2018 Failed ABS HCU Teardown

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Choupique

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Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.

20230429_152409.jpg
Free brush spring

20230429_152409.jpg
Bound up brush spring

20230429_152330.jpg
Brush with contact

20230429_152315.jpg
"Brush" with no contact

20230429_152033.jpg
Motor housing

20230429_151925.jpg
Motor rotor

20230429_151116.jpg
Pump plungers
 

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Phylodog

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Thanks for the info, mine is doing the same and that makes sense. I thought it was likely a busted solder joint but perhaps not.
 
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Choupique

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You could potentially pull the motor off without removing the HCU. It's held on with only two bolts but i dont remeber if there are brake lines in the way or not. If yours has the same problem you could likely have it fixed at a starter/alternator shop.

I'd love for somebody to try it. I might bring mine by to see if it's repairable just for my own knowledge for when my next one craps out.
 

Daw14

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Thanks for the pics and write up, this may be of help for those who like to do it themselves. Thanks again.
 

Dutra

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Exact same thing happened to me. Pics look very similar lol. Same year too. Shame there is no recall on this.
 
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Choupique

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It's the same part for all the gen 4 trucks but very disproportionately affects the 2018s. There's some kind of wiring or programming difference with the 18's. We have a large fleet of these trucks and the 18's are perpetually having this failure.
 
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Choupique

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Exact same thing happened to me. Pics look very similar lol. Same year too. Shame there is no recall on this.

Your motor had the same issue with the brush being stuck in?
 

Dutra

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Yes.

 
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Choupique

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Excellent, thanks. It makes perfect sense. I'd wager that is the primary failure mode for these. Absolutely amazing that in 2023 we have ancient technology like motor brushes causing serious reliability problems

I bet a stiff spring and some Emory cloth and some dielectric grease would fix it right up.

Also, why'd they locate the thing right on top of the strut tower? That's probably the most vibrating spot on the whole damn truck.
 

DaveSharp

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Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.


Free brush spring


Bound up brush spring


Brush with contact


"Brush" with no contact


Motor housing

View attachment 520270
Motor rotor


Pump plungers
You can see it has a really bad contact pattern.
 

Pat E

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1 - You can pull just the motor off while the rest stays attached to the truck (at least on a 2018 PW). It was actually very easy to get off. I would remove the plastic cover so you can see the two bolts you will remove (the three plastic retainers have a Phillips head screw that can be removed and then they pop right out - don't force and break one like I did).

2 - It takes a little bit of prying and wiggling of the three plastic tabs on the motor housing to separate the windings from the housing, but it does come apart pretty easily.

3 - The brush that was stuck on mine was the one that was oriented down (not sure if that is a 50/50 thing or an indication of dirt going with gravity and plugging it up).

4 - I cannot figure out how to pull the shaft out from the plastic housing. If I can, it will make cleaning the brushes much easier. Currently, after an hour of carb cleaner and WD-40, the one brush is still sticking.

5 - I'll report back how it all goes back together once the brush is fixed.
 
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Choupique

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It would be excellent to find out that the motor can be repaired this way. Could save people a lot of money.

It's so frustrating that the majority of problems with these horribly expensive vehicles could be fixed without replacing whole components or subsystems if the people had the information to do it, or if the dealers had the desire to do it. Outside of windowing engine blocks and splitting transmission cases, the majority of failures can be traced back to one individual very cheap component.
 

Pat E

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So I was able to make the repair, and so far so good.

This link on another forum also has a lot of good information and photos:


Couple of things:
1 - I came across some other posts that talked about drilling through the three dents in the motor housing to get it apart. DO NOT drill these. There is no need; they are there to hold the magnets in place. With a little bit of prying on the 3 plastic tabs with a small flathead screwdriver, you will get it started. As it starts to come apart, you will need to use a bigger flathead screwdriver. You will not have to beat on it to separate the housing from the windings, but it will take some finagling.

2 - As attempting to clean out and lube my stuck brush was getting me nowhere, I finally decided to very slightly spread apart the brass body where the brush rides, and that did the trick.

3 - You can test the motor before pulling it out of the HCU body and once you have it on a bench after you have made the repair. You can test it in two ways, put 12vdc to the connections to see if it runs or check for continuity. With continuity, I was reading 1.4 ohms. For short testing, it does not matter which connection gets positive and which gets negative.

4 - Getting the motor back into the HCU body is the tricky part. Definitely review the posts in the link above. The tricky part is getting the 2 plungers/pistons inside the HCU, where the motor sits, pushed in and out of the way. This is where using modified feeler gauges is a necessity. I bought and used a pre-bent set from O'Reilly's that only cost $7, and the bend was right where it needs to be for this job. Use the two thinnest feeler gauges. Per the referenced other forum, I modified the short ends of the feeler gauges (see my attached photo) using my Dremel drill.

