Low brake pedal, ABS bleeding, ABS Module diagnostics

I have been chasing down a low hard brake pedal for several weeks
I have thrown enough parts at it and am still at square one
2013 Dodge Journey SXT AWD 4 Wheel Disc ABS V6
Low hard pedal about an inch off the floor
Right rear caliper with a frozen parking brake lever, ebrake cables fine
New rear calipers, rotors, pads, hardware
Gravity bleed, calipers only bleed, manual bleed, vacuum bleed, one man bleed, ABS Bleed (right side only, Autel maxi ap200c will not go to the left side, waiting on Autel customer service for over three weeks)
Plugged master cylinder outlets high hard pedal
With the front brake line attached to the master cylinder and the rear port plugged low pedal
With the rear brake line attached to the master and the front port plugged high hard pedal
Replaced the master cylinder no improvement
Off to the dealership for diagnosing they bled the service brake and the ABS four times charged me nine hundred and told me they did not have a definitive answer. Wants to replace the ABS with no guarantee of success
Dodge back to me
I replaced the Hydraulic Control Unit of the ABS
Gravity bleed, manual bleed, vacuum, bleed, one man bleed, reverse bleed, ABS bleed (right side only, still waiting on Autel)
Some improvement Pedal is now two inches from the floor instead of one inch.
Now looking into the ABS CONTROL MODULE
CODES
Low voltage (new battery eight year old original Mopar)
C006A49 pitch yaw sensor (All 4 wheels up on stands turning front wheels to bleed) code erased has not returned
Um000288 can c bus performance off (my son was checking fuses, voltage, relays, ..) code erase not returned
C10822F vac sensor signal erratic
This one might be the winner
When the ABS bleed quits after the right rear wheel and it is time to move to the left side the Autel unit gives me a “evac and fill procedure not performed
Autel has no answers, dealer said ABS bleed worked flawlessly, can’t find any vacuum leaks, erased code, it did return once but not since.
Road test shows all ABS on all 4 wheels functioning
Any abs all help will be greatly appreciated

You might have to pressure bleed it. And crack open the bleeders while the pressure bleeder is going

Got confusing but maybe try pinching all 4 caliper hoses off then release one at a time until it becomes a low pedal. Then replace that caliper

Are you getting fluid out of all of bleeders when you're bleeding it? Does it go to the floor with the van running and off? I don't think these have an accumulator, do they? Did the master run dry at some point? Maybe try bleeding the four lines at the actuator? I crack them all, pedal down, close all, then do one at a time.

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Have a Motive power bleeder ordered but don’t think it will make a difference. That is the recommended procedure on alldata.
“ When bleeding the brake system, some air may be trapped in the brake lines far upstream, as much as ten feet from the bleeder screw. Therefore, it is essential to have a fast flow of a large volume of brake fluid when bleeding the brakes to ensure all the air gets out.”
Don’t think it will do much tho. I have run 2 gallons of brake fluid out since the dealer bled the base system and the ABS.
When I bled the ABS the fluid being pumped out by the ABS HCU was about half the flow and pressure of what I could do just pumping the brake pedal. No different than the original HCU I replaced

Early in this process I did pinch off all four flex lines and still had a low pedal. I am wondering how I could plumb the ABS out of the system.

Tutti57 wrote: Are you getting fluid out of all of bleeders when you're bleeding it? Does it go to the floor with the van running and off? I don't think these have an accumulator, do they? Did the master run dry at some point? Maybe try bleeding the four lines at the actuator? I crack them all, pedal down, close all, then do one at a time.
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I have put two gallons of brake fluid thru the system using gravity, pumping, vacuum, and the one man bleed system since I replaced the master cylinder and the HCU.
Like the one man system using the pop bottle with a hose running thru the lid with a vent hole. I use that yellow greenish fuel line that you see on small engine tools. 3/16 ID fits tightly on the bleeder and into the bottle. Had to use the same fuel line to make a seal so that air could not be sucked in thru the bleeder’s threads. Touched up with with a lil dpte pipe sealer.
Can pump the pedal twelve times with the bleeder open one full turn before I have to refill the master. I was getting full flow doing this. Used a liter pop bottle as it will fill up quickly

The pedal is high and hard with the engine off but It will sink to 2 inches from the floor the minute the booster gets vacuum..
An accumulator is referenced in the ABS unit but there is no bleeder. Cracking the lines at the ABS/accumulator/actuator reminds me of my youth. Bleeding a master cylinder by cracking the lines open under pressure. Was a little messy but quick.
Will give it a try at the ABS.

Autel’s customer service rep promised me an answer Monday on why their scanner will only actuate the right side of the vehicle. I asked him to send me a scanner that would work if his engineers can’t figure out why the one I have will only do half the job.

