The ABS and the P Brake light keep coming on

[ratled]

2002 2wd with a 5.3 and about 157,000 on it. The ABS and the P Brake light comes on about every other trip, light up about 5 -10 minutes into the drive and stay on until the key is turned off. I was just driving down the freeway for about an hour the first time it happened. No changes in the handling, braking and no feedback through the wheel.


2 shops have looked at and found nothing. They were unable to get the lights to come and don’t want to drive it long enough for it to happen. The last shop did a rotate and balance to see if that helps but it didn’t. Everything looks fine and all the fluids are good to go. No slop in the tire as if it was a bearing. Unable to read the codes with the reader I have access to since I have to start with the ignition off and that clears the codes

Any thoughts as to whats next to check on?

Thanks

ratled

 

[treehan77]

My fix to this was to repair the ABS module. Resolder the connections inside. A replacement is kind of expensive, and a junk yard one will likely have the same problem.

 

[Doubeleive]

abs module would likely be the issue as stated above, the code will be gone once the key is turned off because once you cycle the key the module self test's good untill you hit a bump or it shakes enough internally to loose conection again. very common problem, you can swap in a used one or a known good or repaired one as long as the part number is indentical to the original. some places online offer a repair service but you would need to remove the module and send it out and wait for it to be returned. you cannot drive the vehicle with the module out.
if you want to attempt a repair yourself there are youtube video's about how to do it, even with a prof repair service it does not always work 100% of the time.

 

[JamesLond]

Everything doublelive said. I'll add that it's sort of a stressful to pull the EBCM too; it's underneath the car with limited room and you have to blindly ensure the 4 torx screws aren't jammed up with crud or else you'll strip them.

Here's how one of mine looked.


Wouldn't have been able to clean everything up and get the screws loose without my endoscope. Anyways, just do really good diagnosis because you don't want to go through all this mistakenly.

 

[Doubeleive]

Everything doublelive said. I'll add that it's sort of a stressful to pull the EBCM too; it's underneath the car with limited room and you have to blindly ensure the 4 torx screws aren't jammed up with crud or else you'll strip them.

Here's how one of mine looked.
View attachment 370069

Wouldn't have been able to clean everything up and get the screws loose without my endoscope. Anyways, just do really good diagnosis because you don't want to go through all this mistakenly.

yep I had to do one of mine 3 times and stripped one of the bolt heads, had to cut the module out, seems to be the going rate while trying to get one from the junkyard had the same result, some engineers need to be whacked upside the head.

 

[Mudsport96]

So the lighst on are
P ABS well if a T lights up youve got it made.