Rear motor ABS circuit (RF)?

Hello,

I have a 99 Sunfire, the ABS and Brake lights are on, codes shows the following:

C1278 RF Solenoid open or short to batt
C1125 Rear Motor ABS circuit (RF)

Could someone please check in the manual (Chilton or Haynes) what do this codes mean? and what should I do to solve them?

Thank you in advance