1994 GMC SIERRA check engine light

NOTICE:
After you’ve used the coolant heater, be sure to store the cord in
the manner it was, to help keep it away from moving engine
parts.
If you don’t, it could be torn and damaged.
How long should you keep the coolant heater plugged in? The answer
depends on the weather,
the kind of oil you have, and some other things.
Follow this chart.
Engine Coolant Heater Usage
Viscosity/ 32°F
to 0°F
Oil Grade
(OOC to -1SOC)
SAE
1 OW-30
SAE
I5W-40
Not
Required
Not
Required
0°F to -10°F
(-18” C to -23 O C)
Two
Hours*
Two
Hours*
Below -10°F
Below -23 ” C
Eight Hours* or Overnight
Eight Hours”: or Overnight
*The times listed are minimum times. It
will not harm either the coolant
heater or the vehicle
to leave the coolant heater plugged in longer than the
times stated.
For best results
in cold weather, use Number I-D diesel fuel or a
“winterized” Number 2-D fuel.
lf Your Diesel Engine Won’t Start
If you’ve run out of fuel, look at “Running Out of Fuel” (see “Diesel Fuel
Requirements and Fuel System” in the Index).
If you’re not out of fuel, and your engine won’t start, do this:
Turn your ignition key to RUN. Make sure that the “GLOW PLUGS” light
is out. Then turn the ignition key to START.
If the light doesn’t go off, wait a few seconds, then try starting your engine
again. And, see
your dealer as soon as you can for a starting system check.
2- 18
ProCarManuals.com

Service Throttle Soon Light
The orange Service
Throttle Soon light,
if
you have one, is
located near the
middle left edge of the
instrument cluster
On diesel engines, a computer monitors the operation of the electronic
accelerator. This light should come on when the ignition is on but the engine
is not running, as a check to show you its working.
If it does not come on at
all, have it fixed right away. If the light stays on after the engine starts or
comes on while you are driving, the computer is indicating that you have a
problem. You should take your vehicle in for service soon.
Glow Plugs Light
The orange Glow
Plugs light, if you
have one, is located
near the upper right
corner
of the
instrument cluster.
If you have a diesel engine,
it has a special starting system. An instrument
panel Glow Plugs light tells you when the engine is ready
to be started. For
more details, see “Starting Your Diesel Engine” in the Index.
2-72
~. . ProCarManuals.com

Low Coolant Warning Light
The orange Low
Coolant Warning
light, if you have one,
is located
in the upper
left corner of the
instrument cluster.
If you have
on anytime
engine may a
diesel engine, you have a low coolant light. If this light comes
the engine is running, your system
is low on coolant and the
overheat. See “Engine Coolant”
in the Index and have your
vehicle serviced as soon as you can.
Charging System Warning Light
The red Charging
System Warning light
I is located at the upper
right corner
of the
instrument cluster.
The Charging System Warning light should come on briefly when
you turn
on the ignition, before starting the engine, as a check to show you it is
working. 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 alternator 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 air conditioner.
2-73
ProCarManuals.com

Malfunction Indicator (Service Engine Soon) Lamp
The orange
SERVICE
ENGINE
SOON
A computer monitors the operation of your fuel, ignition and emission
control systems. This light should come on when the ignition
is on but the
engine is not running,
as a check to show you its working. If it does not
come
on at all, have it fixed right away. If it stays on, or comes on while you
are driving, the computer is indicating that you have a problem. You should
take your vehicle in for service soon.
NOTICE:
If you keep driving your vehicle with this light on, after a while
the emission controls won’t work
as well, your fuel economy
won’t be as good, and your engine may not run as smoothly.
This could lead to costly repairs not covered by your warranty.
2-74
ProCarManuals.com