Leaking union ---- takes only a tiny leak and what happens is air gets drawn back into the system when pedal is released.
With engine running you need to get an assistant to put hard pressure on the and go roand the pipe.und every single union and pipe with torch looking for any sign of dampness between the brake union and the pipe.
The other thing check every caliper is sliding freely and the pads aren't wearing tapered.

Thank you all
Sound advice from all
Went back to basics
Checked every caliper flex line junction fitting
Some good news checked the master went to crack open the the primary and secondary lines only to find an ever so slight leak at the rear of the primary
Plugged both ports solid pedal
Reinstalled the lines with a little Teflon paste on the threads no leak
Moved over to the HCU cracked open each wheel line
Poor pressure/flow from the left front
Thinking about pushing a bunch of fluid thru it With the line off to see what will us out
Thanks again all
I was so sure it was a computer issue but

Did you bench bleed the master cylinder with the plugs provided in box till pushing in rod became hard ?

This step needs done if you have not done it

I used a cardone master cylinder tool
Plugged both ports then filled them one at a time. Afterwards with both filled and plugged I could not push the rod in at all.
Hope to have this done on Sunday.
Will let you know. Thanks

Is there a slider, pad, or piston seized somewhere in the mix? Upsidedown caliper? This is sounding very much like one that I chased my tail on a few weeks ago. Thought everything was moving free, pedal nearly to the floor, no leaks, bled all corners and took a while to get any flow out if front lleft. Ended up being a stuck slider.

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The rear calipers have been replaced adjusted and bled
The front calipers have not been checked since the pad swap last year
I will pull them for a closer look
Thanks

As someone has already mentioned, try isolating the low pedal problem to a specific wheel when by clamping off the line. Google Raybestos Technical Service Bulletin 18-15 for details.

If the results of the above test lead you up stream as the source of the low pedal condition, I have resorted to blocking off MC and /or ABS lines at HCU to isolate the problem using the Thexton 803P Master Cylinder plug kit

Another cause of low pedal I have seen is when someone replaces the brake booster without adjusting/verifying that the brake booster push rod is properly adjusted and there is too much space between the rod and MC plunger . Over
adjustment can cause the brakes to lock up if not enough space. (I don't think rod adjustment is your problem, based on some isolation tests you have performed at the M/C}
HTH

Hey Nelson60
I am also assuming the booster and rod are good With the MC plugged I have a high solid pedal with the engine on.
I really don’t understand why I can have a high solid pedal until I start the engine. The pedal then sinks to about 1 to 2 inches from the floor

Well it has been forever and still no improvement can’t find any leaks, seeps, bad hoses, bad calipers, etc
Tried manual bleed, vacuum bleed, one man bleed, pressure bleed, all to no avail
Do have the cleanest dot 3 in town tho
I wondered about a bad proportioning valve effecting the bleeding
According to my info that function is computer controlled through the HCU
I am assuming that without power this would not function or effect the bleed..
I am ready to deviate from the factory bleed sequence just in hope
I am also considering making the master the highest point by raising the vehicle and then lowering the vehicle in sequence
Also thinking about bypassing the ABS and traction control all together as a last resort
Here’s to hoping.

Did you ever check the front pins anqd piston to see if they are stuck?

Is there a specific sequence that has to be done for bleeding each corner? I've notice with nissans that it is often not working furthest to closest to the MC. Sometimes it is, but it could also be a diagonal progression.



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Front calipers are dual piston everything seems proper
The bleed sequence is right rear, left front, left rear, and then right front.
That is why I am wondering
Furthest to closest to the master would be right rear, left rear, left front ( brake lines goes from the master to the HCU tucked inside the right front fender), then finally the right front.
Currently I am pulling vacuum on the master cylinder reservoir using the cap and hose from the pressure bleeder hooked up to a valve then the vacuum pump.
Hope to see something change.
Then it will be back to pressure bleed then ABS bleed then pressure bleed,

With all the DOT3 you have purchased, there is now a shortage in our local store.....LOL
This sounds more like an internal problem in the HCU. Maybe the one you installed (used) is/was defective?
Have you blocked/plugged off the ABS HCU 100% to rule this out as the culprit?
Did this problem suddenly appear after doing the brake job or was it suffering from a low pedal condition that was initially thought to be due to brake pads needing replacement, etc?

A very late update!
Final resolution. I bled the lines to and from the ABS unit by cracking the line fitting while the brake pedal was applied. Got some goo coming out of a few of the fittings. Pulled vacuum on the master cylinder. Let it hold vacuum overnight.

Still low pedal. RRRRR,

Buttoned it all up and went for a test drive. Amazingly the pedal came up and became rock solid!

Thanks to all the replies and help.