2024 GMC SIERRA service

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
120 Instruments and Controls
correct itself as higher engine speeds allow
the charging system to create maximum
power.
The vehicle can only be driven for a short
time with the readings outside the normal
operating range. If the vehicle must be
driven, turn off all accessories, such as the
radio and air conditioner.
Readings outside the normal operating
range indicate a possible problem in the
electrical system. Have the vehicle serviced
as soon as possible.
Uplevel
This gauge displays while the lower gauges
are configured to display four gauges. When
the vehicle is in the Tow/Haul driver mode
this gauge is replaced by the transmission
temperature gauge. To change gauge
configurations, see“Options”under
Instrument Cluster (Base Level) 0112 or
Instrument Cluster (Uplevel) 0113.
Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a driver seat belt reminder light on
the instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to remind
the driver to fasten their seat belt. Then the
light stays on solid until the belt is buckled.
This cycle may continue several times if the
driver remains or becomes unbuckled while
the vehicle is moving.
If the driver seat belt is buckled, neither the
light nor the chime comes on.
Front Passenger Seat Belt Reminder
Light
The vehicle may have a front passenger seat
belt reminder light near the passenger
airbag status indicator.
See Passenger Sensing System 069.
When the vehicle is started, this light
flashes and a chime may come on to remind
passengers to fasten their seat belt. Then
the light stays on solid until the belt is
buckled. This cycle continues several times if
the front passenger remains or becomes
unbuckled while the vehicle is moving.
If the front passenger seat belt is buckled,
neither the chime nor the light comes on.
The front passenger seat belt reminder light
and chime may turn on if an object is put
on the seat such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device. To turn off the reminder light and/or
chime, remove the object from the seat or
buckle the seat belt.
Second Row Passenger Seat Belt
Reminder Lights
The vehicle may have second row passenger
seat belt reminder lights.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
Instruments and Controls 121
When the vehicle is started, these lights
come on solid to remind rear passengers to
fasten their seat belts. Then each light may
stay on solid or flash, and a chime may
come on if the rear passenger remains
unbuckled, or becomes unbuckled, when the
vehicle is moving. An X indicates the seat
belt is not buckled. A check mark indicates
the seat belt is buckled.
If all rear seat positions are buckled, neither
the chime nor the lights will come on.
For information on the front seat belt
reminder lights, see "Driver Seat Belt
Reminder Light" and "Front Passenger Seat
Belt Reminder Light" listed previously.
Airbag Readiness Light
This light shows if there is an electrical
problem with the airbag system. It is
located in the instrument cluster. The
system check includes the airbag sensor(s),
the passenger sensing system, the
pretensioners, the airbag modules, the
wiring, and the crash sensing and diagnostic
module. For more information on the airbag
system, seeAirbag System 064.
The airbag readiness light comes on for
several seconds when the vehicle is started.
If the light does not come on then, have it
fixed immediately.
{Warning
If the airbag readiness light stays on
after the vehicle is started or comes on
while driving, it means the airbag system
might not be working properly. The
airbags in the vehicle might not inflate in
a crash, or they could even inflate
without a crash. To help avoid injury,
have the vehicle serviced right away.
If there is a problem with the airbag
system, a Driver Information Center (DIC)
message may also come on.
Passenger Airbag Status Indicator
The vehicle has a passenger sensing system.
See Passenger Sensing System 069 for
important safety information. The overhead
console has a passenger airbag status
indicator.
United States
Canada
When the vehicle is started, the passenger
airbag status indicator will light ON and OFF,
or the symbols for on and off, for several
seconds as a system check. Then, after
several more seconds, the status indicator

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
122 Instruments and Controls
will light either ON or OFF, or either the on
or off symbol, to let you know the status of
the front outboard passenger frontal airbag.
If the word ON or the on symbol is lit on
the passenger airbag status indicator, it
means that the front outboard passenger
frontal airbag is allowed to inflate.
If the word OFF or the off symbol is lit on
the passenger airbag status indicator, it
means that the passenger sensing system
has turned off the front outboard passenger
frontal airbag.
If, after several seconds, both status
indicator lights remain on, or if there are no
lights at all, or if the airbag readiness light
is on, there may be a problem with the
lights or the passenger sensing system. See
your dealer for service right away.
{Warning
If the airbag readiness light ever comes
on and stays on, it means that
something may be wrong with the airbag
system. To help avoid injury to yourself
or others, have the vehicle serviced right(Continued)
Warning (Continued)
away. SeeAirbag Readiness Light 0121
for more information, including important
safety information.
Charging System Light
The charging system 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. Have it checked
by your dealer. Driving while this light is on
could drain the battery.
