brake sensor GMC YUKON 2004 Owner's Manual

In many crashes severe enough to inate an air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from the
right front passenger air bag.
Air bags are designed to inate only once. After an
air bag inates, you’ll need some new parts for
your air bag system. If you don’t get them, the air
bag system won’t be there to help protect you
in another crash. A new system will include air bag
modules and possibly other parts. The service
manual for your vehicle covers the need to replace
other parts.
Your vehicle is equipped with electronic frontal
sensors which help the sensing system distinguish
between a moderate and a more severe frontal
impact. Your vehicle is also equipped with a crash
sensing and diagnostic module, which records
information about the frontal air bag system. The
module records information about the readiness of
the system and when the system commands air
bag ination. It records the status of the driver’s
safety belt usage in a crash in which the air
bag deploys or a crash in which the air bag nearly
deploys. The module also records speed, engine
rpm, brake and throttle data.
Let only qualied technicians work on your air bag
systems. Improper service can mean that an air
bag system won’t work properly. See your dealer for
service.
Notice:If you damage the covering for the driver’s
or the right front passenger’s air bag, or the air
bag covering on the driver’s and right front
passenger’s seatback, the bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right front
passenger’s air bag, or both the air bag module
and seatback for the driver’s and right front
passenger’s side impact air bag. Do not open or
break the air bag coverings.
1-81

SERVICE TIRE MONITOR
If your vehicle is equipped with the tire pressure monitor
system, this message will be displayed if one or more of
the tire monitor sensors have malfunctioned, or if all of
the tire monitor sensors have not been programmed
successfully. Press the select button or reset stem, to
clear it from the display. The message will reappear at
each ignition cycle until the system has been serviced.
STABILITY SYS ACTIVE
You may see the STABILITY SYS ACTIVE message on
the DIC. It means that an advanced computer-controlled
system has come on to help your vehicle continue to
go in the direction in which you’re steering.
Stabilitrak
®activates when the computer senses that
your vehicle is just starting to spin, as it might if you hit
a patch of ice or other slippery spot on the road.
When the system activates, you may hear a noise or
feel a vibration in the brake pedal. This is normal. When
the STABILITY SYS ACTIVE message is on, you
should continue to steer in the direction you want to go.
The system is designed to help you in bad weather
or other difficult driving situations by making the most of
whatever road conditions will permit.
STABILITY SYS DISABLED
The STABILITY SYS DISABLED message will turn on
when you press the Stabilitrak®button, or when the
stability control has been automatically disabled. To limit
wheel spin and realize the full benets of the stability
enhancement system, you should normally leave
Stabilitrak
®on. However, you should turn Stabilitrak®off
if your vehicle gets stuck in sand, mud, ice or snow and
you want to “rock” your vehicle to attempt to free it, or if
you are driving in extreme off-road conditions and require
more wheel spin. SeeIf You Are Stuck: In Sand, Mud, Ice
or Snow on page 4-50. To turn the Stabilitrak
®system
back on press the Stabilitrak®button again. There are
four conditions that can cause this message to appear.
One condition is overheating, which could occur if
Stabilitrak
®activates continuously for an extended period
of time. The message will also be displayed if the brake
system warning light is on. SeeBrake System Warning
Light on page 3-46. The message could be displayed if
the stability system takes longer than usual to complete
its diagnostic checks due to driving conditions. Also, if an
engine or vehicle related problem has been detected, and
the vehicle needs service, the message will appear.
The message will turn off as soon as the conditions that
caused the message to be displayed are no longer
present.
3-75

TPM Sensor Identication Codes
Each TPM sensor has a unique identication code. Any
time you rotate your vehicle’s tires or replace one or
more of the TPM sensors, the identication codes
will need to be matched to the new tire/wheel position.
Each tire/wheel position is matched to a sensor, by
increasing or decreasing the tire’s air pressure.
The sensors are matched to the tire/wheel positions in
the following order: left front (LF); right front (RF);
right rear (RR) and left rear (LR).
You will have one minute to match the rst tire/wheel
position, and ve minutes overall to match all four
tire/wheel positions. If it takes longer than one minute,
to match the rst tire and wheel, or more than ve
minutes to match all four tire and wheel positions the
matching process stops and you will need to start over.
The TPM sensor matching process is outlined below:
1. Set the Parking brake.
2. Turn the ignition switch to RUN with the engine off.3. Turn the exterior lamp switch from “Off” to “On” four
times within 3 seconds. A double horn chirp will
sound and the TPM low tire warning light will begin to
ash. The double horn chirp and ashing TPM
warning light indicate that the TPM matching process
has started. The TPM warning light should continue
ashing throughout the matching procedure. The
SERVICE TIRE MONITOR message will be
displayed on the Driver Information Center (DIC).
4. Start with the left (driver’s side) front tire.
5. Remove the valve cap from the valve cap stem.
Activate the TPM sensor by increasing or decreasing
the tire’s air pressure for 10 seconds, then stop and
listen for a single horn chirp. The single horn chirp
should sound within 15 seconds, conrming that the
sensor identication code has been matched to this
tire and wheel position. If you do not hear the
conrming single horn chirp, you will need to start
over with step number one. To let air-pressure out of
a tire you can use the pointy end of the valve cap, a
pencil-style air pressure gage or a key.
5-74

*1— Gasoline Engine and Fuel Injection Rail #2.
*2— Gasoline Engine and Fuel Injection Rail #1.
*3— Gasoline Engine; Oxygen Sensors.
*4— Gasoline Engine; Oxygen Sensors.
*5— PCM Ignition
Fuses Usage
GLOW PLUG Not Used
CUST FEED Gasoline Accessory Power
STUD #1Auxiliary Power (Single
Battery and Diesels
Only)/Dual Battery (TP2) Do
not install fuse.
MBECMid Bussed Electrical Center
Power Feed, Front Seats,
Right Doors
BLOWER Front Climate Control Fan
LBECLeft Bussed Electrical Center,
Door Modules, Door Locks,
Auxiliary Power Outlet—Rear
Cargo Area and Instrument
Panel
STUD 2Accessory Power/Trailer
Wiring Brake Feed
Fuses Usage
ABS Anti-Lock Brakes
VSES/ECAS Vehicle Stability
IGN A Ignition Power
IGN B Ignition Power
LBEC 1Left Bussed Electrical Center,
Left Doors, Truck Body
Controller, Flasher Module
TRL PARK Parking Lamps Trailer Wiring
RR PARKRight Rear Parking and
Sidemarker Lamps
LR PARKLeft Rear Parking and
Sidemarker Lamps
PARK LP Parking Lamps Relay
STARTER Starter Relay
INTPARK Interior Lamps
STOP LP Stoplamps
TBC BATTTruck Body Controller Battery
Feed
SUNROOF Sunroof
SEO B2 Off-Road Lamps
5-119