Air Brake Antilock Control Unit/module problems of the 1998 Oldsmobile Intrigue

The "antilock" and "brake" light came con while driving. I noticed some change in braking and immedixately went to ge it checke out. The mechanic said it was a computer component that controlled the rear braking system and that it was common for the Intrigue. I then went to my mechanic who maintains my vehicle on a regular basis and he ran a computer diagnostic on my car and also said it was the computer and the motor that operates the rear brakes. This problem is not a normal wear and tear problem for cars and has endangered me and alsois very costly. Both mechanics estamate to repalce the entire system would run about $1700 and there is no way around it. I am cuurently using only my front brakes and if I would have not known to get them checked shorly after replacing both my front rotors and pads the problem would still have gone undetected.