When this light comes on, or is flashing, the
Driver Information Center (DIC) also displays
a message. If a short distance must be driven with the
light on, be sure to turn off all accessories,
such as the radio and air conditioner. Find a
safe place to stop the vehicle.
Malfunction Indicator Lamp
(Check Engine Light)
This light is part of the vehicle’s emission
control on-board diagnostic system. If this
light is on while the engine is running, a
malfunction has been detected and the
vehicle may require service. The light should
come on to show that it is working when
the ignition is on and the engine is not
running. See
Ignition Positions 0216.
Malfunctions are often indicated by the
system before any problem is noticeable.
Being aware of the light and seeking service
promptly when it comes on may prevent
damage.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
Instruments and Controls 123
Caution
If the vehicle is driven continually with
this light on, the emission control system
may not work as well, the fuel economy
may be lower, and the vehicle may not
run smoothly. This could lead to costly
repairs that might not be covered by the
vehicle warranty.
Caution
Modifications to the engine, transmission,
exhaust, intake, or fuel system, or the
use of replacement tires that do not
meet the original tire specifications, can
cause this light to come on. This could
lead to costly repairs not covered by the
vehicle warranty. This could also affect
the vehicle’s ability to pass an Emissions
Inspection/Maintenance test. See
Accessories and Modifications0310.
If the light is flashing : A malfunction has
been detected that could damage the
emission control system and increase vehicle
emissions. Diagnosis and service may be
required. To help prevent damage, reduce vehicle
speed and avoid hard accelerations and
uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as soon as
possible.
If the light continues to flash, find a safe
place to park. Turn the vehicle off and wait
at least 10 seconds before restarting the
engine. If the light is still flashing, follow
the previous guidelines and see your dealer
for service as soon as possible.
If the light is on steady :
A malfunction has
been detected. Diagnosis and service may be
required.
Check the following:
.If fuel has been added to the vehicle
using the capless funnel adapter, make
sure that it has been removed. See
“Filling the Tank with a Portable Gas Can”
under Filling the Tank (Chassis Cab and
Box Delete Models) 0275 or
Filling the Tank (Pickup Models) 0273.
The diagnostic system can detect if the
adapter has been left installed in the
vehicle, allowing fuel to evaporate into
the atmosphere. A few driving trips with
the adapter removed may turn off the
light.
.Poor fuel quality can cause inefficient
engine operation and poor driveability,
which may go away once the engine is
warmed up. If this occurs, change the fuel
brand. It may require at least one full
tank of the proper fuel to turn the light
off. See Recommended Fuel 0272.
If the light remains on, see your dealer.
Emissions Inspection and Maintenance
Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).
The DLC is under the instrument panel to
the left of the steering wheel. Connecting
devices that are not used to perform an
Emissions Inspection/Maintenance test or to
service the vehicle may affect vehicle

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
124 Instruments and Controls
operation. SeeAdd-On Electrical Equipment
0 306. See your dealer if assistance is
needed.
The vehicle may not pass inspection if:
.The light is on when the engine is
running.
.The light does not come on when the
ignition is on while the engine is off.
.Critical emission control systems have not
been completely diagnosed. If this
happens, the vehicle would not be ready
for inspection and might require
several days of routine driving before the
system is ready for inspection. This can
happen if the 12-volt battery has recently
been replaced or run down, or if the
vehicle has been recently serviced.
See your dealer if the vehicle will not pass
or cannot be made ready for the test.
Brake System Warning Light
MetricEnglish This light comes on briefly when the vehicle
is turned on to show that the light is
working. If it does not come on then, have
it fixed so it will be ready to warn you if
there is a problem.
If the light comes on and stays on, there is
a brake problem. Have the brake system
inspected right away. This light may come
on if the brake fluid is low. See
Brake Fluid
0 326.
If the light comes on while driving, pull off
the road and stop carefully. The brake pedal
might be harder to push, or the brake pedal
may go closer to the floor. It could take
longer to stop. If the light is still on, have
the vehicle towed for service. See
Transporting a Disabled Vehicle 0379.
{Warning
The brake system might not be working
properly if the brake system warning
light is on. Driving with the brake system
warning light on can lead to a crash.
If the light is still on after the vehicle has
been pulled off the road and carefully
stopped, have the vehicle towed for
service.
Electric Parking Brake Light
MetricEnglish
This light comes on when the parking brake
is applied. If the light continues flashing
after the parking brake is released, or while
driving, there is a problem with the Electric
Parking Brake system. A message may also
display in the Driver Information
Center (DIC).
If the light does not come on, or remains
flashing, see your dealer.
Service Electric Parking Brake
Light

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
Instruments and Controls 125
This light may come on briefly when the
vehicle is turned on. If it does not come on,
have it fixed so it will be ready to warn if
there is a problem.
