2001 GMC YUKON engine

2-16
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.
Ignition Positions
You can use your key to turn the ignition switch to
five different positions.
ACCESSORY (A): This position lets you use things
like the radio, power windows and the windshield
wipers when the engine is off. Push in the key and turn
it toward you.
LOCK (B): This position locks your ignition and
transmission. It's a theft
-deterrent feature. You will only
be able to remove your key when the ignition is turned
to LOCK.

2-17
NOTICE:
If your key seems stuck in LOCK and you can't
turn it, be sure you are using the correct key; if
so, is it all the way in? Turn the key only with
your hand. Using a tool to force it could break
the key or the ignition switch. If none of this
works, then your vehicle needs service.
OFF (C): This position lets you turn off the engine.
Use OFF if you must have your vehicle in motion while
the engine is off (for example, if your vehicle is
being pushed).
RUN (D): This is the position for driving.
START (E): This position starts your engine.
Retained Accessory Power (RAP)
(If Equipped)
Your vehicle may be equipped with a Retained
Accessory Power (RAP) feature which will allow
certain features on your vehicle to continue to work up
to 20 minutes after the ignition key is turned to OFF.Your radio, power windows, sunroof (if equipped), and
OnStar

System (if equipped) will work when the
ignition key is in RUN or ACCESSORY. Once the key
is turned from RUN to OFF, these features will continue
to work for up to 20 minutes or until a door is opened.
Starting Your Engine
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.
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts, let
go of the key. The idle speed will go down as your
engine gets warm.

2-18
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. Wait about
15 seconds between each try to help avoid
draining your battery or damaging your starter.
2. If it doesn't start within 10 seconds, push the
accelerator pedal all the way to the floor, while you
hold the ignition key in START. When the engine
starts, let go of the key and let up on the accelerator
pedal. Wait about 15 seconds between each try.
When starting your engine in very cold weather
(below 0
F or
-18
C), do this:
1. With your foot off the accelerator pedal, turn the
ignition key to START and hold it there. When the
engine starts, let go of the key. Use the accelerator
pedal to maintain engine speed, if you have to, until
your engine has run for a while.2. If your engine still won't start (or starts but then
stops), it could be flooded with too much gasoline.
Try pushing your accelerator pedal all the way to
the floor and holding it there as you hold the key in
START for about three seconds. When the engine
starts, let go of the key and accelerator. If the vehicle
starts briefly but then stops again, do the same
thing, but this time keep the pedal down for five or
six seconds. This clears the extra gasoline from
the engine.
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.

2-19
Engine Coolant Heater (If Equipped)
In very cold weather, 0
F
(
-18
C) or colder, the
engine coolant heater can
help. You'll get easier
starting and better fuel
economy during engine
warm
-up. Usually, the
coolant heater should be
plugged in a minimum of
four hours prior to starting
your vehicle.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver's side of the engine
compartment, near the power steering fluid reservoir.
3. Plug it into a normal, grounded 110
-volt AC outlet.
CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the wrong
kind of extension cord could overheat and cause
a fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't reach,
use a heavy
-duty three-prong extension cord
rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and store
the cord as it was before to keep it away from moving
engine parts. If you don't, it could be damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead of
trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for that
particular area.

2-20
Automatic Transmission Operation
There are several different positions for your shift lever.
Your vehicle is equipped with an automatic transmission
and features an electronic shift position indicator within
the instrument panel cluster. This display must be powered
anytime the shift lever is capable of being moved out of
PARK (P). This means that if your key is in OFF, rather
than LOCK, there will be a small current drain on your
battery which could discharge your battery over a period
of time. If you have to leave your key in the ignition in
OFF for an extended period, it is recommended that you
remove the IGN 0 fuse from the instrument panel fuse
block. See ªFuses and Circuit Breakersº in the Index.PARK (P): This locks your rear wheels. It's the best
position to use when you start your engine because your
vehicle can't move easily.
CAUTION:
It is dangerous to get out of your vehicle if the
shift lever is not fully in PARK (P) with the
parking brake firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. 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, always set your parking brake and
move the shift lever to PARK (P).
CAUTION: (Continued)

