Hey guys. I recently picked up a 98 Expedition with 105k miles. Very very nice shape but yesterday morning I had the ABS light turn on about 20 seconds after driving the truck. It did the same thing on the way home from work as well. When I got home I figured I'd stick my code scanner on the truck and see what the deal was; the light wouldn't come back on and when I drove it around the block stopping and going. This morning the light came back on, and while it was on I ran the code scanner again with a PASS: No codes.

Sensor or $$$ ABS module? What do you guys think?

 

A standard code scanner will not read ABS codes, you need one that is for that purpose. The most common problem is the rear sensor on top of the rear differential. About $20 and very easy to change, only has one bolt and the wiring plug in.

 

Could it possibly be the ABS Module though? I dread thinking of that being it but if it's highly unlikely it's bad then I'll just pick up a sensor and switch it out.

Thanks!

 

The sheer number of sensors that end up being bad makes it a good bet that it is the sensor. For the money and the effort it is to change the sensor I would say go for it. After changing the sensor be sure and unhook the battery for a few minutes to reset the light.

 

Could be the sensor on top of the differential. I have a 99 Exp and had the ABS light come on. Replaced the differential sensor about 50k ago and haven't had the ABS light since. Only have 161K on it now. Have a vacuum leak to find and fix tomorrow

 

I couldn't wait for tomorrow so I went out and LOOKED at the PCV lines just to see what might be the problem. I replaced a 2.5 inch connection that had collapsed after 161K. Used fuel line. Also replaced the PCV. $3.24 for both pieces, wonder what a dealer would have charged. The sucking noise went away. This is a dual path vacuum line, the other will have to wait until i get back to Texas which I'll do when I'm home and can have a cooler engine than here in Arizona.

 

$185.00, about. So tell your wife, and go out and **** away the change on something cool for yourself, you deserve it>>>>>>>>>.

 

I had a merc grand marquis do the abs light and the sensors behind the rotors ended up being saturated with rusty particles. Looked like they were magnetic i guess. try cleaning them if they are similar.

 

I second that , mine only needed cleaned they had grease on them and when i thrash about in the mud (97 Expy lifted) my abs light dont stop fickering till i hit the water hole on the way out of the trail ...my 2 cents......chuck

 

My ABS light was constantly on. I removed the rear differential sensor and simply cleaned it. It had a fair amount of metal dust on it which definitely was causing the problem. Reinstalled, started the Expy and the light is now out. Pretty easy. I wonder if the sensors are really failing or if they are simply getting caked with grease/metal and people are not giving them a chance after a cleaning?

 

does anyone have a pic of where the sensor is? sounds simple enough to swap out, but I want to make sure I get the right thing.
thanks for your help. This site has always come through for me...

 

I don't have a picture, but you can't miss it. It's right on the front-center of the top of the rear differential. You remove one bolt and then gently pry it up and out of the differential case. You want to be careful not to let any dirt or debris fall into the case. I took mine out, cleaned it and also the hole where the sensor fit in. That was enough for mine to start working again.

Here's a picture of the part at Autozone:

AutoZone.com | Vehicle Selection - Year

 

thx for the speedy response... I'll take a look tomorrow.

 

FYI - my rear ABS sensor just failed. It was working for a short while after only a cleaning but it has now completely failed resulting in a constantly-on ABS light on the dash. I picked up a replacement part at AutoZone ($18.99) and installed it. Light is off now, probably for good.

Sooo.... just cleaning the sensor is a very temporary solution. Only worked for two days for me. For the price of the replacement part, it's not worth jacking the Expy up twice (even though it really only took about 10 mins start to finish the second time around). Just a follow-up for my previous posts.