ABS is coming on at low speeds?

BOOTDOG54

MEMBER
2004 FORD F-150
4.6L
V8
2WD
AUTOMATIC
150,000 MILES

Hello, I'm a mechanic yet having trouble with an ABS problem. ABS pulsates at low speeds, right around 15 mph and lower. Rotors are good, ABS light was on, diagnosed and the problem lead to the ABS box /module. Changed out box/module and the light went out, yet it still pulsates at low speeds. I used diagnostic computer to monitor speed sensors and all numbers are normal and no codes are present. Any ideas? I think its a speed sensor but which one? I hope yall can help.

6 Replies

HMAC300

MECHANIC
48,601 POSTS

This is caused by weak signal to the ABS module. I would check the sensors to see if they are dirty or corroded.

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Tuesday, May 6th, 2014 AT 5:57 AM

BOOTDOG54

MEMBER
10 POSTS

We're using a Bosch program on the laptop in real time it showed the right front seanr was weak so I got new one fixed it thanks for the help

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Tuesday, May 6th, 2014 AT 6:27 AM

JJB1960

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8 POSTS

Well, I didn't see this 1 coming. Haven't done the rotors yet because after driving it on Wednesday and it sure felt like the problem was in the rear. So I pulled the drums of, and after comparing the hardware side to side, realized one of the springs, well both of these retaining springs were the same. So went to the store where I got them and wanted to look at a new hardware pkg. And sure enough they were the same. This is wrong because with them both the same, its hitting the emergency brake and causing it to bind up, which made the cable bind up and push the retainer thru the backing plate and binding everything up. So I think its safe to say that this was the problem all along, I hope. Had to go to work after discovering this and got snowed in in fair play, wait for my ride. Lol. But I had to bend the 1 spring around so it was a mirror to the other 1 and now it doesn't interfere with anything. Things you don't expect. Now I need a new emergency brake cable and then will know. Will keep you posted. Thanks.

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Saturday, March 13th, 2021 AT 5:26 PM

JACOBANDNICKOLAS

MECHANIC
108,179 POSTS

Hi,

We haven't heard from you for a few days. Have you made any progress? We are interested in knowing.

Joe

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Tuesday, March 16th, 2021 AT 6:57 PM

JJB1960

MEMBER
8 POSTS

After the deal with the emergency brake, yes I think I still have warped rotors. We got a couple feet of snow here and have not been working on the truck. I will let you know bout the rotors.