If this light stays on or comes on while
driving, there is a problem with the Electric
Parking Brake (EPB). Take the vehicle to a
dealer as soon as possible. In addition to the
parking brake, other safety functions that
utilize the EPB may also be degraded.
A message may also display in the Driver
Information Center (DIC). SeeElectric Parking
Brake 0234.
Antilock Brake System (ABS)
Warning Light
This light comes on briefly when the vehicle
is turned on to show that the light is
working. If it does not come on then, have
it fixed so it will be ready to warn you if
there is a problem. Engagement of the 4WD front axle lock will
disable ABS and illuminate the ABS warning
light. The ABS warning light will turn off
when the front axle lock is disengaged.
If the ABS warning light stays on, or comes
on again while driving, the vehicle needs
service. A chime may also sound when the
light stays on.
If the ABS warning light is the only light on,
the vehicle has regular brakes, but ABS is
not functioning.
If both the ABS warning light and the brake
system warning light are on, ABS is not
functioning and there is a problem with the
regular brakes. See your dealer for service.
See
Brake System Warning Light 0124.
Four-Wheel-Drive Light
Auto Mode Shown, Other Modes Similar If equipped, the four-wheel-drive light
displays what mode the vehicle is in. The
light will show each mode: 2WD, 4HI, AUTO
(all transfer cases); 4LOW and N (two-speed
transfer case only).
The light will flash when a shift is in
progress. Once the shift is complete the
light will be steady.
If the light turns amber, there may be a
malfunction with the four-wheel-drive
system. See your dealer.
See
Four-Wheel Drive 0228.
Tow/Haul Mode Light
For vehicles with the Tow/Haul Mode
feature, this light comes on when the Tow/
Haul Mode has been activated.
See Tow/Haul Mode 0227.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
128 Instruments and Controls
This light comes on when the Electronic
Stability Control (ESC) system is turned off.
If ESC is off, the Traction Control System
(TCS) is also off. To turn ESC off and on, see
Traction Control/Electronic Stability Control
0236.
If ESC and TCS are off, the systems do not
assist in controlling the vehicle. Adjust
driving accordingly.
Engine Coolant Temperature
Warning Light
This light comes on briefly while starting
the vehicle.
If it does not, have the vehicle serviced by
your dealer. If the system is working
normally the indicator light goes off.
Caution
The engine coolant temperature warning
light indicates that the vehicle has
overheated. Driving with this light on can
damage the engine and it may not be
covered by the vehicle warranty. See
Engine Overheating 0321.
The engine coolant temperature warning
light comes on when the engine has
overheated.
If this happens, pull over and let the engine
idle. See Engine Overheating 0321.
Driver Mode Control Light
This light comes on when Normal Mode is
selected.
This light comes on when Snow Mode is
selected.
This light comes on when Off-Road Mode is
selected.
See Driver Mode Control 0238.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/15/22
Instruments and Controls 129
Tire Pressure Light
If equipped with the Tire Pressure Monitor
System (TPMS), this light comes on briefly
when the vehicle is started. It provides
information about tire pressures and
the TPMS.
When the Light Is On Steady
This indicates that one or more of the tires
are significantly underinflated.
A Driver Information Center (DIC) tire
pressure message may also display. Stop as
soon as possible, and inflate the tires to the
pressure value shown on the Tire and
Loading Information label. SeeTire Pressure
0 350.
When the Light Flashes First and Then Is On
Steady
If the light flashes for about a minute and
then stays on, there may be a problem with
the TPMS. If the problem is not corrected, the light will come on every time the
vehicle is started. See
Tire Pressure Monitor
Operation 0351.
Engine Oil Pressure Light (Uplevel
Cluster)
Caution
Driving the vehicle with low engine oil
pressure can damage the engine and the
repairs would not be covered by the
vehicle warranty.
If the engine oil pressure light comes on
while driving:
1. Stop in a safe location and turn off the engine.
2. Check the oil level. See Engine Oil
0 314.
3. Add oil if the oil level is below the normal operating range.
4. Restart the vehicle. If the engine oil pressure light stays on for more
than 10 seconds, turn the vehicle
back off. Do not restart the vehicle.
See your dealer for service.
This light should come on briefly when the
engine starts. When the engine is off and
the vehicle is on, the light should remain
illuminated. If it does not come on under
either condition, contact your dealer.
If the light comes on and stays on when the
engine is running, it may not have adequate
oil pressure. The oil level may be low or
there may be some other oil system
problem. Turn the engine off when it is safe
to do so and contact your dealer.
Low Fuel Warning Light
A Low Fuel Warning Light near the fuel
gauge comes on briefly when the ignition is
turned on as a check to show it is working.