My 2005 Chevy Uplander has traction control and ABS lights displayed, This all happened about the time the car needed brakes. I ve done the usual 4 wheel brake service, and the lights remain on. There is a bit of a "roaring noise" outside towards the left front, which seams to be related to the motion of the vehcile but not brakes.

SOURCE: Traction Contrl and ABS Light on

No, it is probably not related. Usually the ABS and traction control light is either a wheel sensor problem, located in one of the wheel bearings, or most likely in the wire harness from the wheel bearing sensor. Remove wires and spray clean with a good solvent electric spray, and check the condition of the receptacle. I have had these problems with my 02 AWD so many times it has become almost routine. GM really have a problem with this type of speed sensor in the wheel bearings. In the AWD model, it keeps the car in FWD if the ABS light is on for any reason. JUNK!

SOURCE: Abs

This is Simply the Computer System Letting you know that there has been an Unusual Action. If it was a Mechanical Problem it would stay on Constant and Flash Periodically.

SOURCE: 2005 CHEVY +TRAIL BLAZER ABS AND BRAKE LIGHTS ON

if chains caused problem and you have driven with them off light would have gone out once it saw everything working properly. look at sensors might have pulled a wire loose with chains. the abs system runs a self test everytime you start vehicle if it sees a history code from last time it will leave light on and look to see if that problem still exists and 99% of the time it will cut light off . but need to have scanned and checked out

SOURCE: traction system light and abs light come on at same time

You still have issues with the speed sensors. The wires that connect to the hubs are known for failure.

SOURCE: 2007 Chevrolet Uplander LT ABS and TC light on

We were having this problem...have your wheel bearing checked out. There was a sensor in the drivers side wheel bearing...once we replaced it (because it was going out) the ABS and Traction Control warning lights stopped coming on.