ABS light on, 4x4 high flashing, binding when making turns.

[RCBZach]

2004 Explorer NBX, 245hp 4.0L SOHC V6, 4WD, 139k miles. Only thing not stock is a set of 265/75R16 AT tires. Here goes:

I noticed my ABS light is staying on constantly and the 4x4 high light flashes 8x every two minutes or so. OBD2 reader shows no codes. Battery disconnected for 20 min to try and reset, but lights remain.

I did a search and found others remedied the problem by replacing the rear ABS sensor in the top of the diff. I replaced it, and ($40 later) the lights remain. Searched AGAIN, found another individual who had the same problem...fixed by replacing OSS sensors (same year but the V8). I can't find them on my truck! I removed the transfer case shift motor and everything, but nothing--no OSS sensors that I can see. What am I missing??

I should also point out that yet ANOTHER search showed the problem was solved by replacing a front hub assembly. I feel like the front driver's-side wheel bearings are going, but when I disconnected the transfer case shift motor, the binding ceased to be (although the ABS and 4x4 high lights are still doing their thing).

How many problems am I having?? Are the ABS/4x4 thing and the binding mutually exclusive? Where are my OSS sensors?! This is my first Ford.

 

[rrgone]

I think that at some point in 2004 the Explorers stopped using the OSS's for input to the A4WD system and started using the ABS sensors to detect wheel slip. So my guess is a wheel hub bearing is bad enough to trigger both ABS and 4WD error codes. The PCM is also telling the transfer case to engage 4WD because it thinks a wheel is slipping.

When you disconnected the TC shift motor you also removed power to the electromechanical clutch in the TC. That prevented it from responding to the wheel slip signal from the PCM. Thus the binding stopped. I would leave it disconnected until you get it fixed.

BTW, welcome aboard. Please let us know how you do with this.

 

[RCBZach]

Thanks for the quick reply. I am planning on going ahead and replacing both wheel hubs, as I figure that if one is going bad, the other is not far behind.

I forgot to mention in my previous post that the back of the rear differential is pretty wet. Could low gear dope make the sensor malfunction?

 

[Dave8338]

Thanks for the quick reply. I am planning on going ahead and replacing both wheel hubs, as I figure that if one is going bad, the other is not far behind.

I forgot to mention in my previous post that the back of the rear differential is pretty wet. Could low gear dope make the sensor malfunction?

Indirectly, maybe.

If you have the limited slip rear differential and your rear diff is empty or nearing it, your clutch pack may be grabbing and causing issues...

 

[RCBZach]

Update: I replaced the driver-side hub assembly on the front. Problem solved. Thanks for all the input--it was very helpful!