments and Controls 61
This warning light comes on and a
warning buzzer sounds when the
driver is not wearing the seat belt
while the engine control switch is in
the ON position.
When the vehicle speed exceeds
20 km/h (12 mph) with the seat belt
unbuckled, the warning light will
flash and the buzzer will continue to
sound. The warning light will go out
and the warning buzzer will stop
when the driver buckles the
seat belt.
Battery Warning Light
This light comes on briefly when the
ignition is turned on, but the engine
is not running, as a check to show
the light is working. It should go out
when the engine is started.
If the light stays on, or comes on
while driving, there may be a
problem with the electrical charging
system (such as a loose or broken
fan belt). Pull off to a safe place well
clear of traffic and contact your
dealer. Driving while this light is on
could drain the battery.
Check and Corrective Action1. Check to see if the fan belt is broken or loose.
2. If the fan belt is loose, adjust the tension.
3. If the fan belt is broken or there is no abnormality in the fan
belt, see your dealer for
service.
See Battery - North America 0259,
Jump Starting - North America
0 301, and Engine Drive Belt
Routing 0355.Malfunction Indicator
Lamp (Check Engine
Light)
This light should come on to show
that it is working when the engine
control switch is turned to the ON
position, and then should go out
after the engine is started.
If this light stays on or comes on
while the engine is running, it
indicates a malfunction with the
engine electronic emission control
system. Avoid driving at high
speeds and have the vehicle
inspected by your dealer.
If this light comes on when the fuel
tank is empty, you do not need to
have your vehicle serviced. See
Running Out of Fuel 0224.

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
72 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 083.
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 074.
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 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Instruments and Controls 75
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 Coolant0243 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 0164 and
Engine Shutdown Warning Light
0 68.
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
0 221.
If you continue driving with the
message displayed, the fuel
injection system may fail. See Water
in Fuel 0221.
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 0243.
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 0218,
Fuel Gauge 059, and Running Out
of Fuel 0224.
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
0 171.

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
76 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
0171.
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
0171.
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 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Instruments and Controls 77
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 0180.
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
0 180.
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
1 600 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 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 165
If the idling stop function does not
initiate, a transmission related
problem may have occurred. Please
contact your dealer. (There is a
Diagnostic Trouble Code (DTC) that
inhibits the idling stop function when
the Service Transmission Warning
Light is not illuminated).
High Idle System
Use high idle mode to increase
engine idle speed to 1,200 r/min
when the vehicle is stationary.
Activating High Idle Mode
Follow the below procedure to
activate the high idle mode:1. Set the parking brake.
2. Set the selector lever in P (Park) or N (Neutral) position.
3. Do not press the brake pedal. 4. Press the cruise control main
switch to set it to ON. At this
time, the operation indicating
light will turn to green.
5. Turn and hold the cruise control set switch in the SET
position. After approximately
3 seconds the cruise control
set indicator light will begin to
flash slowly and the engine idle
will increase to 1,200 r/min.
Canceling High Idle Mode
Any of the following actions will
cancel high idle mode.
. The cruise control main switch is
set to OFF.
. The brake pedal is pressed.
. The parking brake is released.
. The selector lever is moved from
P (Park) or N (Neutral) position.
. The accelerator pedal is
pressed, accelerating the engine
beyond the engine speed
threshold.

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
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.