GMC SIERRA 1998 Owners Manual

After the engine starts, the light should go out. If it stays
on or comes on while you are driving, you may have a
problem with your charging system. It could indicate a
problem with the generator
drive belt, or some other
charging system problem. Have it checked right away.
Driving while this light
is on could drain your battery.
If you must drive a short distance with this light on, it
helps to turn off all your accessories, such as the radio
and the
air conditioner.
Voltmeter
19
When your engine is not
running, but the ignition is
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.
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.
2-67
ProCarManuals.com

If the warning light comes on, there co11ld be a brake
problem. Have your brake system inspected right away.
This light should come on
(a) (@)
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. BRAKE
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 “Towing Your Vehicle”
in the Index.)
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.
Anti-Lock Brake System Warning Light
With the anti-lock brake
system,
this light will
come on when you start
ANTI -
LOCK
your engine and may stay
on for several seconds.
That’s normal.
2-68
ProCarManuals.com

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
“Brake System Warning Light” 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
1
This gage shows the engine
coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read
210°F (100°C) or less. If you are pulling a
load or going up hills, it is normal for the temperature to
fluctuate and approach the
260°F (1 25 “C) mark. If the
gage reaches the
260°F (125°C) mark, it indicates that
the cooling system is working beyond its capacity.
The “Problems on
the Road,” section of this manual shows
what
to do. See “Engine Overheating” in the Index.
Malfunction Indicator Lamp (Service
Engine
Soon Light) (Gasoline Engine)
SERVICE
ENGINE
SOON
Your vehicle is equipped
with a computer which
monitors operation
of the
fuel, ignition and emission
control systems.
2-69
ProCarManuals.com

This system is called OBD I1 (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the life
of the vehicle, helping to produce a cleaner
environment. The
SERVICE ENGINE SOON light
comes on to indicate that there is a problem and service
is required. Malfunctions often will be indicated by the
system before any problem is apparent. This may
prevent more serious damage to your vehicle. This
system is also designed to assist your service technician
in correctly diagnosing any malfunction.
~OTICE:
If you keep driving your vehicle with this light
on, after a while, your emission controls may not
work as well, your fuel economy may not be as
good and your engine may not run as smoothly.
This could lead to costly repairs that may not be
covered by your warranty.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is not
running. If the light doesn’t come on, have it repaired.
2-70
This light will also come on during a malfunction in one
of two ways:
0 Light Flashing -- A misfire condition has been
detected. A misfire increases vehicle emissions and
may damage the emission control system on your
vehicle. Dealer or qualified service center diagnosis
and service may be required.
0 Light On Steady -- An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis and
service may be required.
If the Light Is Flashing
The following may prevent’more serious aamage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
0 Avoiding steep uphill grades.
0 If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops flashing
and remains on steady, see “If
the Light Is On Steady” following.
If the light continues
to flash, when it is safe to do so,
stop the vehicle. Find a safe place to park your vehicle.
ProCarManuals.com

Turn the key off, wait at least 10 seconds and restart the
engine.
If the light remains on steady, see “If the Light
Is On Steady” following. If the light is still flashing,
follow the previous steps, and drive the vehicle to your
dealer or qualified service center
for service.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently
put fuel into your vehicle?
If
so, reinstall the fuel cap, making sure to fully install
the cap. The diagnostic system can determine if the fuel
cap has been left off or improperly installed.
A loose or
missing fuel cap will allow fuel to evaporate into the
atmosphere.
A few driving trips with the cap properly
installed should turn the light
off.
Did you just drive through a deep puddle of water‘?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out.
A few driving trips should turn the light off.
Are you low on fuel? As
your engine starts to run
out of fuel, your engine may
not run
as efficiently as designed since small amounts of
air are sucked into the fuel line causing
a misfire. The
system can detect this. Adding fuel should correct this
condition. Make sure to install the
fuel cap properly. It
will take
a few driving trips to turn the light off.
Have you recently changed brands of fuel?
If
so, be sure to fuel your vehicle with quality fuel (see
“Fuel”
in the Index). Poor fuel quality will cause your
engine not to run
as efficiently as designed. You may
notice this as stalling after start-up, st.alling
when you
put the vehicle into gear, misfiring, hesitation on
acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the light
to turn on.
If
you experience one or more of these conditions,
change the fuel brand
you use. It will require at least one
full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
have your dealer or qualified service center check the
vehicle. Your dealer has the proper test equipment and
diagnostic
tools to fix any mechanical or electrical
problems that may have developed.
ProCarManuals.com

Oil Pressure Gage
0
Y3
80
The oil pressure gage shows
the engine oil pressure in psi (pounds per square inch)
when the engine
is running.
Canadian vehicles indicate
pressure
in kPa (kilopascals).
Oil pressure may vary with engine speed, outside
temperature
and oil viscosity, but readings above the
low pressure zone indicate the
normal operating range.
A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem causing
low oil pressure. Check
your oil as soon as possible.
I
Don’t keep driving if the oil pressure is low. If
you do, your engine can become
so hot that it
catches fire.
You or others could be burned.
Check your oil as soon as possible and have your
vehicle serviced.
I NOTICE:
Damage to your engine from neglected oil problems
can be costly and is not covered by your warranty.
2-72
ProCarManuals.com

Security Light
SECURITY
This light will come on
briefly when you turn the
key to
START.
The light will stay on until the engme starts. If the light
flashes, the Passlock@ System has entered a tamper
mode. If the vehicle fails
to start, see “Passlock” in
the Index.
If the light comes on continuously while driving and
stays
on, there may be a problem with the Passlock
System. Your vehicle will
not be protected by Passlock,
and you should see your
GM dealer.
Up Shift Light (If Equipped)
This light is used on
some models with
manual transmissions.
The
SHIFT indicator light will help you get the best fuel
economy. See ‘(Shift Light” or ;’Shift Speeds”
in this
section for more information.
2-73
ProCarManuals.com

Daytime Running Lamps Indicator Light
:::o e..
This light goes on whenever
the
DRL are on.
Check Gages Light
CHECK
GAGES
This light will come on
briefly when you are
starting the engine.
When
it begins to get dark, the DRL indicator light is a
reminder to turn on your headlamps. If the light comes on and stays on while you are driving,
it could indicate a problem with your vehicle. It could be
a problem with your oil pressure, coolant temperature,
or
some other problem. Check your various gages to see
if they are in the warning zones. If they are, have your
vehicle serviced right away.
2-74
ProCarManuals.com

Fuel Gage
The fuel gage, when the
ignition is on, tells you
about how much fuel you
have left
in your tank.
The
gage will first indicate EMPTY (E) before you
are out of fuel, and you should get more fuel as soon
as possible. Here
are four situations you may experience with your
fuel gage. None of these indicate a problem with the
fuel gage.
At the gas station, the fuel pump shuts off before the
gage reads FULL
(F).
It takes a little more or less fuel to fill up than the
fuel gage indicated. For example, the gage may have
indicated the tank was half
full, but it actually took a
little more or less than half the tank’s capacity to
fill
the tank.
The gage moves a little when you turn a corner or
speed up.
The gage doesn’t go back to EMPTY (E) when you
turn off’ the ignition.
If you have a diesel engine, see “Fuel Gage” in the
Diesel Engine Supplement.
2-75
ProCarManuals.com

2-76
ProCarManuals.com