I get the ESC warning in the warmer months (in Ohio). This started in 2015.

2016 1st diagnostic: GM care paid for it. Dealership charge me $150 to replace the brake pedal sensor. 2nd diagnostic: ESC happened again within one month of service...so dealership did another diagnostic for free. Could not find the issue and wanted to do a more in depth diagnostic can charge me 2x the norm. 3rd diagnostic: Couldn't find anything AGAIN. Got that for free after one of the techs bad mouthed me while I was standing within ear shot - (long story -idiot!)

2017 - ESC warning light again. unfortunately the day I was to take it in the warning light did not come.

Currently I tried a recommendation of grease/lubricate with plain bearing grease all wiring connections. Connections in side dash panel when you open the door, it pulls right off. Also under the hood there are many wiring connections, 2 connected to the computer next to the battery and one connected to the firewall above the battery, apply just enough grease to cover the holes not plug them. MUST (MUST) make sure to disconnect the negative battery while doing this to erase any codes. Crossing my fingers this works.

Update from Jul 31, 2017: the greasing of wires did not work. Stuck on what to do next as when the ESC problem occurs then my brake lights do not come on unless I press down harder on the pedal. Which means I have to slam on the brakes. UGH!!!! hate this car.