Page 90 of 386
2-15
Ignition Positions
With your key in the ignition switch, you can turn it to
five different positions.
A (ACCESSORY): This position allows you to
use things like the radio, power windows and the
windshield wipers when the engine is off. To get into
ACCESSORY, push in the key and turn it toward you.
Your steering wheel will remain locked, just as it was
before you inserted the key.
B (LOCK): This position locks your ignition, steering
wheel and transmission. It's a theft
-deterrent feature.
You will only be able to remove your key when the
ignition is turned to LOCK.
C (OFF): This position lets you turn off the engine but
still turn the steering wheel. It doesn't lock the steering
wheel like LOCK. Use OFF if you must have your
vehicle in motion while the engine is off (for example, if
your vehicle is being pushed).
D (RUN): This is the position for driving.
E (START): This position starts your engine.
Page 92 of 386

2-17 Starting Your Engine
1. Without pushing the accelerator pedal, turn your
ignition key to START. When the engine starts, let
go of the key. The idle speed will go down as your
engine gets warm.
2. If the engine doesn't start in 10 seconds, push the
accelerator pedal all the way down and crank the
engine for five more seconds, unless it starts sooner.
3. If your engine still won't start (or starts but then
stops), it could be flooded with too much gasoline.
Wait 15 seconds to let the starter motor cool down.
Do Steps 1 through 3 again.
When the engine starts, let go of the key and the
accelerator pedal.NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
NOTICE:
If you ever need to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.
Page 94 of 386

2-19
Starting the Diesel Engine
If you have a Caterpillar diesel engine, also refer to your
Caterpillar Diesel Engine Operation & Maintenance
Manual for starting procedure.
For vehicles with the DURAMAX diesel engine, also
see ªStarting Your DURAMAX Diesel Engineº
following.
To make starting easier in cold weather (below 32F or
0C), the proper viscosity engine oil should be used.
See ªEngine Oilº in the Index. It's also best to heat the
engine oil first. You can do this by using an engine
coolant heater.
NOTICE:
If you ever need to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.
Restarting the Diesel Engine While Moving
(Automatic Transmission)
If you have to restart the engine while the vehicle is
moving, you'll first have to shift the automatic
transmission to NEUTRAL (N). This safety feature
prevents starting the engine when the transmission is
in a drive gear.
Stopping the Diesel Engine
If you have a Caterpillar diesel engine, see your
Caterpillar Diesel Engine Operation &
Maintenance Manual.
1. Set the parking brake and shift to NEUTRAL (N)
or PARK (P).
2. Turn the ignition key to OFF.
If your vehicle has a two
-speed axle, see ªRear Axle,
Tw o
-Speed Electric Shift Controlº or ªRear Axle,
Tw o
-Speed Airshift Controlº in the Index.
Page 95 of 386

2-20 Cold Weather Starting
(Caterpillar
Diesel)
Because the diesel engine uses compression ignition, it
is harder to start in cold weather than a gasoline engine.
The air intake heater and use of the proper engine oil,
optional engine coolant heaters and optional ether
injection systems help cold weather starting. See the
Caterpillar
Diesel Engine Operation & Maintenance
Manual for more information.
NOTICE:
Your diesel engine has an electric air intake
heater system which reduces white smoke and
helps start the engine in cold weather. Do not
spray starting fluid into the air intake where it
can contact the heater elements.
If you don't have the GM Automatic Ether
Injection System, don't use starting fluid or you
could damage your engine. If you have the GM
system, use only GM approved starting fluid that
has been tested to establish compatibility with the
air inlet heater system.
Diesel Engine Warm-Up
Several factors affect how quickly your diesel engine
warms up. These can include outside temperature,
engine load, idle time and your vehicle's option content.
Your vehicle may be equipped with some features that
can help the engine reach operating temperature sooner.
Some of these features are discussed below.
Also, remember that an automatic transmission adds
heat to the cooling system through the heat exchanger in
the radiator. Because of this, vehicles equipped with
automatic transmissions are often able to retain engine
coolant heat better than manual transmission vehicles.
See your Caterpillar
Operation & Maintenance manual
for additional diesel engine warm
-up information.
Page 99 of 386

