check engine GMC C-SERIES 1999 User Guide

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2-62 Low Coolant Warning Light
You have a LOW
COOLANT warning light.
If this light comes on,
your system is low on
coolant and the engine
may overheat.
The warning light should come on briefly, as a check,
when you turn on the ignition.
When it comes on, you will also hear a warning tone at
five beats per second for 10 seconds. See ªEngine
Coolantº in the Index and have your vehicle serviced as
soon as you can.
This light may also come on if your vehicle is equipped
with the optional automatic engine shutdown system and
engine shutdown has begun. SeeªEngine Automatic
Shutdownº in the Index.
Manual Fast Idle Indicator Light
(If Equipped)
If your vehicle is equipped
with an electronically
controlled diesel engine or
gasoline engine, you may
have this indicator light. It
is located next to the FAST
IDLE switch on the lower,
driver's side of the
instrument panel.
This light will illuminate whenever the manual FAST
IDLE feature is engaged. For more details about this
system, see ªFast Idle Systemº in the Index.
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2-64 Service Trans Filter Indicator Light
(If Equipped)
If your vehicle has this
light, you'll find it
below the cluster on the
instrument panel.
It monitors the transmission fluid filter. If it ever
goes on, it means your transmission filter is dirty and
requires replacement.
Malfunction Indicator Lamp
(Check Engine Light)
If your vehicle is equipped
with either a gasoline
engine or an electronically
controlled diesel engine,
you will have this light.
If this light comes on or flashes while you are driving,
two things may happen.
First, you won't notice any difference in engine
performance, but your tail pipe emissions may increase.
Second, your engine may not run properly or may stall
without warning. If either of these things happen, drive
or tow your vehicle to your dealer for service.
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2-65
This light should come on when the ignition is on, but
the engine is not running, as a check to show you it is
working. If it does not come on at all, have it repaired.
NOTICE:
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.
Engine Oil Pressure Gage
Gasoline Engine Diesel Engine
The engine oil pressure gage, on the lower right portion
of your instrument cluster, shows engine oil pressure
in psi (pounds per square inch) or in kPa (kilopascals).
Oil pressure may vary with outside temperature and oil
viscosity, but readings of 30 to 40 psi (205 to 275 kPa)
on gasoline engines at operating temperature and
moderate road speeds are normal. If you have a diesel
engine, the normal operating range should be between
35 and 70 psi (240 to 480 kPa).
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2-66
A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
If you have a Caterpillar

diesel engine, also see your
Caterpillar
Operation & Maintenance Manual.
CAUTION:
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.
NOTICE:
Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
Change Oil Light (If Equipped)
The CHANGE OIL light
should come on briefly as a
bulb check when you start
the engine. If the light
doesn't come on, have
it serviced.
If the CHANGE OIL light comes on and stays on after
you start the engine, have the oil changed.
For additional information, see ªEngine Oil, When to
Changeº in the Index. To reset the Oil Life Monitor, see
ªEngine Oil Life Monitorº in the Index.
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2-67 Daytime Running Lamps (DRL)
Indicator Light
This light is located on the
upper cluster portion of the
instrument panel. It goes on
whenever the Daytime
Running Lamps are on. See
ªDaytime Running Lampsº
in the Index.
When it begins to get dark, the DRL indicator light is a
reminder to turn on your headlamps.
Check Gages Indicator Light (If Equipped)
This light will come on as
you're starting the engine,
just as a check.
If it ever comes on and stays on while you are driving,
however, it means that either your engine coolant
temperature gage or your engine oil pressure gage may
be showing a reading in the warning zone.
When the CHECK GAGES light comes on, you will
also hear a warning tone. The tone and the light will stay
activated until the problem is corrected.
This light may also come on if your vehicle is equipped
with the optional automatic engine shutdown system and
engine shutdown has begun. See ªEngine Automatic
Shutdownº in the Index.
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3-5
OFF
Press this button to turn the air conditioning/heating
system off. Pressing OFF will erase the present mode of
operation from the system's memory. Outside air will
still come out of the heater outlet whenever the vehicle
is moving forward.
If the OFF button is pressed, you must press A/C,
MAX or one of the BLEND buttons to turn the system
back on.
Air Conditioning
When you first turn on your vehicle's air conditioning,
open the windows long enough to clear the vehicle of
hot air, then close them. Using the MAX button can also
help. See ªMAX Buttonº earlier in this section for
more information.
For normal cooling on hot days, use A/C with the
temperature selector toward C.
When you press the A/C button to turn the air
conditioner off, the system will operate in the vent
mode. When you turn the air conditioner back on, the
system will operate in the mode you last selected unless
the OFF button was pressed.If your air conditioner develops high system pressure, it
will automatically go into the MAX mode and REC will
light on your display. The A/C system will remain in the
MAX mode, even if you press the MAX button, until
system pressure returns to a normal level.
Heating
On cold days, use HEATER with the temperature
selector all the way toward H. When the inside of the
vehicle has reached a comfortable temperature, maintain
it by using the temperature selector bar.
If your vehicle is equipped with a diesel engine, and the
engine has been idling for a long time when it's cold
outside, your heater may blow out cool air. This is
normal. When you increase the engine speed under load,
your heater should blow out warmer air. If it doesn't,
your coolant level may be low. See ªEngine Coolantº in
the Index to check your coolant level.
While idling your diesel engine, you can use the MAX
button to recirculate the air in the cab to help maintain
interior heat. This will preserve engine coolant temperature
and cab heat when idling cannot be avoided.
Using the MAX button while driving is not recommended
because interior window fogging can result.
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3-11 Tips About Your Audio System
Hearing damage from loud noise is almost undetectable
until it is too late. Your hearing can adapt to higher
volumes of sound. Sound that seems normal can be loud
and harmful to your hearing. Take precautions by
adjusting the volume control on your radio to a safe
sound level before your hearing adapts to it.
To help avoid hearing loss or damage:

