2020 CHEVROLET LOW CAB FORWARD warning

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
186 Driving and Operating
Diesel Exhaust Fluid (DEF) Low
Level Warning
Diesel Exhaust Fluid (DEF) is a
required fluid for the operation of
your diesel engine just as diesel fuel
is required. To avoid running out of
DEF your vehicle will turn on
warning and indicator lights and
reduce engine power in progressive
stages to encourage adding DEF.
The following is a summary of the
diesel exhaust fluid (DEF) low level
warning lights, indicator lights and
engine power reductions.
Continuing to drive for too long after
these lights come on will eventually
result in a severe vehicle speed
limitation.These warning and indicator lights
will go out automatically and engine
power will be restored to normal
after the SCR system detects that
the DEF tank is refilled with DEF.

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
188 Driving and Operating
DEF Tank Level is Low/Empty (cont'd)
StageStage 1 Stage 2Stage 3Stage 4
Indicator light(s)
SolidSlow blinkingFast blinkingFast blinking
Warning buzzer 1 short beep 3 short beeps *3 3 quick beeps *4 Continuous beeping
Restrictions Vehicle speed is
limited to
89 km/h (55 MPH) Vehicle speed is
limited to
56 km/h (35 MPH)Vehicle speed is
limited to
56 km/h (35 MPH)Vehicle speed is
limited to
8 km/h (5 MPH)
Required action Refill DEF as soon
as possible *1 Refill DEF tank
immediately *1Refill DEF tank
immediately *1Refill DEF tank
immediately *1

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.

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 191
Incorrect DEF/SCR System Malfunction (Type A) Warnings
Stage Stage 1Stage 2Stage 3Stage 4
DIC main display
DEF gauge (DIC sub
display 2) Various Various Various Various
Indicator light(s)
Slow blinkingFast blinkingFast blinking

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
192 Driving and Operating
Incorrect DEF/SCR System Malfunction (Type A) Warnings (cont'd)
Stage Stage 1Stage 2Stage 3Stage 4
Indicator light(s)
orororor
Warning buzzer 1 short beep 3 short beeps *1 3 quick beeps *2 Continuous beeping
Restriction Vehicle speed:
89 km/h (55 MPH) Vehicle speed:
56 km/h (35 MPH)Vehicle speed:
56 km/h (35 MPH)Vehicle speed:
8 km/h (5 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 193
Remarks:
*1–The warning buzzer continues
to sound every 5 minutes.
*2 –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.
When the exhaust system warning
light comes on DIC, promptly have
the vehicle inspected and serviced
at a dealer.
Stage 1 : When incorrect DEF or an
SCR system malfunction (Type A) is
detected, the 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 for
another approximately
160 km (100 miles), the 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 for
approximately
105 more km (65 miles), 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
further on (approximately
8 km (5 miles)) or when the engine
is restarted.
Stage 4 : DEF indicator light is
blinking quickly, the other warning
lights are on and the buzzer is
beeping continuously indicates the
vehicle speed is limited to 8 km/h (5
MPH). See Vehicle Messages 074,
Malfunction Indicator Lamp (Check
Engine Light) 061, Diesel Exhaust
Fluid (DEF) Warning Light 068, and
Reduced Engine Power Light 069.

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
194 Driving and Operating
SCR System Malfunction (Type B) Warning
StageStage 1
Trigger SCR system malfunction detected
DIC main display
DEF gauge (DIC sub
display 2) Various