1999 GMC YUKON check engine light

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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.
Anti-Lock Brakes (ABS)
Your vehicle has anti-lock brakes (ABS). ABS is an
advanced electronic braking system that will help
prevent a braking skid.
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.
If there's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº in
the Index.

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4-41
CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will help
keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well
-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlamps. Let the heater run for a while.
Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.

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4-53 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

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 transmission fluid (don't
overfill), engine oil, axle lubricant, belt, 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 Wiring Harness
Light-Duty Wiring Harness

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5-5
4. Open the hoods and locate the batteries. Find the
positive (+) and negative (
-) terminals on
each battery.
CAUTION:
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 Freedom

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 (+) and negative (
-) will go to a heavy
unpainted metal engine part. 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.

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6-59
Fuse/Circuit
BreakerUsage
15 DRL Relay, Fog Lamp Relay
16 Front and Rear Turn Signals,
Back
-Up Lamps, BTSI Solenoid
17 Radio (Ignition)
18 4WAL/VCM, ABS, Cruise Control
19 Radio (Battery)
20 PRNDL, Automatic Transmission,
Speedometer, Check Gages,
Warning Lights
21 Security/Steering
22 Auxiliary Power, Headlamp Delay
23 Rear Wiper, Rear Washer Pump
24 Front Axle, 4WD Indicator Lamp,
TP2 Relay
A Power Door Lock, Six
-Way Power
Seat, Keyless Entry Module
B Power WindowsUnderhood Fuse/Relay Center
The underhood fuse/relay center is located in the rear of
the engine compartment near the brake fluid reservoir.
Move the retainer clips for the cover to access the
fuse block.
You can remove fuses with a fuse extractor. The fuse
extractor is mounted to the interior fuse block. To
remove fuses if you don't have a fuse extractor, hold the
end of the fuse between your thumb and index finger
and pull straight out.

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7-35
Part B: Owner Checks and Services
Listed in this part are owner checks and services which
should be performed at the intervals specified to help
ensure the safety, dependability and emission control
performance of your vehicle.
Be sure any necessary repairs are completed at once.
Whenever any fluids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown in
Part D.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuel fill.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. See ªEngine Oilº in the Index for
further details.
Engine Coolant Level Check
Check the engine coolant level and add DEX
-COOL

coolant mixture if necessary. See ªEngine Coolantº in
the Index for further details.Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the
windshield washer tank and add the proper fluid if
necessary. See ªWindshield Washer Fluidº in the Index
for further details.
At Least Once a Month
Tire Inflation Check
Make sure tires are inflated to the correct pressures.
See ªTiresº in the Index for further details.
Cassette Deck Service
Clean cassette deck. Cleaning should be done every
50 hours of tape play. See ªAudio Systemsº in the
Index for further details.
At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light and all your
belts, buckles, latch plates, retractors and anchorages are
working properly. Look for any other loose or damaged
safety belt system parts. If you see anything that might
keep a safety belt system from doing its job, have it
repaired. Have any torn or frayed safety belts replaced.

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9-4
Electronic Compass 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner/Filter 6-15, 6-64 . . . . . . . . . . . . . . . . . . . . . . . .
Coolant 6-23, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Heater 2-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Level Check 7-35 . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Gage 2-76 . . . . . . . . . . . . . . . . . . . . .
Cooling System 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust 2-36, 4-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identification 6-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Level Check 7-35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overheating 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Running While Parked 2-37 . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 6-63 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Your 2-22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Oil 6-11, 6-65, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additives 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Gage 2-79 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Used 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When to Change 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment, Adding to the Outside of Your Vehicle 6-3 . . . . . .
Ethanol 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust, Engine 2-36, 4-41 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exit Lighting and Delayed Illumination 2-49 . . . . . . . . . . . . .
Exterior Lamps 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabric Cleaning 6-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Feature Customization 2-16 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver's Door Alarm Delay 2-19 . . . . . . . . . . . . . . . . . . . . .
Keyless Entry Verification 2-17 . . . . . . . . . . . . . . . . . . . . . .
Leaving Programming Mode 2-19 . . . . . . . . . . . . . . . . . . . .
Lockout Prevention 2-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . Theft
-Deterrent Arming Method 2-18 . . . . . . . . . . . . . . . . .
Theft-Deterrent Arming Verification 2-19 . . . . . . . . . . . . . .
Filling a Portable Fuel Container 6-8 . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Air Cleaner 6-15, 6-64 . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Engine Oil 6-14, 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Care 6-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Damage 6-53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
First Gear, Automatic Transmission 2-27 . . . . . . . . . . . . . . . .
Flashers, Hazard Warning 5-2 . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Tire, Changing 5-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Capacities 6-63 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Leak Check 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluids and Lubricants 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fog Lamps 2-48, 6-36, 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . .
Folding the Rear Seat 1-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreign Countries, Fuel 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Four-Wheel Drive 2-28, 6-21 . . . . . . . . . . . . . . . . . . . . . . . . .
French Language Manual ii. . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle 6
-22, 7-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle Locking Feature 2-28 . . . . . . . . . . . . . . . . . . . . . . .
Front Park/Turn Signal Bulb Replacement 6-36, 6-61 . . . . . .
Front Sidemarker Lamp Bulb Replacement 6-36, 6-61 . . . . . .
Front Towing 5-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Canada 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filling a Portable Container 6-8 . . . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gage 2-82 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In Foreign Countries 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Capacity 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuses and Circuit Breakers 6-57 . . . . . . . . . . . . . . . . . . . . . . .

