Potential fix for the dreaded "Service ABS system" "Service Electronic Braking System" messages

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Dginn69

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Yep, I just pressed the pedal when it instructed and it would pulse then go to the floor. I did it on each wheel, then cleared the codes, and disconnected the computer. Restarted the truck and no codes or warnings. Still riding good so far…
This is where my confusion is coming in. "I just pressed the pedal when it instructed and it would pulse then go to the floor." What is "it"? And how does "it" give intructions? Thank in advance.
 

Choupique

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Yep, I just pressed the pedal when it instructed and it would pulse then go to the floor. I did it on each wheel, then cleared the codes, and disconnected the computer. Restarted the truck and no codes or warnings. Still riding good so far…

There's a difference here between yours and mine. Mine never asked to open any bleeds. Maybe mine didnt actually replicate what yours did. Do you have a bypass harness for yours or anything like that?
 
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Spindrifter

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This is where my confusion is coming in. "I just pressed the pedal when it instructed and it would pulse then go to the floor." What is "it"? And how does "it" give intructions? Thank in advance.
AlphaOBD software. I have it loaded on my laptop that I had connected to the truck with the OBD Link EX cable and security harness for 2018+ trucks. When I ran the "Bleed ABS" function it prompts you to press the pedal etc.
 
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Spindrifter

Spindrifter

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There's a difference here between yours and mine. Mine never asked to open any bleeds. Maybe mine didnt actually replicate what yours did. Do you have a bypass harness for yours or anything like

There's a difference here between yours and mine. Mine never asked to open any bleeds. Maybe mine didnt actually replicate what yours did. Do you have a bypass harness for yours or anything like that?
Yes, I have the security harness for 2018+ Rams. It wouldn't work at all for me without the security cable and the OBD Line Ex cable.
 

Dginn69

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AlphaOBD software. I have it loaded on my laptop that I had connected to the truck with the OBD Link EX cable and security harness for 2018+ trucks. When I ran the "Bleed ABS" function it prompts you to press the pedal etc.
Ah, ok. I was considering getting alpha obd. Thank you.
 

James Winkelman

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I have seen mention in this thread about doing a complete flush and abs flush...curious if anyone with the intermittent abs issue has had the intermittent light issue resolved with the flushing?
Also, with the national backorder of the hcu does anyone know of a company that will rebuild the unit? I have contacted a few companies but no luck in finding a company that will rebuild.
 

Sherman Bird

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Great tip...

I wonder if there could have been a stuck solenoid, a cold solder joint or bad wire connection which was vibrated 'good' by the slight movement of the pump and/or valves as it went through the bleeding process? Hmmmm...

Thanks for sharing.
Cracked solder joints seem to be the norm today, as opposed to cold joints. This is due to the lead being removed from solder. I wonder if there is a point of overkill as to removal of lead from EVERY thing!?
 

RamCares

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We see that you have received some great advice from your fellow forum members! However, if these suggestions do not address your concern and you decide to visit your dealer, our team would be happy to offer additional assistance throughout that process! We're available via private message.

Callie
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Jeepwalker

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As brake fluid ages, takes on moisture, is heat-stressed, it's pH drops ...meaning the brake tube's internal environment moves further away from the metals' (and rubber) "Safe" range is, the more corrosion can/will occur. To what extent this affects the ABS valves, I can't say. It would probably have to sit a long time to seize. But maybe actuating them through a bleed process made a difference. Or the vibration of the process made a weak electrical connection 'good' again.

Most of what I've seen online are weak or cracked solder joints on modules ...by looking at online 'fixes'.

Regardless, it's important to replace the fluid every so often to maintain an internal higher pH range where the metals/rubber components are 'happy' and help avoid corrosion.

Edit: (Pretty much the same is true for coolant)
 
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Spindrifter

Spindrifter

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I have seen mention in this thread about doing a complete flush and abs flush...curious if anyone with the intermittent abs issue has had the intermittent light issue resolved with the flushing?
Also, with the national backorder of the hcu does anyone know of a company that will rebuild the unit? I have contacted a few companies but no luck in finding a company that will rebuild.
I might just go ahead and do a real bleed and flush to have piece of mind that moisture in the fluid might cause future issues. I'm hesitant to mess with anything since I'm still running with no codes or warnings though :oops:. Anyone that does the bleed and flush please report back.
 

Choupique

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I'm waiting for bypass harness to come in. Once I have that and do a mock bleed I'll report back. It'd be a downright miracle if this works as a bandaid
 

Jeepwalker

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Another method to achieve a 'mock-bleed' is by driving down a country road, putting the Rt tires (only) on the gravel, then slam and hold down the brakes HARD. Hold while the ABS pump is acuating. Repeat the process for the L. side wheels. This requires the truck to have at least a semi-firm pedal. If the ABS pump doesn't activate, there are other issues.
 
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Spindrifter

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I did a complete fluid flush over the weekend. I did another ABS bleed, then a standard brake bleed until I ran 2 bottles of fluid through the system. Then I did a final ABS bleed and topped off the master cylinder. I just wanted completely new fluid through the whole system to make sure moisture or old fluid was taken out of the equation. Still, running good with no lights or warnings.
 

Jeepwalker

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Good job (small bottles, or big bottles?).

Fingers crossed.....
 

Choupique

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Update on mine -

Installed bypass harness and did "mock bleed." Was instructed to open right side front and back bleeders. Had instant recurring faults on test drive. Did mock bleed again, no faults on next test drive. ~ 30 miles. I've had this happen before so not getting excited, but it certainly does affect something by doing a mock bleed.
 

Billy 150

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We see that you have received some great advice from your fellow forum members! However, if these suggestions do not address your concern and you decide to visit your dealer, our team would be happy to offer additional assistance throughout that process! We're available via private message.

Callie
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Ram Cares, what is Ram doing about this problem of no part availability for your customers?
 

Jeepwalker

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Probably:
1) Frees up 'stuck' valves (but I doubt it)
2) The vibration caused during the bleed process and repeatedly operating the pump, 'wiggles' or 'vibrates' the module connector or internal board, such that a bad hairline solder crack makes 'good' ...but for a while.

Considering how common bad solder joints are on ABS modules, my money is on #2. There's a bunch of youtube videos on them in general (I don't think Ram specifically). Not an uncommon thing. A crafty person with a magnafying glass and soldering iron may well be able to repair their module in the time it takes to read two weeks worth of "Bad ABS Module" threads :D .
 

Choupique

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Update- mine is back going nuts again after ~ 115 miles. Broke down and ordered a new -AA revision HCU because I'm tired of messing with this. The -AB revision part have no availability to order from anywhere there I could find. Once I get mine replaced I'll rip the bad HCU apart and see if I can ID a root cause.
 

Cuda Tom

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I also have a 2018 Ram 2500 that has gone down this hole. Truck only has 10,815 miles. Had to the dealer and they diagnosed that it needed the ABS control module. They ordered and replaced it. Well they were wrong. After some discussion they decided to "Good Will" me the module replacement and advised that the needed Hydraulic Control Unit wouldn't be available to order until mid August.
One question is in the AA vs. AB part numbers. Is the 68143491AB they told me about the latest part that I should be looking for? Seems the only ones I find online at the AA units. I'm willing to by the unit to get this resolved as I have two trips planned and the cycling of the lights and dinging is driving me nuts, besides the possible operation of the brake system itself. Thanks for any input.
 
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