The brake warning light comes on but only for 1x mile. It comes on consistently under two conditions:
1. In the first drive of the day, the brake warning light comes on after 4-5x minutes while traveling. Since we travel on the same route each day, the light comes on roughly the same place and goes off after 1x minute. The route is uphill, less than 3% grade, and straight for 3.5x miles.
2. After 2-3x hours x travel at freeway speed, the light comes on for 1x minute.

I took off the wheels and found no leaks and the pads are within tolerance. I check the master cylinder and the lines to the wheels. I saw no leaks. Then, I took the vehicle to a repair shop. They replaced the brake booster and a sensor. No change, same result.

After these checks and driving the vehicle, I have good confidence the braking system is fine, and I am getting a false positive warning.

Any suggestions to fix this problem, other than ignoring the light?

 

It is important to know under what conditions the lamp would illuminate.

If the level sensor in the master cyl is not working correctly is one of those conditions.
Since no leaks were found , that is helpful, and sometimes an imbalance in the brake hydraulic system pressures can cause the lamp to come on also . When was the last time brake work was done to the vehicle? Was the hydraulic system opened then ?

It might be a good idea to check the parking brake light switch , which, if misadjusted or malfunctioning could cause the lamp to come on also.

 

I am having the same issue with my 2015 Explorer. Intermittent "Check Brake System", typically when driving on uneven terrain. It has happened when driving over a bump or when turning on gravel, once when taking an off ramp a little fast. My first inclination was to add brake fluid, which was a little low, but that doesn't seem to have fixed the problem. I don't see evidence of any leaks. I am guessing it is a sensor or switch of some sort that gets jostled around. Any other ideas here? Thanks.

Chris

 

Newer vehicles do what is called a pre check. That check is done when the key is turned on and if the readings the computer gets are different from what they should be, the system will notify the operator of a problem within the system, which could be a poor or open connection or a problem with a sensor.
A capable scan tool is required to diagnose these problems , unless you have unlimited funds and can afford to replace a bunch of parts hoping you hit the questionable part or circuit.
It will be cheaper in the long run to have the vehicle checked by a good shop and then decide what you want to do.
Some of these jobs can get a little involved and a better move would be to have the shop handle the job.