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9-6
Labels
Certification/Tire 4-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Parts Identification 6-55 . . . . . . . . . . . . . . . . . . . . .
Tire-Loading Information 4-43 . . . . . . . . . . . . . . . . . . . . . .
Vehicle Identification Number 6-55 . . . . . . . . . . . . . . . . . . .
Lamps 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic 2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning Exterior 6-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Delay 2-48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dome 2-49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exterior 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fog 2-48, 6-36, 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interior 2-49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On Reminder 2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Leaving Your Vehicle 2-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Leaving Your Vehicle with the Engine Running 2-34 . . . . . . .
Lighter 2-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lights
Air Bag Readiness 1
-25, 2-73 . . . . . . . . . . . . . . . . . . . . . . .
Anti-Lock Brake System Warning 2-75, 4-7 . . . . . . . . . . . .
Brake System Warning 2-74 . . . . . . . . . . . . . . . . . . . . . . . . .
Charging Warning System 2-73 . . . . . . . . . . . . . . . . . . . . . .
Check Gages 2-81 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Daytime Running Lamps Indicator 2-81 . . . . . . . . . . . . . . .
Headlamp High-Beam Indicator 2-81 . . . . . . . . . . . . . . . . .
Safety Belt Reminder 1-10, 2-72 . . . . . . . . . . . . . . . . . . . . .
Security 2-80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Engine Soon 2-76 . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Four-Wheel Drive 2-80 . . . . . . . . . . . . . . . . . . . . . .
Turn Signal and Lane Change Indicator 2-81 . . . . . . . . . . .
Loading Your Vehicle 4-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . Loading Your Vehicle for Off
-Road Driving 4-15 . . . . . . . . . .
Lockout Prevention 2-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Locks 2-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Child Security 2-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cylinder 7-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Door 2-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition Transmission Check 7-38 . . . . . . . . . . . . . . . . . . . .
Key Lock Cylinder Service 7-36 . . . . . . . . . . . . . . . . . . . . .
Power Door 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Window 2-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubricants and Fluids 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubrication, Weatherstrips 6-50, 7-36 . . . . . . . . . . . . . . . . . . .
Lubrication Service, Body 7-36 . . . . . . . . . . . . . . . . . . . . . . . .
Luggage Carrier 2-59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance, Normal Replacement Parts 6-65 . . . . . . . . . . .
Maintenance Record 7-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance Schedule 7-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Long Trip/Highway Definition 7-6 . . . . . . . . . . . . . . . . . . .
Long Trip/Highway Intervals 7-6 . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-35 . . . . . . . . . . . . . . . . . . . . .
Periodic Maintenance Inspections 7-39 . . . . . . . . . . . . . . . .
Recommended Fluids and Lubricants 7-41 . . . . . . . . . . . . .
Scheduled Maintenance Services 7-4 . . . . . . . . . . . . . . . . . .
Short Trip/City Definition 7-5 . . . . . . . . . . . . . . . . . . . . . . .
Short Trip/City Intervals 7-5 . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance, Underbody 6-53 . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance When Trailer Towing 4-53 . . . . . . . . . . . . . . . . .
Malfunction Indicator Lamp 2-76 . . . . . . . . . . . . . . . . . . . . . .
Methanol 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .