Weird ABS problem help

[Zeromarine]

Hey all
On my 2002 sport trac 4x4 over the last year the abs lite would randomly come on. And at times when almost coming to a stop the abs would kick in. So this summer I replaced the rear sensor, still the same thing.
so today I got a right hand front sensor (that’s all they had figured I’d try one 50% chance haha).
Got the new one in and went for a ride. First couple brake applications were good. Then all of a sudden even when going 30mpg barley touching the brakes the abs was engaging all the time. If I mashed on the brakes it would pull to the left like crazy and lock up the left front wheel. (I didn’t touch that side). So I go home put the old one back in and pull the battery to reset anything. Take it for a drive exact same thing. (No abs lite on at all either) Not sure what is going on.
For now I just pulled the abs pump fuse and she works perfect. But would like to eventually get this figured.
Any ideas would be great thanks.

 

[J_C]

I would hook up an OBD2 scan tool dongle linked to a host device (phone, PC or tablet) running Forscan to get the ABS codes and see speed sensor data.

I don't know an '02 Sport Trac, but would have guessed that the front left and right sensors were identical, same part?

If you have a front ABS sensor problem that causes a particular wheel to not brake, during braking it will pull to the opposite side since that is the side braking still. Are you 100% SURE the left wheel was locking up rather than just having the brake working while the right front wasn't?

I suppose I took the long way around towards suggesting that it may be a speed sensor and since you already replaced 2 out of 3 without knowing which it was, that the 3rd one is the next place to look.

However if a wheel bearing is going bad it can foul the speed sensor data. If you are on your original wheel bearings I would be thinking about whether to gamble on speed sensors or replace the hubs which come with new speed sensors too.

Don't let any of this replace my original suggestion which was to get data from a scan tool to see if any values look wrong.

 

[Zeromarine]

Hey thanks !
I’ll see if I can do that not sure as I don’t have a dongle or anything.
Yes both sides are the same part number for my truck.

When I got hard on the brakes the abs activated and pulled to the left. So I’m guessing the side that’s having the abs problem (right front) just wasn’t braking well like you suggested.

I believe it’s the original wheel bearings. It’s got 105,000 miles on it. Maybe wouldn’t hurt to just replace the wheel bearing hub instead ? Do they come with the tone ring or are those attached to the axle ?

It’s just strange how just replacing the sensor caused it to be way worse then before. Even putting the old one back in. The tone ring looked a bit dirt and had some grease on it. Maybe I’ll clean it also.
Thanks for the suggestions.

 

[J_C]

If it's 4WD the ring is internal to the hub. If external, those don't really fail, just need cleaned off if willing to DIY.

The scan tool data will tell you where to focus then you take it from there.

 

[Zeromarine]

Yes it’s a 4wd. I can see the ring from where the sensor goes in. Maybe I knocked some crap into it. I swear also I saw a missing tooth I’ll have to look again.
Thanks !

 

[Zeromarine]

Thinking back when I spun the wheel and was looking at the tone ring I’m pretty sure it was missing a tooth. Either way i ordered a new wheel bearing. So I’ll install that with the new sensor and go from there. Either way won’t hurt replacing a bearing that has over 100,000 miles on it.

 

[German Engineer]

Oh geez, please just stop throwing parts at it and get yourself an OBD2 scanner that can read SBS codes!
They're cheap enough. You should be able to get one that work with Forscan and that can read ABS codes for under 40 bucks already.

Your problem with the ABS system could be anything!
You might even just have a bad connection somewhere that throws a code for ABS pump motor circuit failure code. Or it could be a combination of different problems.
There's really no telling what it is wrong with your ABS system without reading the code(s). And after you fixed it, you will need to clear the code anyways in order to ensure it's fixed and the code doesn't come back on.

Breaks are generally nothing to just fool around with! And even though in most cases the brakes will still work without ABS, it is a serious safety issue.

If you had purchased a code reader to diagnose the ABS system, BEFORE senselessly throwing parts at it, you would have already saved yourself a bunch of bucks. And it will certainly save you more dollars in the future when you have an OBD2 scanner.
I would almost go so far as to say that without using an OPBD2 scanner first, you don't even need to think about picking up a wrench or screwdriver on vehicles like your Explorer.

