2001 24v cummins. I started having this problem a couple weeks ago. I've changed both speed sensors. I've pulled rear diff cover and checked tone ring. I had batteries checked and had one bad one so I changed them both. I've checked ac voltage from alternator. does anyone have any ideas on what to check?

Is your alternator putting out? Your gauge is only reading battery voltage and not charge voltage.

Yes. I had unhooked it when I made this video to see if it made a difference 

Have you checked for any trouble codes?

It might be your ABS Module.

 

https://www.moparpartsgiant.com/parts/mopar-module-anti-lock-brakes~5015528ad.html

I wondered about abs module. Are they vehicle specific?  This truck has the 2 wheel abs

Theres no codes showing. Is there a way to check abs module?

No WTS light 

It had already been running a while and was warm. Wts light works

10 minutes ago, Royal Squire said:

No WTS light 

Ignition not off long enough maybe?

Could it be because you’re out of washer fluid?

I wish it was that simple...lol

Has anyone had trouble with their abs module?  What are the symptoms? 

@Mopar1973Man had to have his repaired a couple years back by a company in Idaho, Module Masters I believe it was. But I do not remember the symptoms.

Yeah I saw that on here somewhere. Trying to figure out how to diagnose it and be sure before paying $130 to have it rebuilt

Yep. Figured I would tag @Mopar1973Man and get his input.

I believe some higher end code readers(snap on, DRBIII, etc) can read abs codes

13 hours ago, William Smith said:

Has anyone had trouble with their abs module?  What are the symptoms? 

 

Mine started out doing what yours does. It first started out acting up when I was towing  heavy on a hot day and climbing long grades. It was related to hot under hood temps. After I topped out and cruised on the level it would work fine again, until the next hill.

 

At first I thought it was the rear axle sensor, that climbing, it raised the temp and then cooled off on the level. So I changed it, no help at all. I don't remember how I determined it was the module, I think I guessed Anyway, I bought a used one off E-Bay and it fixed the issue, that was several years ago. It is vehicle and 2 or 4 wheel abs specific.

 

It did act up one time this year. I was towing heavy out of Phoenix this past summer @ 115*. The long grade out of Superior, 5 miles of 7%, water temp at 219, it quit for a bit, but just this one time.  

Edited October 16, 20196 yr by NIsaacs

I've had abs/brake light come on when hot out or if I drove for a while for few years now like 5-6 Mabel more. I'm starting to think it all began when I had surging problem, like engine would start cutting out on steady speeds on hwy 65 or so. Though it was vp, but thanks to good people here I got talked out of changing it. Between new injectors and rebuilding alternator, surging went away. I'm thinking it had time to damage abs module. I have a spear one I'm going to put on and try. I also changed rear sensor and front sensors, then front hubs with new sensors again, same issue. Using snap on, it's saying front left sensor is randomly dropping signal. Having hard time believing that both old and new wheel bearings are junk. Last month I went to Canada Trip fishing and back, every time we filled up with fuel I check temperature and they were cool, even to the touch. So next step for me is ABS module if it doesn't fix it I'll be changing front left bearing again.

Btw driving truck to work today didn't set abs/brake light on, it's 35f out, if it was summer temps I'd have it come within minutes of leaving. It's 70 miles one way. 

Hope you figure out your issue. Let us know. 

Verify that the wiring going from the abs to the rear diff is good. 

 

I used a paper clip to jump the rear sensor plug, then used a multimeter to ohm from the ABS.   I was getting high resistence.

 

In my case the issue was the junction behind the front drivers tire.   It is tucked up in that area and can get beat up with road stuff causing the wiring to degrade.  

@Mopar1973Man had an ABS problem.  He changed sensors and wheel bearings with no luck.  He found the left front wheel tone ring bad/loose.  

Unit bearing the tone ring failed in the unit bearing. After replacing both bearings ABS went off.