I have a 95 Z M-6. Just lately the ABS INOP comes on and stays on. Today while in traffic my LOW TRAC light came on and my brake pedal went to the floor with no brake pressure or operation. This all happened in a split second. The brakes are working fine with the ABS/INOP on. But when the LOW TRAC comes on the brake pedal goes to the floor. Brake fluid is full. Any help will be appreciated. Thanks

 

I'd like an answer to this as well, as I think the same thing just happened to mine...

I just left work, was slowing to a red light and all of a sudden, pedal got mushy and went to the floor and the caliper seemed to release. ABS INOP and LOW TRAC came on. Luckily the caliper grabbed again right before I rear-ended the dude in front of me.

Fluid level was good, all pads and rotors changed about 5k miles ago, fully bled with new fluid, no air in the lines, just seemed like ABS thought a wheel was locked when it wasn't.

 

ABS INOP light has been haunting me during every cold season.
This time i had to lockup my wheels on the highway ruining both my front tires! all because ABS wasnt working.

I've checked/cleaned every abs connection and all 3 sensors, short of paying the dealership $120 to scan my ABS codes. From what I gather on other forums it can be a bad ABS VALVE MODULATOR, the black box on the side of the aluminum abs valves onder the hood. NOT the abs box under the passenger dash.

MY questions is....if i replace this part (acdelco 18024454) is DOT3 going to pour all over the place once the torx screws are removed? I've read that without the "special" gm tool, your average garage mechanic cannot blead the ABS valves. I do not want to have to bleed anything. true???

 

The photo is the abs motor pack; you do have to remove the whole abs unit to replace so you will need to undo brake pipes and some fluid will come out. You will need to bleed and you will need a Gm tech 1/1a to rehome the abs pistons if you replace the motor pack. Abs modulator, combination valve, motor pack, ebcm are all fairly expensive even for reman parts ($100+ each) so part replacing without scanning can get exspensive.

I am not aware of any abs system failure that will cause "pedal to the floor" other than a fluid problem (low, air, dirty, leak); when a componet of the abs system fails, the brakes will still function only without abs. Posts said "fully bled" but a common error is failure to bleed the abs unit itself; there are two bleed screws on the front of the abs tucked under the air intake. Also when bleeding these abs units without the tech 1/1a use a power bleeder as using the pedal without ign on (power to ebcm) can cause the abs pistons to lose home position and then you will need the tech tool to rehome. If you have "de-homed" the pistons by driving with the abs unbled, there are some that allege a number of rapid hard stops for 20+ mph foloowed by re-bleeding can get the air out; I do not know if it works or not.