2-24
Starting Your DURAMAX
Diesel Engine
Your diesel engine starts differently than a
gasoline engine.
Automatic Transmission
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine won't start in any other position
-- that's
a safety feature. To restart when you're already moving,
use NEUTRAL (N) only.
NOTICE:
Don't try to shift to PARK (P) if your vehicle is
moving. If you do, you could damage the
transmission. Shift to PARK (P) only when your
vehicle is stopped.
Manual Transmission
Move your shift lever to neutral and hold the clutch
pedal to the floor while starting the engine. Your vehicle
won't start if the clutch pedal is not all the way
down
-- that's a safety feature.
Starting Your Engine
1. Turn your ignition key to RUN.
Observe the wait to start light. See ªWait To Start
Lightº in the Index. (This light may not come on
if the engine is hot.)
2. As soon as the wait to start light goes off,
IMMEDIATELY turn the ignition key to START.
When the engine starts, let go of the key.
NOTICE:
Holding your key in START for longer than
15 seconds at a time will cause your battery to be
drained much sooner. And the excessive heat can
damage your starter motor.
Page 100 of 386

2-25
NOTICE:
If the wait to start light stays on, it means that
your vehicle could have one of several problems,
so you should have it serviced right away.
3. If the engine does not start after 15 seconds of
cranking, turn the ignition key to OFF. Wait
one minute for the starter to cool, then try the
same steps again.
If you're trying to start your engine after you've run
out of fuel, follow the steps in ªRunning Out of Fuel.º
See ªDiesel Fuel Requirements and Fuel Systemº in
the Index.
When your engine is cold, let it run for a few minutes
before you move your vehicle. This lets oil pressure
build up. Your engine will sound louder when it's cold.
NOTICE:
If you're not in an idling vehicle and the engine
overheats, you wouldn't be there to see the
overheated engine condition. This could damage
your vehicle. Don't let your engine run when
you're not in your vehicle.
Cold Weather Starting (Diesel Engine)
The following tips will help you get good starting in
cold weather.
Use the recommended engine oil when the outside
temperature drops below freezing. See ªEngine Oilº in
the Index. When the outside temperature drops below
0F (
-18C), use of the engine coolant heater is
recommended.
If you experience longer cranking times, notice an
unusual amount of exhaust smoke or are at higher
altitudes (over 7,000 ft. or 2 135 m), you may use your
engine coolant heater. See ªEngine Coolant Heaterº in
the Index.
See ªDiesel Fuel Requirements and Fuel Systemº in the
Index for information on what fuel to use in cold weather.
Page 101 of 386

2-26 If Your Diesel Engine Won't Start
If you've run out of fuel, look at ªRunning Out of Fuel.º
See ªDiesel Fuel Requirements and Fuel Systemº in
the Index.
If you're not out of fuel, and your engine won't start,
do this:
Turn your ignition key to RUN. IMMEDIATELY
after the wait to start light goes off, 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.
If the light comes on and then goes off and you know
your batteries are charged, but your engine still won't
start, your vehicle needs service.
If the light does not come on when the engine is cold,
your vehicle needs service.If your batteries don't have enough charge to start your
engine, see ªBatteryº in the owner's manual.
Be sure you have the right oil for your engine, and that
you've changed the oil at the proper times. If you use
the wrong oil, your engine may be harder to start.
Be sure you are using the proper fuel for existing
weather conditions. See ªDiesel Fuel Requirements and
Fuel Systemº in the Index.
If the engine starts, runs a short time, then stops, your
vehicle needs service.
CAUTION:
Do not use gasoline or starting ªaids,º such as
ether, in the air intake. They could damage your
engine. There could also be a fire, which could
cause serious personal injury.
Page 102 of 386

2-27
Engine Checks Before Operating
When you've started your engine, let it run for 20 to
30 seconds before you put a load on the engine. But
don't leave the vehicle while the engine is running.
Avoid unnecessary idling of diesel engine equipped
vehicles.
If the engine idles too long, the temperature of the
engine coolant will fall below the normal operating
range. Low engine operating temperature causes several
conditions which affect engine operation and reduce
engine life.
The engine should be permitted to go through a
warm
-up period. Operate the vehicle at a minimum of
600 rpm during the warm
-up period. During this period
and during operation, the following observations should
be made.
During this warm
-up period, check your warning lights
and gages:
If oil pressure doesn't begin to rise within
15 seconds of starting, stop the engine and
find the cause.If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating.
If you have air brakes, the dual
-needle air pressure
gage should read at least 115 psi (790 kPa) for both
service systems before you try to move the vehicle.
When air pressure is below 60 psi (420 kPa), the
LOW AIR light will come on and you will hear a
tone alarm. If the pressure doesn't build up or
drops during warm
-up, stop the engine and find
the cause before you try to move the vehicle.
Recommended air pressure before actually driving
away is 120 psi (830 kPa).
The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above idle.
If the light doesn't go out or comes back on during
normal engine operation, have the charging system
checked right away. (This light tells you if the
generator is not charging; it doesn't reflect the
condition of the battery.)