 

[C420sailor]

Agreed. That said, with that mileage on those hubs, replace the whole hub with a quality unit—don’t just replace the sensor. At 105k they aren’t long for this world, and you don’t want to buy a sensor just to then figure out that the internals are bad. If your hubs were young, different story.

That also said, diagnose first before you blindly buy parts. Sounds like the system is dumping brake pressure to the FR in response to an erroneous signal.

 

[Zeromarine]

Replaced the front right wheel bearing and it’s all good now. I looked inside the sensor hole in the old one looks like it had a couple teeth chipped. And a bunch of debris so who knows. Either way it’s fixed and has a new bearing.
thanks all!

 

[Pete Deering]

Hey all
On my 2002 sport trac 4x4 over the last year the abs lite would randomly come on. And at times when almost coming to a stop the abs would kick in. So this summer I replaced the rear sensor, still the same thing.
so today I got a right hand front sensor (that’s all they had figured I’d try one 50% chance haha).
Got the new one in and went for a ride. First couple brake applications were good. Then all of a sudden even when going 30mpg barley touching the brakes the abs was engaging all the time. If I mashed on the brakes it would pull to the left like crazy and lock up the left front wheel. (I didn’t touch that side). So I go home put the old one back in and pull the battery to reset anything. Take it for a drive exact same thing. (No abs lite on at all either) Not sure what is going on.
For now I just pulled the abs pump fuse and she works perfect. But would like to eventually get this figured.
Any ideas would be great thanks.

I have 1995, and having the same issue. When I but it in neutral the car stops. My huds, rotors capiliers and pads are new. I just replaced the rear and sensor no change. I believe its the absolute module. I pick one up but have Not installed it yet.

 

[J_C]

^ What does "when I (put?) it in neutral the car stops" mean?

I would do as suggested previously, hook up a code scanner, capable of the Ford specific ABS codes and see what they indicate. For example a host device running Forscan app and an OBD2 bluetooth, wifi, or USB dongle if not a more expensive self contained scan tool capable of the Ford ABS codes. The basic tool they would use for free at Autozone, Advance Auto, etc auto parts stores, can't do the Ford specific codes AFAIK.


It might be that your ABS module is bad but that's an expensive thing to try if it is just corroded connectors or frayed wires, or a fuse, etc. Plus many places will not take electronic items back once installed. Some won't even take them back if you didn't install them, though legally I'd assume they are required to exchange for same if you claim it is DOA.

 

[Pete Deering]

^ What does "when I (put?) it in neutral the car stops" mean?

I would do as suggested previously, hook up a code scanner, capable of the Ford specific ABS codes and see what they indicate. For example a host device running Forscan app and an OBD2 bluetooth, wifi, or USB dongle if not a more expensive self contained scan tool capable of the Ford ABS codes. The basic tool they would use for free at Autozone, Advance Auto, etc auto parts stores, can't do the Ford specific codes AFAIK.


It might be that your ABS module is bad but that's an expensive thing to try if it is just corroded connectors or frayed wires, or a fuse, etc. Plus many places will not take electronic items back once installed. Some won't even take them back if you didn't install them, though legally I'd assume they are required to exchange for same if you claim it is DOA.

1.When I driving my explorer going slow down a hill out of driveway. At the of the driveway I needed stop, I used put it in neutral and it stops. If I didn't the brakes would just pulse. 2. I brought a used ABS unit on eBay for $30. I tried everything else. Rockauto sell them.

 

[Pete Deering]

1.When I driving my explorer going slow down a hill out of driveway. At the of the driveway I needed to stop, I used too put it in neutral and it the car would come to a complete stop. If I didn't the brakes would just pulse and the car just keeps rolling. 2. I brought a used ABS unit on eBay for $30. I tried everything else. Rockauto sell them.

My locaL AutoZone can not read any OBD1 cars. What scan tool are you using too read ABS codes on your explorer?