As I have had no luck trying to diagnose this on my own (yes, I did search but didn't find much about what to do). I was driving to visit my family around New Years and while driving my ABS light came on. At first I went S###. At my next stop for gas I used my tuner to check for any codes it was throwing, but there wasn't one. Shouldn't there be one with the light coming on? And if any one could help as to what I can do to try and figure out what is wrong and fix it, I would greatly appreciate it. Thanks to anyone who can help. 2003 f150 5.4

 

Mine has been on as long as I've had the truck,so nearly a year. No telling how long it was on before,never caused any issues.

 

My did that and it was the rear wheel speed sensor and once I changed that it went off

 

Yeah I have heard that there wont be any issues even with the light on, I just dont like having lights like that on my dash. call it OCD if you will but there is obviously something that made it come on and I would like to figure that out.

 

and how did you figure out that it was the rear wheel speed sensor? you go into a shop or do it yourself?

 

Does your cruise control work? I think i had issues with my light till I fixed the cruise control switch on the master cylinder. Could be wrong tho.

 

Yes, cruise control has been and was ON at the time the light came on. Thank you for the idea tho. Did not know they were connected.

 

Check the codes. The rear sensor code should pop up if it is bad. I've seen the front wheels set a code, yet after replacing the wheel bearing assembly, didn't cure the problem. It turned out to be a grounding issue at the main connector to ground. Sometimes, just unplugging and replugging in the sensor can make the code go out. There is a lot of dirt and crap that can make the sensor not read correctly. Including being bad. lol. Good luck.

 

The speed sensor is on the rear wheels, and ur ABS sensor is on the front wheels. Mine just tripped a few days ago, and low and behold the wife bought me a diagnostics checker. I checked it, and it showed a faulty driver side front ABS sensor. Take ur wheels off, and check to make sure those sensors are intact. On the front wheels, they are connected by 1 bolt through the knuckle.

 

I had a shop look at it then I changed it myself