I am new to this list and need a little help. Own 2001 F150 4X4 and yesterday the ABS dash light came on after a drive on a rough street. Then drove it later and the light stayed off. This morning the light came on again after backing out of the driveway and stayed on until I turned the vehicle off at my stop. Then when starting up again, the light stayed off . What could cause the intermittent action of the ABS light/system. I should note that 2 new sensors were installed by the dealer last fall when I bought this used truck. Other that this, I have not had any problems even though there is 186,000 kms on the speedo.. Thanks in advance for any advice.

 

Were the roads wet and sloppy when the light came on? My ABS light will come on in the wet but then once everything dries up it wont come on.
You said that the dealer changed 2 sensors last fall, which sensors were they? There is a sensor for each front wheel as well as a sensor for the rear differential. Its possible that whichever sensor didnt get changed has now failed.

 

I'm actually going to see if I can get a code, mine went on last night and yes, I did just drive through puddles in a gravel yard at work. You know the kinda crap that is driven over so much it's like really soupey cement (definetely smells like it) so that and the fact I need new rear pads/rotors. We'll see.

 

Ive tried a few times to get codes with my OBD-II scanner and Ive never gotten any. From what I understand you need an ABS code reader.
Ive considering just replacing the sensors because they only cost about $20 each. The 2 up front look to be pretty easy to replace, but the one on the rear differential looks like it could turn into a real project!

 

Could be a dirty abs senor on the front wheel hub, could be a bad sensor, or could be a bad wheel bearing causing it.I had bad wheel bearing on my f150 that would activate the abs when I turned slowly in a parking lot, like into a parking space.

 

Now the light comes on and stays on. I drive about half a block and on it comes on. I believe the two front ones were changed and didn't know anything about the back one. Something I will look into. I guess that intermittent action was the sign of one of them beginning to fail...Thanks

 

Reading the factory shop manual, the huge bible-like ones, it's hard to tell, but I'm going to try inspecting a bunch of stuff this weekend. If they need replacing, they look easy enough to do and cheap enough. I'll bet the got something gummed in there when I went baja'n through the yard the other day with that soupey gravel mud water.

 

That or you have a frayed wire or a spot where the wire is exposed and it shorts out when it gets wet.

 

Either way, lesson learned!!! Sorry, I kinda hijacked this thread, hopefully what I find helps though!

 

I tested the front 2 for resistance, within ohm spec so they are probably ok, the rear had no reading so I'll bet it's shot. The manual is pointing me towards the rear always talking about RABS, rear ABS, so it seems logical now. I think I'll replace and see.

 

Replaced the rear sensor, problem solved.