D45

The brake and ABS warning light came on a few days ago, stayed on for a few seconds, and then went off.

Today, about once every few minutes the brake/ABS lights will come on and turn off.

Using the 3 cycle key on/key off test, there are not any fault codes stored.

Also, ocassionally while slowing down, at 5-7 MPH, it feels like ABS is kicking on.

Any ideas, suggestions, or info?

CatDiesel_762

Your wheel bearings would be my first guess. I would check you wheel bearings for excessive play. Take a good long look at your front ones in the hub area. Its been noted on these boards that the ABS and Brake light come on just before the wheel bearings let go. Normally, it happens right afterwards of the lights coming on at highway speeds. Do a search on fronts hubs or wheel bearings for our third Gen Rams to find more information regarding this diagnostic. Yeah, they tend not to throw any codes until the part falls off.


Another guess would be your brakes or ABS sensors need service. Check the wiring going to the ABS sensors on all four corners. Look for pulled, frayed, or even rub through the full length of of the wire all the way from the sensor to the ABS computer or the Truck's ECM. Check your brakes for worn pads as they might be due for a change.

Shawn

BlackPuff_Gone

A shot in the dark here. I have 97 Grand Cherokee that had the same problem. First time I put pads on it, it took the sensors out and inspected them. One of them had a weld spatter on the face of the sensor. I removed it very carefully with a razor blade and some coaxing. Haven't had a problem since.

Not sure DRs have same setup.

V/R

redryder64

Actually it's more likely your rear speed sensor... mine started it a few days ago after driving in deep water for an extended period of time...

It's located on the top of the rear differential and has a plug to it. You can check the plug for good connection and/or maybe a loose wire...

It's easy to replace and is about a 30-40 dollar part. you just unplug it and take the bolts out, pry gently all around the edges, and it will pop right out... new part goes in just about the same way... I had to use a small block of wood and a rubber mallet and "tap" on it gently. Replace the bolt and plug it in and off you go!

There are one on each of the front wheels but they hardly ever go bad... always the rear one.

That would be the first thing I would check!

Hope that helps.

D45

Is the rear sensor a dealer only part?

Is there any way to test it before replacing it?

Why am I feeling the ABS kick on at 5-7 mph?

D45

Also, will I need to reset the PCM and clear the brake/abs light?

vzdude

The abs lights will reset themselves after repairs. I would be betting on a front hub or sensor as well. The rear sensor usually just goes, not usually an intermittent thing. Can you tell which wheel is activating on the ABS? Usually you can feel the truck pull to the opposite side. ABS actually releases the brake that the ABS module thinks is locking up. Have someone with a scanner look at the ABS sensors while you drive. Duplicate the 5-7 mph ABS activation, and they should be able to see which sensor goes to 0 first. That will be your trouble area.

redryder64

D45-

As far as I know it's a dealer part and I'm not sure of a way to test it... I just replace it!

And when mine started to go both times it was intermittent for the first few days and then just activates when I start the truck... when I stop my speedometer needle bounces and then comes to rest... I think that's why the ABS activates because the truck is getting conflicting reports since the sensor is not functioning properly.

vzdude

Yes, it could be the rear sensor too, but with no comment about the speedo issue, I would still assume one of the front sensors or wheel bearings.

CatDiesel_762

I have to agree with VZdude and say it is in the hub or wheel bearings. The sound of a ABS going off at low speeds such as 5-7 MPH could be the sounds wheel bearings going south too.

Or because it is inter-mitten, the problem may-be like a electrical connection or break in the wiring. That is why I said to look at all four corners and follow the wires back to the ECM. Wiring that has worn insulation and is grounding out tends to give inter-mitten faults. This can make it hard to chase down, due to a lot of signal wires being piggy-back onto other sensors. Out trucks have wires that have basic insulation expose to the elements and sharp sheet metal edges, so it is possible that the wiring may be at fault. However, I am leaning towards wheel hubs or bearings due to his signature showing the that he has oversize tires and coil spacers on the suspension. Just read the post in the Engine and Drive-trains section regarding the front bearing failure and you will see a pattern of bearings going out earlier than trucks left stock due to oversize tires and suspension mods.

As for clearing codes normally the ECM will clear the code after the third starts cycle that shows no further set codes. Otherwise, go to your local part store and ask them to hook up their cheep OBD II scanner and look for any codes in history that are not active. Since the only codes that show with the three key cycle trick are the known active codes. They can might even clear your codes for you too.

Shawn

D45

For $35 I am going to try replacing the rear ABS speed sensor and hope it works.

The front hub bearings appear to be very tight........

vzdude

Save your money D45......where are you located? Maybe I could hook my scanner up for ya.....at least you'd know for sure which sensor it is.......

vzdude

I know some of them just had an issue with rust build up under the sensor causing the sensor to lift and make the airgap too big. You can pull the front sensors and sand down the surface that they bolt into and see if it cures it. I've done that several times too.

D45

NW part of the state...........

vzdude

PM sent.

dangmessagetooshorterror!