2018 RAM Service ABS Intermittent Light

[whiteram93]

I am getting the intermittent “Service ABS system” and “ Service electronic braking system” on my display.

I have had this issue before, and the dealership replaced the HCU, and all has been good for the past 40k miles or so.

I think is likely the HCU again since they are problematic on the 2018-year model.

The last time this happened, my truck was under warranty and not deleted/tuned.

A few questions I have:

Has RAM developed a better part that will not cause this issue again?

I am still unsure what I can and cannot unplug to run the truck with the MM3.

If I take it to the dealership and get them to run a complete system scan to diagnose this issue, and they unplug the MM3 from the OBD plug, what should I ensure they do or do not do so that nothing gets messed up?

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[AK Bob]

You must complete a system scan to see what trouble codes are present.

Your MM3 will only scan the PCM, so you will need a good scan tool capable of scanning all modules.

AlfaOBD software and Bluetooth Dongle paired with an Android device or Windows laptop are other options for around $200.

If you have the dealership diagnose and scan for codes, unplug your MM3 monitor and remove it from the truck.

Tell the dealership you don’t want them to flash your PCM.

If they do, you must plug the MM3 into the truck and re-flash your tunes.

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[Dodger]

I have the same issue on my 18.

Although I would never recommend anyone do it, I pulled the ABS fuse.

No more dinging and chiming now.

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[AK Bob]

If the problem is with the ABS system, there is a newer P/N for the HCU ending in AB, not AA. See the threads below for more information.

https://www.igotacummins.com/threads...ule-Controller

https://www.igotacummins.com/threads...ed-ABS-Service

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[whiteram93]

Yesterday, I took my truck to a local shop, and they read the code.

Code: C0020-01 ABS pump motor control electrical failure.

The shop said I should take it to the dealership to get this addressed, so if I go that route, I will remove the MM3 and tell the dealership I don't want them to flash the PCM like AK Bob suggested and hope they do not mess anything up.

I might try this also, but I wonder how long that fix will last.

I don't want to get this replaced at the dealership, and it happens again because the part seems naturally faulty.

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[watersupply189]

Yesterday, I took my truck to a local shop, and they read the code.

Code: C0020-01 ABS pump motor control electrical failure.

The shop said I should take it to the dealership to get this addressed, so if I go that route, I will remove the MM3 and tell the dealership I don't want them to flash the PCM like AK Bob suggested and hope they do not mess anything up.

I might try this also, but I wonder how long that fix will last.

I don't want to get this replaced at the dealership, and it happens again because the part seems naturally faulty.

If they happen to flash the truck, reflash your tune back into the truck before leaving the dealership.


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[Aristuccia]

If a dealer flashes a truck back to the factory tune, can they use the new programming from 22+?

Is it locking the PCM and rendering it useless?

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[watersupply189]

If a dealer flashes a truck back to the factory tune, can they use the new programming from 22+?

Is it locking the PCM and rendering it useless?

I haven’t heard of that happening.


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[whiteram93]

I wanted to give an update.

I followed what was done in this post and removed the ABS motor that is attached to the HCU.

Sure enough, one of the brushes was sticking, so I disassembled the brush block, sanded it to free it up, and reinstalled everything.

I have driven a few hundred miles now, and I am no longer getting the intermittent “Service ABS” and “ Service electronic braking system” messages on my display.

Hopefully, it doesn't come back again.

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[AK Bob]

I wanted to give an update.

I followed what was done in this post and removed the ABS motor that is attached to the HCU.

Sure enough, one of the brushes was sticking, so I disassembled the brush block, sanded it to free it up, and reinstalled everything.

I have driven a few hundred miles now, and I am no longer getting the intermittent “Service ABS” and “ Service electronic braking system” messages on my display.

Hopefully, it doesn't come back again.

Thanks for the update, pleased to hear you found the problem and fixed it.

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