Adjust the volume control to the lowest setting.

Increase volume slowly until you hear comfortably
and clearly.NOTICE:
Before you add any sound equipment to your
vehicle
-- like a tape player, CB radio, mobile
telephone or two
-way radio -- be sure you can
add what you want. If you can, it's very
important to do it properly. Added sound
equipment may interfere with the operation of
your vehicle's engine, Delco Electronics radio or
other systems, and even damage them. Your
vehicle's systems may interfere with the
operation of sound equipment that has been
added improperly.
So, before adding sound equipment, check with
your dealer and be sure to check Federal rules
covering mobile radio and telephone units.
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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.
Hydraulic Brake Systems
If your engine stops running, or if your primary brake
system stops working, your vehicle has a reserve power
assist system to help you slow down. Just slowly and
steadily apply the brake pedal until you can safely get
off the road. The pedal will seem harder to push down.
Don't pump the pedal; the system won't work well or at
all that way.You may find that the steering wheel seems hard to turn
when you're turning and braking at the same time. Also,
the PRIMARY BRAKE warning light may come on and
the warning tone may sound. This is normal because the
main hydraulic brake system and power steering both
use the power steering pump. If this ever happens, let up
on the brake pedal a little. When you let up on the brake
pedal in that situation, it lets the steering get a little
more help from the pump.
Anti-Lock Brakes (Option)
Your vehicle may have anti-lock brakes (ABS). ABS is
an advanced electronic braking system that will help
prevent a braking skid.
If your vehicle has anti-lock
brakes, this warning light on
the instrument panel will
come on briefly when you
start your vehicle.
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.
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4-21
Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to move
slightly slower at night.
When you want to leave the freeway, move to the proper
lane well in advance. If you miss your exit, do not,
under any circumstances, stop and back up. Drive on to
the next exit.
The exit ramp can be curved, sometimes quite sharply.
The exit speed for cars
-- but not larger vehicles -- is
usually posted. You should go more slowly.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are going
slower than you actually are.
Highway Hypnosis
Is there actually such a condition as ªhighway hypnosisº?
Or is it just plain falling asleep at the wheel? Call it
highway hypnosis, lack of awareness, or whatever.When you drive the vehicle for a long distance, there is
something about an easy stretch of road with the same
scenery, along with the hum of the tires on the road, the
drone of the engine, and the rush of the wind against the
vehicle that can make you sleepy. Don't let it happen to
you! If it does, your vehicle can leave the road in less
than a second, and you could crash and be injured.
What can you do about highway hypnosis? First, be
aware that it can happen.
Then here are some tips:

Make sure your vehicle is well ventilated, with a
comfortably cool interior.

Keep your eyes moving. Scan the road ahead and
to the sides. Check your mirrors and your
instruments frequently.

If you get sleepy, pull off the road into a rest, service
or parking area and take a nap, get some exercise, or
both. For safety, treat drowsiness on the highway as
an emergency.
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4-22
Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in flat or rolling terrain.Here are some tips that can make your drive through
steep country safer:

Keep the vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.

Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a
hill. You could crash. Shift down to let your
engine assist your brakes on a steep
downhill slope.
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