2nd Gen Non-Engine/Transmission '02 ABS&Brake lights on dash

[ichoplin]

Hey guys, I've got the very common ABS and Brake lights lit on my dash in my 02 3500 4wd. I've been searching for a while, but felt I needed to start my own thread. Most threads I found were for older 2nd gens, and I'm not clear if the older 2nd gens are the same as mine.

The lights came on a week or so ago and have gone away briefly, but always come back on(speedo & cruise always work). I was hopeful that meant it was the rear wheel sensor, it wasn't(replaced yesterday).

The passenger front unit bearing was replaced a year ago when I did ball joints, not ruling that out. I also unplugged the prop valve, no change. I cycled the key 50 times, no change. All 3 brake lights work.

First question, does my truck have 4 wheel ABS? My owner's manual says it does, but I don't know for sure. I've had this truck almost 3yrs and it came to me with only 50k on the clock, now has 116k.

Here are some other symptoms:

slow cranking in the morning-batteries say Chrysler on them. Could be original, don't know how to tell how old they are. Also read a post where a bad battery caused this.



Rear wheels will lock up-verified this by having my wife stand on the brakes. My brakes seem to operate fine otherwise.



Anyone know off-hand if parts stores have code readers now-a-days that will read ABS codes?



Thanks,

Ian

 

[Road Dog]

Most inexpensive code readers won't reach the ABS module. There's two ABS systems for the truck: rear-wheel ABS (one sensor on the rear diff and only the rear wheels are controlled) and 4-wheel ABS (with a sensor on each front wheel plus the rear diff). With the fault light on the ABS is disabled and normal braking will work fine.

First, check the brake reservoir and top it up. It can cause a fault even if it's above MIN.

Second, accelerate slowly and watch the speedo. It's driven off the rear diff sensor. If it stays at zero and then jumps to the correct speed then the sensor needs some love. It could be a bad connection (clean), an unseated sensor (loosen the bolt and make sure it's fully seated in the diff) or a bad sensor (replace).

Third, it could be a front sensor or the ABS module itself. A weak battery could be a problem. If you have the original batteries then it time to thank them for their service and replace.

 

[ichoplin]

Thanks Road Dog. I did add a little brake fluid yesterday just to be sure. I'm headed out to have my batteries checked now.

Ian

 

[ichoplin]

So, does the fact that my rear brakes lock up scream something obvious? I looked over the wires in that area when I changed that sensor. I didn't see anything out of the ordinary. I'll give all that another look just to be sure.

Ian

 

[DavidC]

If your rear speedo works the rear sensor and wiring is good. If you have 4 wheel ABS there will be sensors on each front wheel. If you have these they should ohm at approx. 600 ohms across the 2 pins. Do you have a factory hitch ?, if you do there is a plug on the backside you can unplug and see if that is the issue.

Dave

 

[ichoplin]

Thanks David.

Well, I was on my way to town to have my batteries checked and hopefully get a code read and guess what, the lights went off and stayed off. My batteries ended up being bad. They had Mopar on them, but I have no real way of knowing if they were original or not. I'm thinking they may have been since my truck had so few miles on it when I got it.

Hopefully, it was the rear sensor and it just took a few key cycles for the lights to go out.

I'll post back if the lights come back on.

Thanks again

Ian

 

[TPetroff]

Take to a dealer and have them scan it. Just went through this on wifes 99 Durango. Same symptoms as yours.

Ended up being the ABS controll moduel. $650. Part.

Cost $100. to scan and diagnos. Bought the new controler on line MoPar $300 give or take. Install it go back to dealer had them Flash it.

They have to flash your VIN and tire size. Used controlers won't work because the VIN won't match the ECM and will through a code. (ck eng. light)

Used controlers can't be re-flashed. No aftermarket scan tool will scan Chry. ABS system until after 02 or 03 I think, as Chry. never released the codes to the aftermarket tool group.

TGP

 

[ichoplin]

Surprise, the lights came back on this morning on the way to work. First chance I get, I'm taking it to my local dealer.

If it turns out to be the ABS module, are there special bleeding processes involved? Or do you install and bleed like normal?

I'll post back when I learn what's causing the lights

Thanks

Ian

 

[Road Dog]

The ABS module is electronic and plugs in. I think it's below the radio in the console.

 

[ichoplin]

Oh, I thought it was the thing with all the brake lines to it. So it's gonna be an electronic device? I'm hoping its a front sensor actually, I have receipts for unit bearings

 

[DavidC]

Oh, I thought it was the thing with all the brake lines to it. So it's gonna be an electronic device? I'm hoping its a front sensor actually, I have receipts for unit bearings

It is. I believe what was stated is the air bag control. ABS is under the hood

Dave

 

[TPetroff]

Correct.

And you remove 4 screws and unplug three wire connectors to change the ABS module from the ABS valve body under the hood.

TGP

 

[ichoplin]

Thanks guys. Don't know if this is common elsewhere, but I called my local dealer this morning. They can't get me in to check for codes until next Friday!! That is ridiculous. I asked if all the new dodges we're falling apart or what. I was told they were so busy because they were getting cars ready for winter. I'm in okla, not North Dakota. Very disappointed.

Ian

 

[ichoplin]

A local tire shop I do business with was able to read my codes for me. Turns out my passenger front wheel bearing is bad. This is the same one I replaced in August of 2012. Good thing I keep receipts.

Thanks again everyone

Ian

 

[ichoplin]

The code reader was right. I changed my passenger side hub assembly today and my abs and brake lights are now off.

Thanks again everyone

Ian