After taping the feeler gauges in place (see other forum again), when you push the motor in, you will feel it when the plungers/pistons get pushed in and out of the way. I gave several attempts at trying to hold the the motor in place by hand as I pulled out the feeler gauges using locking pliers. I then had an idea of using a C-clamp, which would probably also work, but in reaching for my C-clamp, I saw my one bar clamp and thought it might work better. With the ABS module removed from the HCU body, I used the clamp to hold the motor all the way in as I pulled the feeler gauges out, still using the locking pliers. This worked the first time and the feeler gauges pulled out fairly easy.

5 - You could again test the motor, once you have it bolted back together, by applying 12vdc or checking for continuity (see photo of HCU body motor connection). As I have AlfaOBD, I put the ABS module back on, reconnected the electrical plug, and then went into the ABS function in AlfaOBD and ran the "Recirculation Pump" test. This will activate the motor for about 5 seconds.

No more C0020 ABS codes, no more annoying dinging, no more flashing ABS and Traction Control icons.
 

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Choupique

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Excellent! Thanks for taking the time to write all that up. Hopefully it continues to work well for you. DIY problem solving at its finest!
 

ACJCF2

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I am on my third HCU (warranty) and second ABS controller and waiting on the updated ABS controller due in (allegedly) in June. I asked if the faulty ABS Controller was causing the HCU to fail and was told that the HD/Diesel technician said it could very well be. My question, will Chrysler replace both for a matched set? Answer, only if the HCU is bad at time of replacement. I was given the Customer Care number to plead my case. They said the replacement ABS Module will be covered under the Chrysler Extended Maintenance Plan ($200 deductible). I told the service writer that that wasn't fair. She agreed and gave me the Customer Care number to call and start a case. So will see what happens.

Jim


Repair history.
1st HCU 07/06/20 4,834 miles at Selling Dealer 75 miles away
2nd HCU 04/19-22/22 17,938 miles at local Chrysler Dealer in town (Note: Tech says may have faulty ABS module causing HBU failure)
3rd HCU 01/10-19/24 24,394 miles at selling dealer, ABS module on back order till June. To be covered under the Chrysler Extended Maintenace Plan.
 

Digman138

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Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.

View attachment 520265
Free brush spring

View attachment 520265
Bound up brush spring

View attachment 520267
Brush with contact

View attachment 520268
"Brush" with no contact

View attachment 520269
Motor housing

View attachment 520270
Motor rotor

View attachment 520271
Pump plunger
Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.

View attachment 520265
Free brush spring

View attachment 520265
Bound up brush spring

View attachment 520267
Brush with contact

View attachment 520268
"Brush" with no contact

View attachment 520269
Motor housing

View attachment 520270
Finally got around to ripping into my failed HCU today. Found the root cause for my failure. The spring behind one of the brushes is either broken or the channel is gunked up or something. When I push the rotor slightly away, it loses contact. Push it the other way and the other side brush will hold contact most of the way, but not entirely.

Someone who was inclined to do so could repair this themselves. The motor is easy to remove. The intermittent contact makes perfect sense with the dashboard disco and it's seemingly random dependency on bumps.

So, if you are tight on money and a little handy with DC electric motors or have a good starter/alternator shop nearby, this is certainly worth exploring. I totaled mine taking it apart, but it could be done more carefully and reassembled.

View attachment 520265
Free brush spring

View attachment 520265
Bound up brush spring

View attachment 520267
Brush with contact

View attachment 520268
"Brush" with no contact

View attachment 520269
Motor housing

View attachment 520270
Motor rotor

View attachment 520271
Pump plungers

Motor rotor

View attachment 520271
Pump plungers
Thanks for the Information. It worked like a charm!! No more BINGING.
 

Roll Tide Ram

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I waited until this week to take my 18 in for this problem. I was hoping they would be caught up on fixing them. I am in line for a replacement because they are still on back order. The extended warranty is supposed to cove this.
 

bigramma0786

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Does anyone know if this will solve code C2200 (ABS Module Failure)? This is for a 2014, however.

I just purchased a used control unit w/ pump off of ebay and from earlier research I was only going to replace and AlfaOBD reinitiate the control unit. I'm now wondering if I should investigate the motor first.
 

Roll Tide Ram

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Maybe mine is fixed. New part put on yesterday. Time will tell. But a new can of worms was found. Asked if they could identify an oil drip for me. Timing cover gasket . Somehow the warranty I bought covers everything but the engine. Quoted roughly 5k to fix it.
 
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