WE WAS DRIVING OUR 2004 GMC YUKON ON A GRAVEL ROAD AND THE ABS LIGHT AND THE TRAC CONTROL LIGHT CAME ON AND WONT GO OFF

C0040 - Right Front Wheel Speed Circuit Malfunction
C0550 - ECU Malfunction - internal write / checksum malfunction
C0455 - Either:

• A bent terminal or poor connection at the SWPS may be one possible cause; or
• The vehicle stability enhancement system (VSES) electronic brake control module (EBCM) calibration may be the other possible cause.

C0296 - Transfer Case Delivered Torque for Stability Control System Circuit
http://www.obd-codes.com/trouble_codes/obd-ii-c-chassis-codes.php

U1054 is no communication with Rear HVAC control module and is not connected to the Trac Off lt.
Need to have truck scanned and look at ABS and PCM for codes and go from there.

either abs sensor failing or damaged and or hub failing the abs system is incorporated into the hub have vehicle scanned most auto stores offer this service for free

when ur driving and u take off fast from a stop sign or light or turn and one or more of the tires slip from wet road ,sand on road or ice on road anything that causes a tire to slip will set off the traction control ---if it is on steady or coming on and off while on a dry road check the abs sensor wiring first if looks good will need to have truck scanned will probably have a pending or a fault code in computer most auto stores will scan a vehicle for free check ur local area the code will assist in locating the problem so a repair can be made

Wheel hub bearing . When the ABS see's a problem will disable traction control an ABS an will turn on RED brake light as well . Fluid level has nothing to do with it .
SERVICE STABILITY
Refer to ABS Description and Operation in Antilock Brake Systems

CHECK FUSES TO BRAKE AND ABS BRAKE SYSTEM.IF FUSE OKAY NO BLOWED BULBS. YOU HAVE A ELECTRICAL PROBLEM IN BRAKES AND ABS BRAKE UNIT.THE DEALERSHIP HAS TO FIX.

wheel bearing went bad abs trac control use same sensor engine light is from pcm for abs problem

The ABS and TRAC lights are on because the system detects a fault with both systems (which share the same components) There may be a bad wheel speed sensor, abs module, even something as simple as a brake switch. The computer will have to be scanned to see what codes were set and then diagnosed further from there to determine what the fault is.

Trac is the control that doesnt let your tires spin when they are not making contact with the road. Just by having your emergency brake on will light up the trac light. It also come on with your abs. If you driving on a slick road and you jam on your brakes and the tires slide a little mine will say low track on my car.

ok your problem is that your brakes are under force you shold get new brake pads ok