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

[Spindrifter]

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 . Anyone that does the bleed and flush please report back.

 

[Choupique]

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]

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.

 

[Spindrifter]

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]

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

Fingers crossed.....

 

[Choupique]

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]

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
Ram Cares

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

 

[Jeepwalker]

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 .

 

[Choupique]

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]

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.