Klem531 wrote:
Billwill wrote:
I presume you checked the sensors on the wheels?
May be a dirty sensor, frayed wire etc. and codes should be posted stating which wheel it is!

This is the 4th or 5th time I've made repairs to the ABS system on my liberty. Both rear sensors had broken wires in the past and have been repaired. This time around the code I had said "communication loss with abs controller". I assumed it was the chafed wire I keep reading about but I couldn't find anything. So I bit the bullet and replaced the ABS control module. Just need to get it programmed now and see if that fixes the problem.
Wheel-speed sensors often become contaminated with fine metal particles. The problem causes erratic wheel-speed signals that confuse the ABS computer, causing it to disable the system, store a trouble code and turn on the anti-lock warning light.
Metal chips caused by normal drive-train wear, accumulate on the sensor tip over a long period of time.
Remove the wheel-speed sensor clean it, re-install it and retest the system, doing this should clear the problem.
Also, change the differential oil, open up the differential and carefully wipe out the bottom of the housing. There is a ton of metal shavings at the bottom along with muddy/muck. You'll need to stick your hand in and drag out all the metal shavings and the muck resting there, use plastic gloves.
I don't dispose of the old ABS sensors if they test out to be good, I clean them with brake fluid and keep them in the box that the new ones came in. I store them on the shelf and easily swap them out every time the ABS light comes on again. It makes for a quick easy repair that usually occurs every 12,000 miles or so.
Replacing the ABS harness at the sensor, is also another problem that happens at that spot. The problem is that the thin connector wires fray from the inside due to all the shaking that is going on while the vehicle is in motion and it will be difficult to pin point the location where the split occurred in the wire because the plastic shielding around the wire prevents it.
If a broken wire in the harness is not the problem yet.... then rest assured that it will be in the near future.
It's best to replace the ABS harness now while you're working in that area, rather than later when it's broke.