check engine light GMC SONOMA 1999 Owner's Manual

2-12
Passlock
Your vehicle is equipped with the Passlock
theft
-deterrent system.
Passlock is a passive theft
-deterrent system. Passlock
enables fuel if the ignition lock cylinder is turned with a
valid key. If a correct key is not used or the ignition lock
cylinder is tampered with, fuel is disabled.
During normal operation, the will go off approximately
five seconds after the key is turned to the
RUN ignition position.
If the engine stalls and the SECURITY light flashes,
wait about 10 minutes until the light stops flashing
before trying to restart the engine. Remember to release
the key from START as soon as the engine starts.
If the engine does not start after three (3) tries, the
vehicle needs service.
If the engine is running and the SECURITY light comes
on, you will be able to restart the engine if you turn the
engine off. However, your Passlock system is not working
properly and must be serviced by your dealer. Your vehicle
is not protected by Passlock at this time. You may also
want to check the fuse (see ªFuses and Circuit Breakersº
in the Index). See your dealer for service.
In an emergency, call the GM Roadside Assistance
Center. See ªRoadside Assistanceº in the Index.
New Vehicle ªBreak-Inº
NOTICE:
Your vehicle doesn't need an elaborate
ªbreak
-in.º But it will perform better in the long
run if you follow these guidelines:

Keep your speed at 55 mph (88 km/h) or
less for the first 500 miles (805 km).

Don't drive at any one speed
-- fast or
slow
-- for the first 500 miles (805 km).
Don't make full
-throttle starts.

Avoid making hard stops for the first
200 miles (322 km) or so. During this time
your new brake linings aren't yet broken
in. Hard stops with new linings can mean
premature wear and earlier replacement.
Follow this breaking
-in guideline every
time you get new brake linings.

Don't tow a trailer during break
-in.
See ªTowing a Trailerº in the Index for
more information.

2-54
NOTICE:
Do not operate the engine with the tachometer in
the red range, or engine damage will occur.
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 tone
nor the light will come on.

2-57
CAUTION:
If the air bag readiness light ever comes on when
you have turned off the air bag, it means that
something may be wrong with the air bag system.
The right front passenger's air bag could inflate
even though the switch is off. If this ever
happens, don't let anyone whom the national
government has identified as a member of a
passenger air bag risk group sit in the right front
passenger's position (for example, don't secure a
rear
-facing child restraint in your vehicle) until
you have your vehicle serviced.
Charging System Indicator Light
The charging system light
will come on briefly when
you turn on the ignition, but
the engine is not running, as
a check to show you it
is working.
It should go out once the engine is running. If it stays
on, or comes on while you are driving, you may have a
problem with the charging system. It could indicate that
you have problems with a generator drive belt, or
another electrical problem. Have it checked right away.
Driving while this light is on could drain your battery.
If you must drive a short distance with the light on, be
certain to turn off all your accessories, such as the radio
and air conditioner.

2-62
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.
This light will also come on during a malfunction in one
of two ways:

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.

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 damage to
your vehicle:

Reducing vehicle speed.

Avoiding hard accelerations.

Avoiding steep uphill grades.

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
ªIf the Light Is On Steadyº 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.
Turn the key off, wait at least 10 seconds and restart the
engine. If the light remains on steady, see ªIf the Light
Is On Steadyº 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. See ªFilling Your Tankº in the Index. 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.

2-63
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel
(see ªFuelº 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, stalling
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.Emissions Inspection and Maintenance Programs
Some state/provincial and local governments have or may
begin programs to inspect the emission control equipment
on your vehicle. Failure to pass this inspection could
prevent you from getting a vehicle registration.
Here are some things you need to know in order to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the SERVICE
ENGINE SOON light is on or not working properly.
Your vehicle will not pass this inspection if the OBD
(on
-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen if
you have recently replaced your battery or if your
battery has run down. The diagnostic system is designed
to evaluate critical emission control systems during
normal driving. This may take several days of routine
driving. If you have done this and your vehicle still does
not pass the inspection for lack of OBD system
readiness, see your dealer or qualified service center to
prepare the vehicle for inspection.

2-65 Security Warning Light
This light will come on
briefly when you turn the
key toward START. The
light will stay on until the
engine starts.
If the light flashes, the Passlock

system has entered a
tamper mode. If the vehicle fails to start, see ªPasslockº
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 dealer.
Also see ªContent Theft
-Deterrentº in the Index for
additional information regarding the SECURITY light.
Service Four-Wheel-Drive Warning Light
If your vehicle is equipped with the Automatic
Four
-Wheel-Drive Transfer Case, it has a computer
which controls the four
-wheel-drive system.
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.

2-66 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.
Fuel Gage
When the ignition is on, the
fuel gage tells you about
how much fuel you
have remaining.Here are four things that some owners ask about.
None of these show a problem with your fuel gage:

At the gas station, the gas pump shuts off before the
gage reads F (Full).

It takes a little more or less fuel to fill up than the 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 E (Empty) when you
turn off the ignition.
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.

4-7
Avoid needless heavy braking. Some people drive in
spurts
-- heavy acceleration followed by heavy
braking
-- rather than keeping pace with traffic. This is a
mistake. Your brakes may not have time to cool between
hard stops. Your brakes will wear out much faster if you
do a lot of heavy braking. If you keep pace with the
traffic and allow realistic following distances, you will
eliminate a lot of unnecessary braking. That means
better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do, the
pedal may get harder to push down. If your engine
stops, you will still have some power brake assist. But
you will use it when you brake. Once the power assist is
used up, it may take longer to stop and the brake pedal
will be harder to push.
Anti-Lock Brakes (ABS)
Your vehicle has anti-lock brakes (ABS). ABS is an
advanced electronic braking system that will help
prevent a braking skid.
When you start your engine and begin to drive away,
your anti
-lock brake system will check itself. You may
hear a momentary motor or clicking noise while this test
is going on. This is normal.
If there's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº in
the Index.

4-39
CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will help
keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well
-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlamps. Let the heater run for a while.Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
Recreational Vehicle Towing
Your vehicle should not be towed with all four wheels
on the ground. Your transmission has no provision for
internal lubrication while being towed. To properly tow
your vehicle, it should be placed on a platform trailer
with all four wheels off the ground. Towing with all four
wheels on the ground should be avoided.
In rare cases when it's unavoidable and your vehicle must
be towed with all four wheels on the ground, the propeller
shaft to axle yoke orientation should be marked and the
propeller shaft removed following the applicable service
manual removal/installation procedure. See ªService and
Owner Publicationsº in the Index.