2-21
CAUTION: (Continued)
If you have four-wheel drive, your vehicle will
be free to roll
-- even if your shift lever is in
PARK (P)
-- if your transfer case is in
NEUTRAL. So, be sure the transfer case is in a
drive gear, two
-wheel high (2H) or four-wheel
high (4H) or four
-wheel low (4L) -- not in
NEUTRAL. See ªShifting Into PARK (P)º in the
Index. If you're pulling a trailer, see ªTowing a
Trailerº in the Index.
REVERSE (R): Use this gear to back up.
NOTICE:
Shifting to REVERSE (R) while your vehicle is
moving forward could damage your
transmission. Shift to REVERSE (R) only after
your vehicle is stopped.
To rock your vehicle back and forth to get out of snow,
ice or sand without damaging your transmission, see
ªStuck: In Sand, Mud, Ice or Snowº in the Index.
NEUTRAL (N): In this position, your engine
doesn't connect with the wheels. To restart when you're
already moving, use NEUTRAL (N) only. Also, use
NEUTRAL (N) when your two
-wheel drive vehicle is
being towed.
CAUTION:
Shifting out of PARK (P) or NEUTRAL (N) while
your engine is ªracingº (running at high speed) is
dangerous. Unless your foot is firmly on the
brake pedal, your vehicle could move very
rapidly. You could lose control and hit people or
objects. Don't shift out of PARK (P) or
NEUTRAL (N) while your engine is racing.

2-22
NOTICE:
Damage to your transmission caused by shifting
out of PARK (P) or NEUTRAL (N) with the
engine racing isn't covered by your warranty.
DRIVE (D): This position is for normal driving. If you
need more power for passing, and you're:

Going less than about 35 mph (56 km/h), push your
accelerator pedal about halfway down.

Going about 35 mph (56 km/h) or more, push the
accelerator all the way down.
You'll shift down to the next gear and have more power.
DRIVE (D) can be used when towing a trailer, carrying
a heavy load, driving on steep hills or for off
-road
driving. You may want to shift the transmission to
THIRD (3) or, if necessary, a lower gear selection if the
transmission shifts too often.THIRD (3): This position is also used for normal
driving, however it offers more power and lower fuel
economy than DRIVE (D).
SECOND (2): This position gives you more power but
lower fuel economy. You can use SECOND (2) on hills.
It can help control your speed as you go down steep
mountain roads, but then you would also want to use
your brakes off and on.
If you manually select SECOND (2) in a light duty
automatic transmission, the transmission will drive in
second gear. You may use this feature for reducing the
speed of the rear wheels when you are trying to start
your vehicle from a stop on slippery road surfaces.
FIRST (1): This position gives you even more power
(but lower fuel economy) than SECOND (2). You can
use it on very steep hills, or in deep snow or mud. If the
selector lever is put in FIRST (1) while the vehicle is
moving forward, the transmission won't shift into first
gear until the vehicle is going slowly enough.

2-23
NOTICE:
If your rear wheels can't rotate, don't try to
drive. This might happen if you were stuck in
very deep sand or mud or were up against a solid
object. You could damage your transmission.
Also, if you stop when going uphill, don't hold
your vehicle there with only the accelerator
pedal. This could overheat and damage the
transmission. Use your brakes or shift into
PARK (P) to hold your vehicle in position
on a hill.
On cold days, approximately 32
F (0
C) or colder, your
transmission is designed to shift differently until the
engine reaches normal operating temperature. This is
intended to improve heater performance.
Tow/Haul Mode Selector Switch
Your vehicle is equipped with a tow/haul mode. The
selector switch is located on the end of the column shift
lever. You can use this feature to assist when towing or
hauling a heavy load. See ªTow/Haul Modeº in the
Index for more information.
The tow/haul mode also interacts with the Autoride
feature, if your vehicle is so equipped, to enhance
the ride when trailering or with a loaded vehicle.
See ªAutorideº in the Index.