The abs light is comming on when you start the truck and not moving will only turn off if i turn it off then back on it will go away and i t will not turn on again for a week or so i hav a 2002 chevy avalanch 3/4 4x4 with 8.1

I'm sorry to say you need trained help or a good DIY neighbour to get to the bottom of this.; The ABS sensors on the rear brakes will not lead to air in the brakes or grinding of the brakes. It sounds like you have an ABS pump fault in the main unit. This can cause the brakes to hang up after releasing the pedal. The rear wheel ABS sensors may only need their mounting positions cleaned up and their location to the brake reset, this can be as little as 1-2mm. I'm sorry for your financial situation but you are going to need help and my advice is don't drive the car until you have it fixed. Your life or someone else's is in your hands.

start with the code go have it read most auto stores offer service for free instead of blindly throwing parts in --abs can be sensor wiring brakes or hub need to check and test vehicle sounds like in limp mode code and abs repair should reset it

That's telling us that the abs is passing the self check when you turn on the key. When th e light comes on after you start moving it usually means that a sensor is not sending a single or a signal is messed up. A scan tool will tell you wich wheel to focus on. It is fairly common for the exciter rings on the front drive axles to break and cause this code. It wouldn't hurt to inspect these for crackps or misalignment. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Any time the ABS light is on the traction control light will be on and the system will be disabled.

The ABS light is on because the ABS computer has detected a fault either in its self check if the light comes on at start up and stays on or when the vehicle is moving, the light will come on at start up then turn off and then come back on after the vehicle is moving.

The best advice I can give is have the ABS computer scanned for codes. This will give a good direction to head into to solve the problem. A high end muti-function scan tool or a ABS specific code reader will be needed to do this.

Once you know the code(s) post them and I'll be happy to help you further.

Some common problems I see on the minivans are rear speed sensors and broken exciter rings. The exciter rings will cause the light to come on after you start moving and can also have some other symptoms like overactive ABS and not turn on the light as well.

A bad speed sensor can cause the light to come on and stay on. There is a way to check them but you will need a good DVOM and know how to use it.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

check for codes with scanner it most likely is the abs sensor on the rear differential housing that is bad easy fix

The following lights all came on at the same time:
Brake light, ABS, BAS, ESP, and TCS, What does this mean.

Without knowing what year the truck is, what model, and we arent there to see what you did, ect????? You may have replaced the rotors with the incorrect ones. did they have the tone wheel for the ABS sensor? That would be the first thing to check. Whan you start the truck does the ABS light come on right away, or does it go off, then on again after you start moving.

When you first turn the key on the vehicle will perform and bulb check.for 2 seconds then the lights should go off.But they should never come on while driving.If they do it is because there is a fault in the ABS system.You need to get the codes to find out what could be causing the problem.Just post back when you get the codes and I`ll be glad to help you out.Good luck.

possible wheel speed sensor problem. need to check codes and data with proper scan tool.

IF it is not on when you start truck and comes on when you start moving or turn you have a wheel speed sensor losing signal. the only way to know which one is to have codes pulled. this is usually the problem