soft brake pedal,need help!!!

[BLK-DTH]

all of the sudden my brake pedal gets soft.check fluid and theres plenty.idiot light comes on and off.tried to blead brakes to no avail.i know if powermaster fails the pedal gets super hard.its like somethings not telling the powermaster to pump.checked fuses and everything is ok.what could it be??

 

[Nick Micale]

Only 2 reasons for a "soft" pedal, air in the system or a bad master cylinder.

Powermaster has 2 separate systems, hydraulic brakes and hydraulic assist. The "idiot" brake light functions for various malfunctions on either side.

When a "conventional" brake system has a master cyl problem, a brake light flashes.