Brake Wear

Did you have your brakes serviced at a shop? It is their responsibility to fully complete the repair and reset the codes in your system, which is what causes the light to come on. You're first place to turn is them--they didn't finish the job. It may be as simple as resetting the computer.

does s430 2000 have an oil in the rear

There is a sensor you'll have to replace too. Its near the brake shoe in front of car...