ABS Sensor Light

I'm almost ready to buy a 2004 prerunner sr5 6cyl.
Only thing I'm really aware of is the ABS light goes on and off.
Owner's mechanic and 2nd opinion tire shop say brakes are fine, can't explain light on/off behavior.

 

Could be a sensor failure in one of your wheels...

 

is this a trial and error discovery process or is there an electronic means of diagnosis?

is this a red flag do not buy issue or a minor issue?

 

The light indicates any kind of issue with the ABS. It could be a sensor, wiring problem, module problem, abs motor, or brake switch to name a few. You need to have the system scanned for codes to find out exactly what the issue is.

 

Check the simple things first. It could just buy low on brake fluid for various reasons.

 

Here's a way to check it yourself. I've posted this in a couple of threads.

 

This is a good thing to check. But that would only turn on the red brake light. Not the ABS light.

 

Oh my mistake. Should've thought more before I posted haha

 

By on and off, do you mean it just kinda comes and goes? Or does it blink?

Having something plugged into the OBD-II port (like a scangauge) will put the ABS computer into some kind of test mode and cause the light to flash. Mine flashes and everything is in working order.

 

Yup. UltraGuages do that as well. Mine does it randomly.

 

I don't have a scangauge, just a bluetooth dongle to link up with my phone. But yeah anything that is plugged into the port will cause it.

 

Mine does it pretty much everytime I hit about 60mph...Never seems to come on at low speeds, but as soon as I hit the highway on it goes. Turn the truck off and on and it's off again. Mine seems like it just needs some electrical cleaner, but I'm not really sweating it..

 

More like sometimes it's on, sometimes it's not. Not blinking.

 

Sounds like an intermittent fault, every time you cycle the key the system checks itself. If no faults present the light stays off, if something wrongit turns light on. The fact this is happening while driving leads me to believe there could be a short in the many looms of wiring or maybe even a bad abs computer. Definitely should have it looked at and diagnosed before purchasing the truck.