My ABS light keeps coming on randomly. Sometimes it's on for a full day sometimes a few seconds. It's pretty weird because it doesn't throw a code or anything. Kinda stuck on where to go from here.

 

The cheapest easiest check is to address the rear sensor on the differential, first by pulling it and wiping it if it has iron particles attached, and replacing it if that does work.

For one reason, the ABS light will go on if there is a discrepancy between the speed readings off the three sensors. So it can a front hub going bad or the rear sensor, but the rear sensor has a higher failure rate. The rear harness also has a high rate breaking a wire from fatigue if you have a higher then normal road oscillations, or if you have a lift.

But until you can track the wheels output, and Forscan can do that, you just shooting in the dark.

 

Well my truck only has a 2.5 in level up front and I just changed that rear sensor in the differential about 3 months ago. So should I just pull it out and clean it and see if it stops giving me the light?

 

I just went through this. First check for ABS Codes. If the ABS light comes on and off it has a stored code. That code may tell you exactly what sensor reading is faulty to the PCM. Use a scanner that can monitor front right, front left, and rear sensor inputs. I use Forscan on my phone for convenience. In my case my intermittent issue was a front right sensor. Somehow moisture got in there so I ended up having to cleaning the few rust spots off of some of the teeth that the sensor detects and I reshimmed the sensor closer. All has been well since.
Start with getting the codes.

 

I ignored code because he said he didn't have any. Without codes and the rear sensor recently done, you have to look for discrepancy with the tools.

 

It's not that he doesn't have any, he probably just didn't check in the right place yet.

The code is obtainable through the ABS module and you have to use a scanner that can access it. Using FORSCAN you can access all the modules individually to check for codes. If the light comes on there's a code. I hope I'm clear enough for the OP.

 

One other thing worth checking id the plugs on all three sensors.
Mie would during the winter light the light every now and then.
I used the scan tool I have (Ford VCM with IDS) to see what the issue was.
It would always be the right front sensor reading low, The plug was week
and would do that when it was cold out. Once it warmed up things were fine.

 

Sooo the scan gauge 2 probably wouldn't pull that code then? When the light is on i'll check for codes and it doesn't give any. I think i'm going to start by pulling the sensors and cleaning them and go from there.

 

SG2 has limitations. Pete talked about Forscan for a cell phone. Good tool for a few dollars, but you need an interface for the OBD2 port, also just a few dollars.

 

I'm going through this right now with Big Blu, found out yesterday it's the drivers side and harness. I thought I saved one from my old hub assembly. I still looking for it.

 

The Wife did it

but ON'T let see I said that. I think I still have some life to live.

 

Haven't been on here for awhile but it was the sensor in the hub assembly. It was rusted in there haha long story short I had to buy a whole new hub assembly and it's finally gone.

 

That's what I expected (Not the total hub replacement part, lol). Thanks for checking back and letting us know.

 

Hey no problem. Thanks for all the advice. I appreciate it!