brake GMC YUKON 2000 Repair Manual

6-18
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.
To get the right reading, the fluid should be at
normal operating temperature, which is 180F to
200F (82C to 93C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above
50F (10C). If it's colder than 50F (10C),
drive the vehicle in THIRD (3) until the engine
temperature gage moves and then remains steady
for 10 minutes. Then follow the hot check procedures.Checking Transmission Fluid Cold
A cold check is made after the vehicle has been sitting
for eight hours or more with the engine off and is used
only as a reference. Let the engine run at idle for five
minutes if outside temperatures are 50F (10C) or
more. If it's colder than 50F (10C), you may have
to idle the engine longer. Should the fluid level be low
during a cold check, you must perform a hot check
before adding fluid. This will give you a more accurate
reading of the fluid level.
Checking the Fluid Level
Prepare your vehicle as follows:

Park your vehicle on a level place. Keep the
engine running.

With the parking brake applied, place the shift
lever in PARK (P).

With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).

Let the engine run at idle for three minutes or more.

6-28
Brakes
Brake Fluid
Your brake master cylinder
reservoir is filled with
DOT
-3 brake fluid.
There are only two reasons why the brake fluid level
in the reservoir might go down. The first is that the
brake fluid goes down to an acceptable level during
normal brake lining wear. When new linings are put in,
the fluid level goes back up. The other reason is that
fluid is leaking out of the brake system. If it is, you
should have your brake system fixed, since a leak
means that sooner or later your brakes won't work well,
or won't work at all.So, it isn't a good idea to ªtop offº your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work is
done on the brake hydraulic system.
CAUTION:
If you have too much brake fluid, it can spill
on the engine. The fluid will burn if the engine
is hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
fluid only when work is done on the brake
hydraulic system.
Refer to the Maintenance Schedule to determine when
to check your brake fluid. See ªPeriodic Maintenance
Inspectionsº in the Index.

6-29
Checking Brake Fluid
You can check the brake fluid without taking off the cap.
Just look at the brake fluid reservoir. The fluid level
should be above MIN. If it isn't, have your brake
system checked to see if there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not over
the MAX mark.What to Add
When you do need brake fluid, use only DOT
-3 brake
fluid. Refer to ªRecommended Fluids and Lubricantsº
in the Index. Use new brake fluid from a sealed
container only.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This will help keep
dirt from entering the reservoir.
CAUTION:
With the wrong kind of fluid in your brake
system, your brakes may not work well, or they
may not even work at all. This could cause a
crash. Always use the proper brake fluid.

6-30
NOTICE:

Using the wrong fluid can badly damage
brake system parts. For example, just a few
drops of mineral
-based oil, such as engine
oil, in your brake system can damage brake
system parts so badly that they'll have to
be replaced. Don't let someone put in the
wrong kind of fluid.

If you spill brake fluid on your vehicle's
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake
fluid on your vehicle. If you do, wash it off
immediately. See ªAppearance Careº in
the Index.
Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built
-in wear indicators that make
a high
-pitched warning sound when the brake pads
are worn and new pads are needed. The sound may
come and go or be heard all the time your vehicle is
moving (except when you are pushing on the brake
pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead
to an accident. When you hear the brake wear
warning sound, have your vehicle serviced.

6-31
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly applied.
This does not mean something is wrong with your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly torque wheel nuts in the
proper sequence to GM specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of this
manual under Part C ªPeriodic Maintenance Inspections.º
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together
if the vehicle is to have really good braking. Your
vehicle was designed and tested with top
-quality
GM brake parts. When you replace parts of your braking
system
-- for example, when your brake linings wear
down and you have to have new ones put in
-- be sure
you get new approved GM replacement parts. If you
don't, your brakes may no longer work properly.
For example, if someone puts in brake linings that
are wrong for your vehicle, the balance between your
front and rear brakes can change
-- for the worse.
The braking performance you've come to expect can
change in many other ways if someone puts in the
wrong replacement brake parts.

