engine GMC YUKON XL 2002 Repair Manual

5-4 2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved
in the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
NOTICE: If you leave your radio on, it could be badly
damaged. The repairs wouldn't be covered by
your warranty. 3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off the radio
and all lamps that aren't needed. This will avoid
sparks and help save both batteries. And it could
save your radio!
4. Open the hoods and locate the positive (+) and
negative (
- ) terminal locations of the other vehicle.
Your vehicle has a remote positive (+) jump starting
terminal and a remote negative (
- ) jump starting
terminal. You should always use these remote
terminals instead of the terminals on the battery.
The remote positive (+) terminal is located under a
red plastic cover near the engine accessory drive
bracket. To access the remote positive (+) terminal,
open the red plastic cover.
The remote negative (
- ) terminal is located on
the engine accessory drive bracket and is
marked ªGNDº.
See ªEngine Compartment Overviewº in the Index
for more information on location.

5-5CAUTION:Using a match near a battery can cause battery
gas to explode. People have been hurt doing this,
and some have been blinded. Use a flashlight if
you need more light.
Be sure the battery has enough water. You don't
need to add water to the ACDelco

battery
installed in every new GM vehicle. But if a
battery has filler caps, be sure the right amount
of fluid is there. If it is low, add water to take
care of that first. If you don't, explosive gas could
be present.
Battery fluid contains acid that can burn you.
Don't get it on you. If you accidentally get it in
your eyes or on your skin, flush the place with
water and get medical help immediately. 5. Check that the jumper cables don't have loose or
missing insulation. If they do, you could get a shock.
The vehicles could be damaged too.
Before you connect the cables, here are some basic
things you should know. Positive (+) will go to
positive (+) or to a remote positive terminal (+) if the
vehicle has one. Negative (
- ) will go to a heavy,
unpainted metal engine part or to a remote negative
(
- ) terminal, if the vehicle has one.
Don't connect positive (+) to negative (
- ) or you'll
get a short that would damage the battery and maybe
other parts too.
CAUTION: Fans or other moving engine parts can injure you
badly. Keep your hands away from moving parts
once the engine is running.

5-6 6. Connect the red
positive (+) cable to
the positive (+) terminal
of the dead battery. Use
a remote positive (+)
terminal if the vehicle
has one.
7. Don't let the other end
touch metal. Connect it
to the positive (+)
terminal of the good
battery. Use a remote
positive (+) terminal if
the vehicle has one. 8. Now connect the black
negative (
- ) cable to the
negative (
- ) terminal of
the good battery. Use a
remote negative (
- )
terminal if the
vehicle has one.
Your vehicle's remote
negative (
- ) terminal is
marked GND.
Don't let the other end touch anything until the next
step. The other end of the negative (
- ) cable doesn't go
to the dead battery. It goes to a heavy, unpainted metal
engine part or to a remote negative (
- ) terminal on the
vehicle with the dead battery.

5-79. Connect the other end
of the negative (
- )
cable at least 18 inches
(45 cm) away from the
dead battery, but not
near engine parts that
move.
The electrical connection is just as good there, and
the chance of sparks getting back to the battery is
much less. 10. Now start the vehicle with the good battery and run
the engine for awhile.
11. Try to start the vehicle that had the dead battery.
If it won't start after a few tries, it probably
needs service.
NOTICE: Damage to your vehicle may result from
electrical shorting if jumper cables are removed
incorrectly. To prevent electrical shorting, take
care that they don't touch each other or any
other metal. The repairs wouldn't be covered by
your warranty.

5-8 Jumper Cable Removal
A. Heavy, Unpainted Metal Engine Part or Remote
Negative (
- ) Terminal.
B. Good Battery or Remote Positive (+) and
Negative (
- ) Terminals.
C. Dead Battery or Remote Positive (+) Terminal. To disconnect the jumper cables from both vehicles
do the following:
1. Disconnect the black negative (
- ) cable from the
vehicle that had the dead battery.
2. Disconnect the black negative (
- ) cable from the
vehicle with the good battery.
3. Disconnect the red positive (+) cable from the
vehicle with the good battery.
4. Disconnect the red positive (+) cable from the
other vehicle.
5. Return the positive (+) remote terminal cover to
its original position.

5-9Towing Your Vehicle Consult your dealer or a professional towing service
if you need to have your disabled vehicle towed.
See ªRoadside Assistanceº in the Index.
Engine Overheating You will find a coolant temperature gage on your
vehicle's instrument panel. See ªEngine Coolant
Temperature Gageº in the Index. In addition, you will
find a LOW COOLANT, CHECK COOLANT TEMP,
ENGINE OVERHEATED and a REDUCED ENGINE
POWER message in the message center on the
instrument panel. See ªMessage Centerº in the Index. Overheated Engine Protection
Operating Mode If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates firing groups
of cylinders helps prevent engine damage. In this mode,
you will notice a loss in power and engine performance.
This operating mode allows your vehicle to be driven to
a safe place in an emergency. Driving extended miles
(km) and/or towing a trailer in the overheat protection
mode should be avoided.
NOTICE: After driving in the overheated engine protection
operating mode, to avoid engine damage, allow
the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair
the cause of coolant loss, change the oil and reset
the oil life system. See ªEngine Oilº in the Index.

5-10If Steam Is Coming From Your Engine
CAUTION:Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine if you see or hear steam coming
from it.
CAUTION: (Continued) CAUTION: (Continued)
Just turn it off and get everyone away from
the vehicle until it cools down. Wait until there
is no sign of steam or coolant before you open
the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch fire. You or
others could be badly burned. Stop your engine if
it overheats, and get out of the vehicle until the
engine is cool. See ªOverheated Engine
Protection Operating Modeº in the Index.
NOTICE: If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty. See ªOverheated
Engine Protection Operating Modeº in the Index.

5-11If No Steam Is Coming From Your Engine An overheat warning, along with a low coolant message,
can indicate a serious problem. See ªLow Coolant
Messageº in the Index.
If you get an engine overheat warning but see or hear no
steam, the problem may not be too serious. Sometimes
the engine can get a little too hot when you:

Climb a long hill on a hot day.

Stop after high
- speed driving.

Idle for long periods in traffic.

Tow a trailer. See ªDriving on Gradesº in the Index.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
2. If you're in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
-- DRIVE (D). If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn't come back on, you can
drive normally.
If the warning continues, pull over, stop, and park
your vehicle right away.
If there's still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you're parked. If you still have the warning, turn off the
engine and get everyone out of the vehicle until it cools
down. Also, see ªOverheated Engine Protection
Operating Modeº listed previously in this section.
You may decide not to lift the hood but to get service
help right away.

5-12Cooling System When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Fan
If the coolant inside the coolant surge tank is boiling,
don't do anything else until it cools down. The vehicle
should be parked on a level surface. The coolant level should
be at or above the FILL
COLD mark. If it isn't,
you may have a leak at the
pressure cap or in the
radiator hoses, heater
hoses, radiator, water
pump or somewhere else
in the cooling system.
CAUTION: Heater and radiator hoses, and other engine
parts, can be very hot. Don't touch them. If you
do, you can be burned.
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.

5-13If there seems to be no leak, start the engine again.
The engine cooling fan speed should increase when idle
speed is doubled by pushing the accelerator pedal down.
If it doesn't, your vehicle needs service. Turn off
the engine.
NOTICE: Engine damage from running your engine
without coolant isn't covered by your warranty.
See ªOverheated Engine Protection Operating
Modeº in the Index. NOTICE: When adding coolant, it is important that you
use only DEX
- COOL

(silicate
- free) coolant.
If coolant other than DEX
- COOL is added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the
use of coolant other than DEX
- COOL

is not
covered by your new vehicle warranty.