My question first, then my story:

Using a scan tool (XTool D7), there is a diagnostic test within the ABS window: Inlet Valve Left Front (Normally Open) and Inlet Valve Right Front (Normally Open). Across the bottom of that screen is % activation buttons and when I select 100% on either, the left or the right, my brakes totally firm up. Selecting the rear does not fix my problem. Do you have any clue what that means? I'm really struggling to find any meaningfulreference.

I have a 2012 Dodge Grand Caravan, the brake pedal got very mushy after a panic brake incident. Immediately after which the red brake light came on. The light went off before I got home, assuming that it reset itself after pressure rebuilt. If the ABS light came on it didn’t stay on, but I’m sure it kicked in. I was due for front pads so I replaced the pads, rotors and upgraded to stainless lines, but after bleeding all 4 brakes they were still mushy. I double checked the check valve which did not seem to be leaking, but I did replace some brake vacuum line hoses that showed cracks, still no luck. I have yet to do the ABS bleed procedure, headed to do that now, but before I replace a master cylinder or ABS pump I noticed the actuation test and started playing with the scanner. Lots of tests available, and hunting and pecking my way thru it, there is an actuation test that solves the problem, but I don’t have a meaningful cross reference on what part that test points to.

Any help would be appreciated.

 

The abs system is an add on to the hydraulic braking system . Meaning they work independently to each other.
Most people in there cars life never use the abs system. If you are having a spongy pedal under normal usage it will be in the normal braking system and nothing to do with the ABS.
The red brake lite coming on is an indicator of low brake fluid. DId you see how low your fluid was before the front pads and rotors were changed? What is your procedure for bleeding brakes you used?

 

I concluded the ABS activated on my panic braking based on the pulsating feel in the petal and a hum it made. 1) The brake fluid was low, but not low enough where it would have felt that spongy (nearly, bottoms out). Mind you they worked fine prior to my getting cut off. 2) I initially bled the front brakes with a vacuum pump (one man job). The fluid that came out was nasty (root beer color). I used the pump to flush the system making sure never to let the brake fluid reservoir get low. I waited until I got clean fluid out of both sides. Still felt spongy so I got help and bled them traditionally. We did the front and then the back to get the rest of the nasty fluid out of the system. I DID NOT USE Any special sequence. Had I done all 4 brakes I would have started from the farthest first, but have since learned that isn't the sequence Dodge suggests. If I remember right its RR, DF, RF DR, When I get help again I'll bleed the ABS that uses that sequence or the sequence the scanner tells me to.

I'm still curious what that activation test does and why does it solve the problem. The brakes feel very firm with the 100% selected.

 

You feel the brake pedal stiffen up because the ABS pump is applying pressure to the brake fluid.
You used a vacuum pump or a pressure pump? the pressure pump pushes fluid from the master cylinder threw the lines and out the bleeder screw around 10 to 15 psi. Faster then a vac pump will suck the fluid out. Plus the pressure pump will not allow air to enter the system because its always putting new fluid into the system. Check the link out you will see what I use

Amazon

Amazon

 

The positive pressure brake bleed kit seems like a much better scheme than a vacuum that sucks air in from bleed screws, etc. I want to double back on what you said about the brake light. I may have been hasty in my reply (sorry). If the light in activated by low brake fluid, than I should trust that is what happened. If that means it was low enough to suck in air or just below a threshold prior to "sucking in air"?? But if it did suck in air, is the protocol to bench bleed the master?

 

Just a good bleeding of the system is whats needed