brakes are not working properly it is hard to stop and the warning light is on

If you have an ABS light on traction light, etc then you need to have it with a scan tool that can read ABS traction control etc codes.Most diyer scan tools cannot read them.

That is your starting point then you might even need a advanced scan tool that can read live ABS data and be able to activate different parts of the ABS.

Also, write down the exact code numbers not code descriptions that way you can post them on this question.