I know I have asked this before but I am going to ask again to see if anyone else has an opinion. I have a 2001 Durango. The rear end was replaced and then "suddenly" there is an ABS engagement issue that can not be figured out. Basically the Kelsey Hayes system will engage when the pedal is pushed but "only" at 3/4ths to full bottom of the pedal. Here is what I have tried. I have replaced the entire module and pump (bench bled), then all 4 wheel cylinders bled starting at the back and working to the front, turned both the rotors and drums, new pads and shoes, rear speed sensor ohmed at 1,880 ohms both front speed sensors ohmed at 1,680 ohms. All bleeding was done by holding the brake down while bleeders were opened (not the pump it up method), and damn near 3 quarts of new fluid through the entire system. I do notice a "clicking" noise coming from the front left hub kind of like the speed sensor magnet contacts are clicking on the shaft. It only does this on occasion but when it does it it often stays engaged for up to 30 seconds after the brake is lt up. I took it to the dealership and they said they can not find the problem and then said they would have done the same procedures I have done.

 

You didn't bleed the ABS as you stated you bench bleeded so you must have taken off the master cylinder to do this. You must use a DRB III for this:

SERVICE PROCEDURES

BLEEDING ABS BRAKE SYSTEM
ABS system bleeding requires conventional bleeding
methods plus use of the DRB scan tool. The procedure
involves performing a base brake bleeding,
followed by use of the scan tool to cycle and bleed the
HCU pump and solenoids. A second base brake bleeding
procedure is then required to remove any air
remaining in the system.
(1) Perform base brake bleeding. Refer to base
brake section for procedure.
(2) Connect scan tool to the Data Link Connector.
(3) Select ANTILOCK BRAKES, followed by MISCELLANEOUS,
then BLEED BRAKES. Follow the
instructions displayed. When scan tool displays TEST
COMPLETE, disconnect scan tool and proceed.
(4) Perform base brake bleeding a second time.
Refer to base brake section for procedure.
(5) Top off master cylinder fluid level and

 

I understand that... but both dealerships did this both again manually and through the scan tool and the vehicle still does the same thing. They also used the scan tool to determine ALL wheel speed sensors were functioning at vehicle rest. What I am trying to figure out is the possibility that the front left sensor is just bad a certain speeds considering the ABS ebgages at lows speeds between 5-15 mph. It engages when slowing down and sometimes take off. The only thing I have noticed that I thought was odd was that after pulling the sensor out of the front left wheel I noticed a a "TON" of grease in between the toner rings. They also said it was normal and that that could not possibly make it engage. Basically I have been told to either just ignore the fact that it comes on or pull the fuse. That is a pretty bad conclusion coming from 2 dealerships. I do not get it. It has a new ABS pump and module, new brake pads and shoes, drums and rotors turned and all 3 sensors front and back show 3 mph while the vehicle is sitting still. They also said that the sensors reading 3 mph on the scanner while the vehice is at rest is normal. Who the hell can you trust anymore? Even after you pay the money and still have the problem... no one nows how to fix it. I guess I have a good lawsuit when I go to slow down and end up rear ending someone and I pull the paperwork out that the dealer states "their is no issue!" Hey... for all you reading this... please do NOT lock up the brakes in front of me... "I may NOT be able to stop!"

 

I would replace the rear speed (ABS) sensor. If it states that you are at 3 mph when at a stand still then that sensor is reading incorrectly. There is also the transmission output sensor that could be a problem and usually they are replaced in pairs, however it sounds like the rear sensor is shot.

Really it makes a lot of sense (at least to me) if the sensor is resonating because the magnet sleeve is worn then it would think that the truck is slightly moving when it is not. The 3 mph different is engaging the ABS as it see's a slip on the front from the rear.

 

Well... I can't say I didn't try! I bought a new rear wheel ABS sensor from NAPA tonight ($35.00). I took the old one out and put in the new one. Guess what... I backed out of my driveway, put it into drive, got up to about 12 mph in my neighborhood, hit the brakes (started praying), and just as I thought... the ABS motor under the hood started to engage again. I drove a little further, hit the brakes (I was doing about 25 mph), turned left while pressing the brakes, and the ABS engaged again for about 5 seconds then I let off the brake. I went to pull back in my driveway and guess what... the ABS started to engage again. This sucks... what else can you do? I'm about one thought from pulling the fuse, the dash, and pulling the ABS and brake light lamps out of the cluster.

1. New brakes & shoes
2. Rotors/drums turned
3. Front sensors "old" but tested fine
4. New rear sensor
5. Almost 2 gallons of brake fluid & flushing
6. Dealer "bleeding"
7. Manual "bleeding"
8. New ABS & motor installed
9. Stopped counting pages of service manual literature
10. Stopped counting beer cans & answering wifes complaints as to when it would be fixed
11. Overpaid dealership service costs for something they can't fix
12. "Starting to sound like a MasterCard commercial"

My solution... "just pull the F@CKING fuse & call it a day!"

 

So I deciced to take a different approach tonight. I actually used my voltmeter to test AC current on each sensor. All the wheels were spun in the forward direction as hard as I could. The front wheels were easy... the left front tested at .30 at its highest point, the right front tested at .50 at its highest point, the rear was a little harder to spin (aka rear wheel drive), but I am not worried about it since I just replaced it and the fact that I got a reading about .45. I am leaning at tryingto replace the left wheel speed sensor since it was the one that was audibly "clicking" when the ABS engagement would take place from time to time and the fact that I had to spin the "hell" out of it just to get .50.

 

Sounds good, just hate to see more parts go at it.

Check harness connections for corrosion as well.