6-44
NOTICE:
The wrong wheel can also cause problems with
bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper
height, vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
See ªChanging a Flat Tireº in the Index for
more information.
Used Replacement Wheels
CAUTION:
Putting a used wheel on your vehicle is dangerous.
You can't know how it's been used or how far it's
been driven. It could fail suddenly and cause an
accident. If you have to replace a wheel, use a new
GM original equipment wheel.
Tire Chains
NOTICE:
If your vehicle has P265/75R16, LT265/75R16,
P265/70R16 or P265/70R17 size tires, don't use
tire chains. They can damage your vehicle
because there's not enough clearance.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer's
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it's contacting your vehicle, and don't
spin your wheels.
If you do find traction devices that will fit,
install them on the rear tires.
NOTICE: (Continued)

6-57
NAME Usage
LOCK Power Door Lock Relay
HVAC 1 Climate Control System
CRUISE Cruise Control, Instrument Cluster
IGN 3 Ignition, Power Seats
4WD Four
-Wheel Drive System,
Auxiliary Battery
CRANK Starting System
INT PRK Parking Lamps, Sidemarker
Lamps, Interior Lamps
L DOOR Power Door Lock Relay
BRAKE Anti
-Lock Brake System
RR WIPER Rear Window Wiper
ILLUM Interior Lamps
SEAT Power Seat Circuit Breaker
TURN Exterior Lamps, Turn Signals,
Hazard Lamps
UNLOCK Power Door LocksNAME Usage
HTR A/C Climate Control System
WS WPR Windshield Wipers
IGN 1 Ignition, Instrument Panel
AIR BAG Air Bag
MIR/LOCK Power Mirrors, Power Door Locks
DR LOCK Power Door Locks
PWR WDO Power Window Circuit Breaker
UNLOCK Power Door Lock Relay
IGN 0 PRND321 Display, Odometer,
VCM/PCM
SEO IGN Special Equipment Option,
Ignition
SEO ACCY Special Equipment Option
Accessory, Cellular Telephone
RAP #1 Retained Accessory Power Relay
RDO 1 Audio System
RAP #2 Rear Power Windows,
Sunroof, Radio

6-58
Center Instrument Panel Utility Block
The center instrument panel utility block is located
underneath the instrument panel, to the left of the
steering column.Relay Name Usage
SEO Special Equipment Option
HTD ST Heated Seats
HDLNR Headliner
VANITY Headliner Wiring
TRAILER Trailer Brake Wiring
PWR ST Power Seats
YE9 Not Used
UPF Upfitter
PARK LAMP Parking Lamps
FRT PRK EXPT Not Used
SPARE 2 Not Used
PUDDLE LP Not Used
SL RIDE Not Used
SPARE 3 Not Used
INADV PWR Interior Lights Feed
CTSY LP Courtesy Lamps
CEL PHONE Cellular Telephone Wiring

6-61
Name Usage
STUD #1 Accessory Power/Trailer
Wiring Feed/Load Leveling
ABS Anti
-Lock Brakes
IGN A Ignition Switch
AIR A.I.R. System
RAP #1 Retained Accessory Power,
Power Mirrors, Power Door
Locks, Power Seat(s)
IGN B Ignition Switch
RAP #2 Retained Accessory Power/Rear
Power Windows, Sunroof, Radio
STUD #2 Accessory Power/Trailer Wiring
Brake Feed
TRL R TRN Right Turn Signal Trailer Wiring
TRL L TRN Left Turn Signal Trailer Wiring
IGN 1 Ignition, Fuel Controls
INJ B Ignition, Fuel Controls (Relay)
STARTER Starter (Relay)
PARK LP Parking LampsName Usage
FRT HVAC Climate Control System
STOP LP Exterior Lamps, Stoplamps
ECM 1 VCM/PCM
CHMSL Center High Mounted Stoplamp
VEH STOP Stoplamps, Cruise Control
TRL B/U Backup Lamps Trailer Wiring
INJ A Fuel Controls, Ignition
RR HVAC Rear HVAC
VEH B/U Vehicle Backup Lamps
ENG 1 Engine Controls, Canister Purge,
Fuel System
ETC Electronic Throttle Control
IGN E A/C Compressor Relay, Rear
Window Defogger, Daytime
Running Lamps, A.I.R. System
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case

Scheduled Maintenance
7-5
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services
shown at 150,000 miles (240 000 km) and
200,000 miles (332 000 km) should be performed
at the same intervals after 150,000 miles (240 000 km)
and 200,000 miles (332 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.Footnotes

The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under
ªPeriodic Maintenance Inspectionsº in Part C of
this schedule.