Would the code light always come on for a defective brake master cylinder? on 2008 Mitsubishi Eclipse

Was told after getting an inspection of my brakes and having symptoms of high-pitch squealing and pedal going very low to floor, but they still work (just not as well as before)that the master cylinder and possibly the booster was defective and needed replacing. However, on this site I read that a code light should come on for bad master cylinder. Also, how much should it cost for a complete repair of a master cylinder and booster?

Asked by for the 2008 Mitsubishi Eclipse
Possible for an abs code to be stored if any part of the system fails.
1 more answer
Scan the code first and post so we can advise you, I myself have not seen a code for the master cylinder.