Speed Sensor Location

[pepsiking]

I have a 2000 Explorer AWD. I am having the same problems as many others with the ABS activating when coming to a stop. No ABS lights, no pulling to one side, just the ABS activates the last few feet before stopping. I figured I would try changing the rear speed sensor just due to the price and ease but I don't know where it is. I have searched and some say it is in the rear diff and others say it is in the transfer case. Can someone point me in the right direction please. I don't know exactly what I am looking for so if I at least know where to start looking that will help.

Thanks in advance.....PepsiKing

 

[Turdle]

Your speed sensor is indeed in the diffy housing

 

[Trebor]

i dont belive your problem is related to the speed sensor, but rather with your abs itself. if its activating your abs light should come on momentarily untill its no longer used. and since u said you lights doesnt come on it could possibly be a bad abs sensor and i would look into that first. also it shouldnt be coming on unless there is significant difference in the speed at which your tires are going when coming to a stop. you may just have a fault abs system but it would need to be further diagnosed to be sure

 

[pepsiking]

i dont belive your problem is related to the speed sensor, but rather with your abs itself. if its activating your abs light should come on momentarily untill its no longer used. and since u said you lights doesnt come on it could possibly be a bad abs sensor and i would look into that first. also it shouldnt be coming on unless there is significant difference in the speed at which your tires are going when coming to a stop. you may just have a fault abs system but it would need to be further diagnosed to be sure

Can you explain to me how the abs system works then? I would think that if I had a bad sensor (left or right) that I would experience a pull to the opposite side or is that not how it would work? Is there a way to clean them or is it just a remove and replace procedure? I don't want to spend a ton of $$ on this if I don't have to. I have never done anything in regards to the ABS system so I don't fully understand how everything works exactly. Any help you folks can give me is greatly appreciated!

Thanks again!

 

[gijoecam]

if its activating your abs light should come on momentarily untill its no longer used.

Not on a 2000. That light should only come on at start-up when it runs the diagnostic, or if the system has detected a fault and stored a code. It should absolutely NOT come on during an ABS event.

Can you explain to me how the abs system works then? I would think that if I had a bad sensor (left or right) that I would experience a pull to the opposite side or is that not how it would work?

That's exactly how it would work if it was a front sensor going bad.

Is there a way to clean them or is it just a remove and replace procedure? I don't want to spend a ton of $$ on this if I don't have to. I have never done anything in regards to the ABS system so I don't fully understand how everything works exactly. Any help you folks can give me is greatly appreciated!

Thanks again!

You're on the right track, but without a proper and thorough diagnostic, it's a guessing game at best. If you could get a shop with an NGS scannerto hook it up and watch the ABS sensor PIDs, they would be able to see exactly what sensor or other item is triggering the ABS event.

Now, that being said, the sensor on the diff certainly can be the cause of it. However, it's a guessing game at best. The sensor itself is mounted on the top of the diff housing... It's the only thing there with a wire connected to it.

Good luck!

-Joe

 

[E-rock]

i replaced the speed sensor in teh rear diff when my abs light came on and after i replaced it and reset the battery/computer, it hasnt come on since then, but my speedometer still doesnt match the correct speed. from what i understand the 4 abs sensors attached to each of the hub housings get the correct speed, but sometimes they can offset an abs light if they are dirty or malfunctioning. i would jack up the truck and take a look at them. good luck

 

[pepsiking]

OK, I finally got back around to fixing this. I replaced the rear abs sensor in the different and my problem is still there. I had the front brakes off this week and tried to get the front sensors out of the hubs but they wouldn't come out. Is there a trick to getting them out?

Another tidbit of info I have figured out is the abs only comes on when I am making a left hand turn. It will NOT do it when I am turning right. At this point I am thinking bearings are worn in the hubs causing movement to one side or the other. They do not feel sloppy but I don't know how much they would have to move in order to cause a problem. Maybe I am barking up the wrong tree here, I don't know. The truck only has 53,000 miles on it, I would hope the bearings would last longer than that!

As usual if anyone has any further ideas they are greatly appreciated! I am trying to avoid paying the $65 for a shop to tell me which sensor is bad...unless someone knows a way to check them myself.

Thanks!

 

[pepsiking]

So I finally took her in to get the ABS codes pulled and they came up with two of them. One for the front left ABS sensor failure and one for the ABS hydraulic Pump Motor Circuit Failure. What are the odds that the sensor is causing the pump motor code to be thrown? I am hoping that I can just replace the front sensor and it will fix everything but what do you think?

Give me your suggestions please!

Thanks!

 

[gijoecam]

Did they attempt to clear the codes? They should have cleared the codes and seen what came back up.... If both of them came back up again, then they should have diagnosed the speed sensor using the service manual flow chart, then tested the ABS motor through the diagnostics. Just pulling the code doesn't confirm the problem.

Now, as for the left sensor, IMHO, look closely at the wiring... It could easily be a chafed or broken wire, not necessarily the sensor itself. Could also be a fuzzy contact on the pins where it connects too. It plugs into the connector in the front of the wheel well IIRC.

As for the motor, if, in fact, it's bad, replace the ABS module... that's not cheap. Might be able to find a salvage unit in a yard somewhere, but even used ones aren't cheap...