Had this problem previously, was just low brake fluid. I accelerated hard on dirt and lights came back on. Brake Fluid level is at upper line. It went off for a a while then came back on next time I started it. I checked all the brakes and they were pretty low so I replaced all 4 rotors and pads and flushed the brake fluid. Still have the problem. I bought a brake fluid level sensor but not sure how to remove the old one, anybody have any ideas on how to remove it from the master cylinder or anything else I should check? I really need the ABS on snow covered roads. I also replaced the front ABS wheel sensors.

 

Here is a thread that should answer your question.

https://www.myg37.com/forums/showthr...errerid=369648

 

Hey Gary heads up this is a brake fluid level Switch not sensor which means just like the name intends SWITCH continuity on or off.

This specific switch grounds when it's empty.

To take off the Reservoir you need to push a sliding pin out so you can pull the reservoir out which can be a pain.

The switch itself since it grounds, you could disconnect the connector and jump the terminals and replicate the problem. If the problem doesn't come back you can assume that it's this switch.
If you jump it and still persists then you can forget about this switch since replacing it will only do the same.