Check Gages Light
The orange Check
Gages light is located
near the lower right
corner
of the
instrument cluster.
This light
will come on briefly when you are starting the engine. 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. Chcck your various gages
to see if they
are
in the warning zones. If they are, have your vehicle serviced right away.
Daytime Running Lights (DRL) Indicator Light
(Canada Only)
The green Daytime
Running Lights
(DRL) Indicator light,
if you have one, is
located near the upper
center
of the
instrument cluster.
If your vehicle was first sold. when new. in Canada, you will have this green
lighl on the instrument pancl.
It will light whenever the Daytime Running
Lights
are on. For more details about DRL, sce "Headlights and Vehicle
Lighting'.
in this section.
2-75
ProCarManuals.com

FM Stereo
FM stereo will give you the best sound. But FM signals can only reach
about
10 to 40 miles (16 to 65 km). And, tall buildings or hills can interfere
with
FM signals, causing the sound to come and go.
AM
The range for most AM stations is greater than for FM, especially at night.
The longer range, however, can cause stations to interfere
with each other.
AM
can pick up noise from things like electrical storms and power lines. If
the noise interferes with your listening, try reducing the treble to lessen the
noise.
AM Stereo
This means the Delco@ system can receive C-QUAM@ stereo broadcasts.
Many AM stations around
the country use C-QUAM@ to produce stereo,
though some
do not. If your Delco@ system can get C-QUAM@, your
“STEREO” light will come on when you’re receiving it. (C-QUAM’ is a
registered trademark of Motorola, Inc.).
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@ radio or other
systems, and even damage them. And, 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.
3-10
ProCarManuals.com

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.
Before Leaving on a Long Trip
Make sure you’re ready. Try to be well rested. If you must start when you’re
not fresh
- such as after a day’s work - don’t plan to make too many
miles that first part
of the journey. Wear comfortable clothing and shoes you
can easily drive in.
Is your vehicle ready for a long trip? If you keep it serviced and maintained,
it’s ready to go.
If it needs service, have it done before starting out. Of
course, you’ll find experienced and able service experts
in Vehicle
dealerships all across
North America. They’ll be ready and willing to help if
you need it.
Here are some things you can check before a trip:
Windshield Washer Fluid: Is the reservoir full? Are all windows clean
inside and outside?
Wiper Blades: Are they in good shape‘?
Fuel, Engine Oil, Other Fluids: Have you checked all levels?
0 Lights: Are they all working? Are the lenses clean‘?
0 Tires: They are vitally important to a safe, trouble-free trip. Is the tread
good enough for long-distance driving‘? Are the tires all inflated
to the
recommended pressure‘?
0 Weather Forecasts: What’s the weather outlook along your route?
Should you delay your trip
a short time to avoid a major storm system?
0 Maps: Do you have up-to-date maps?
Highway Hypnosis
Is there actually such a condition as “highway hypnosis”? Or is it just plain
falling asleep at the wheel?
Call it highway hypnosis, lack of awareness, or
whatever.
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.
4-30
ProCarManuals.com

A CAUTION:
It can be dangerous to get out of your vehicle if the shift lever is
not fully in “P” (Park) with the parking brake firmly set. Your
vehicle can roll.
If’ you have left the engine running, the vehicle can move
suddenly. You or others could be injured.
To be sure your vehicle
won’t move, even when you’re on fairly level ground, use the
steps that follow.
If you have four-wheel drive and your transfer case is in “N”
(Neutral), your vehicle will be free to roll, even if your shift lever
is in
“P” (Park). So, be sure the transfer case is in a drive gear
- not in “N” (Neutral).
If you are parking on a hill, or if you’re pulling a trailer, also see
“Parking
On Hills” in the Index.
When You Are Ready to Leave After Parking on a Hill
1. Apply your regular brakes and hold the pedal down while you:
Start your engine;
Shift into a gear; and
0 Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re pulling a trailer. See
the Maintenance Schedule for more on this. Things that are especially
important in trailer operation are automatic
fluid (don’t overfill), engine oil,
axle lubricant, belts, cooling system, and brake adjustment. Each of these
is
covered in this manual, and the Index will help you find them quickly. If
you’re trailering, it’s
a good idea to review these sections before you start
your trip.
Check periodically to see that all hitch nuts and bolts are tight.
Trailer Light Wiring
See “Trailer Wiring Harness” in the Index.
4-44
ProCarManuals.com