2002 GMC SONOMA warning light

iv
Vehicle Damage Warnings
Also, in this book you will find these notices:
NOTICE:
These mean there is something that could damage
your vehicle.
In the notice area, we tell you about something that can
damage your vehicle. Many times, this damage would
not be covered by your warranty, and it could be costly.
But the notice will tell you what to do to help avoid
the damage.
When you read other manuals, you might see
CAUTION and NOTICE warnings in different
colors or in different words.
You'll also see warning labels on your vehicle.
They use the same words, CAUTION or NOTICE.
Vehicle Symbols
Your vehicle may be equipped with components and
labels that use symbols instead of text. Symbols,
used on your vehicle, are shown along with the text
describing the operation or information relating to a
specific component, control, message, gage or indicator.
If you need help figuring out a specific name of a
component, gage or indicator reference the following
topics in the Index:

ªEngine Compartment Overviewº

ªInstrument Panelº

ªComfort Controlsº

ªAudio Systemsº
Also see ªWarning Lights and Gagesº in the Index.

2-34
Parking Brake
The parking brake is located near the bottom of the
instrument panel on the driver's side.
To set the parking brake, hold the regular brake pedal
down with your right foot. Push down the parking brake
pedal with your left foot. If the ignition is on, the brake
system warning light will come on.
NOTICE:
Driving with the parking brake on can cause
your rear brakes to overheat. You may have to
replace them, and you could also damage other
parts of your vehicle.
To release the parking brake hold the regular brake
pedal down.
If you are towing a trailer and you must park on a hill,
see ªTowing a Trailerº in the Index. That section shows
what to do first to keep the trailer from moving.

2-69
Warning Lights, Gages and
Indicators
This part describes the warning lights and gages that
may be on your vehicle. The pictures will help you
locate them.
Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause an
expensive repair or replacement. Paying attention to
your warning lights and gages could also save you or
others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle's functions. As you
will see in the details on the next few pages, some
warning lights come on briefly when you start the
engine just to let you know they're working. If you are
familiar with this section, you should not be alarmed
when this happens.
Gages can indicate when there may be or is a problem
with one of your vehicle's functions. Often gages and
warning lights work together to let you know when
there's a problem with your vehicle.When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual's advice.
Waiting to do repairs can be costly
-- and even
dangerous. So please get to know your warning lights
and gages. They're a big help.
Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
come on for about eight seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light
will also come on and stay
on for about 20 seconds,
then it will flash for about
55 seconds.
If the driver's belt is already buckled, neither the chime
nor the light will come on.

2-73 Voltmeter Gage
When your engine is not
running, but the ignition is
on (in RUN), this gage
shows your battery's state of
charge in DC volts.
When the engine is running, the gage shows the
condition of the charging system. Readings between the
low and high warning zones indicate the normal
operating range.
Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power at
engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.You can only drive for a short time with the reading in
either warning zone. If you must drive, turn off all
unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Shift Light
You have the shift light if
you have a manual
transmission.
Shifting when the indicator light is on will help you get
the best fuel economy. See ªShift Lightº in the Index.

2-74 Brake System Warning Light
When the ignition is on, the brake system warning light
will come on when you set your parking brake. The light
will stay on if your parking brake doesn't release fully.
If it stays on after your parking brake is fully released, it
means you have a brake problem.
Your vehicle's hydraulic brake system is divided into
two parts. If one part isn't working, the other part can
still work and stop you. For good braking, though, you
need both parts working well.
If the warning light comes on, there could be a brake
problem. Have your brake system inspected right away.
United States CanadaThis light should come on briefly when you turn the
ignition key to RUN. If it doesn't come on then, have
it fixed so it will be ready to warn you if there's a
problem.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the floor.
It may take longer to stop. If the light is still on, have the
vehicle towed for service. See ªTowing Your Vehicleº in
the Index.
CAUTION:
Your brake system may not be working properly
if the brake system warning light is on. Driving
with the brake system warning light on can lead
to an accident. If the light is still on after you've
pulled off the road and stopped carefully, have
the vehicle towed for service.

2-75 Anti-Lock Brake System Warning Light
With the anti-lock brake
system, this light will come
on when you start your
engine and may stay on
for several seconds.
That's normal.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the regular brake system
warning light isn't on, you still have brakes, but you
don't have anti
-lock brakes. If the regular brake system
warning light is also on, you don't have anti
-lock brakes
and there's a problem with your regular brakes. See
ªBrake System Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
Engine Coolant Temperature Gage
United States Canada
This gage shows the engine coolant temperature. If the
gage pointer moves into the red area, your engine is
too hot!
It means that your engine coolant has overheated. If you
have been operating your vehicle under normal driving
conditions, you should pull off the road, stop your
vehicle and turn off the engine as soon as possible. See
ªEngine Overheatingº in the Index.

2-81 Service Four-Wheel-Drive Warning Light
This light should come on
briefly when you turn on the
ignition, as a check to show
you it is working.
The SERVICE 4WD light comes on to indicate that
there may be a problem with the four
-wheel drive
system and service is required. Malfunctions can be
indicated by the system before any problem is apparent,
which may prevent serious damage to the vehicle. This
system is also designed to assist your service technician
in correctly diagnosing a malfunction.
Check Gages Light
If this light comes on and
stays on while you are
driving, check your coolant
temperature and engine oil
pressure gages to see if they
are in the warning zones.

2-83 Low Fuel Light
This light comes on briefly
when you start your engine.
This light comes on when the fuel tank is low on fuel.
To turn it off, add fuel to the fuel tank. See ªFuelº in
the Index.
Driver Information Center (DIC) (If Equipped)
This system displays the outside air temperature,
compass direction and trip information in the
overhead console.
US/MET (United States/Metric): The US/MET
(United States/metric) button allows you to switch the
display between the English and metric system.
MODE: The MODE button can be used to toggle
between three modes of operation: OFF, COMP/TEMP
and TRIP.COMP/TEMP (Compass/Temperature): The
display provides the outside temperature and one of
eight compass readings to indicate the direction the
vehicle is facing.
Before you turn on the ignition and move the vehicle,
the temperature indicated will be the last outside
temperature recorded with the ignition on. If the outside
temperature is 37
F (3
C) or lower, the display will
toggle between the word ICE and the current
temperature every eight seconds. This is a warning to
the driver that road conditions may be icy, and that
appropriate precautions should be taken.
The compass is self
-calibrating, so it does not need to be
manually set. However, if ªCº (Calibration) is
displayed, the compass will need to be calibrated. You
may also place the compass in a noncalibrated mode by
pressing and holding the MODE and US/MET buttons
simultaneously while in the COMP/TEMP mode. After
about 10 seconds, the compass will display C and you
can release the buttons. Drive the vehicle in a complete
360
circle three times at a speed of less than 5 mph
(8 km/h), and the compass will function normally. Once
the calibration is complete, the display will return to a
compass reading.