Brakes worked fine until now.

I will attach a procedure for the bleeding but you need a scan tool that can access the ABS system. Also, there can be no fault codes in the system or the procedure will not work.

Gravity and vacuum bleeding procedures are not recommended for use with the anti-lock brake system. The two person (manual) bleed procedure is the preferred method, although pressure bleeding is also possible. Do not pump the brake pedal during the bleeding process, as fluid aeration may occur.

1. Install pressure bleeder using equipment manufacturer's instructions.
2. On models equipped with metering portion of combination valve, remove combination valve dust caps and install valve depressing tool No. J-39177, or equivalent, on valve end.
3. Bleed all four wheel hydraulic circuits. Bleed righthand rear wheel first, followed by lefthand rear, righthand front and, finally, lefthand front.
Leave bleed screws open until one pint of fluid has been bled out of each wheel.
4. After all wheel hydraulic circuits have been bled, remove combination valve clip, then connect scan tool to diagnostic connector.
5. With brake pedal firmly applied, run four scan tool "Functional Tests, " then repeat preceding steps.
6. Ensure brake pedal feels firm; re-bleed wheels as many times as necessary to achieve proper pedal feel. It is likely that two to three quarts of brake fluid will be necessary to complete a thorough bleed procedure.