2013 Chevrolet Captiva Sport

Reporting for my Mother in law. Confirmed by me several times. First incident occurred while she was driving, dry roads, normal traffic at approximately 65 MPH the front brakes locked up and abruptly bought the car to a stop. She was half in the traffic live lane and half on shoulder. She called me and I went immediately. I got there in about 30 minutes and there was several people trying to push the car off the road and all said it wouldn’t budge. I felt the heat of the left front brake was extremely hot. I sat in the car, started it up, attempted to get it to move, it wouldn’t. I figured it was electronic as there was no DTC/MIL lights. I thought the quickest thing I could do was remove power which I did for about 3 minutes. Started up and it drove to shoulder. We switched vehicles, I drove hers, I was traveling 65 mph when the stabilitrek service message showed on display and two minutes later the car stopped on its own again, I was barely able to get off the highway and people were honking swerving around, one yells to fix my brake lights! Still no MIL Check Engine light. This is IMO a safety issue as there is no warning! I was able to drive short bits to get it home. Only after I got home, car cooled, went to try and drive with scan tool hooked up it threw a code for ABS/TCS system pressure circuit malfunction, DTC C0131-5A! It has cleared a couple of times and each time you drive it and the brakes lock up, front left-rear right and vice versa, no brake lights, just uncommanded brake pressure! Oh and the stabilitrek service comes on after as well. It’s been to two shops and not fixed yet, one place quoted $2500 because he said it could be anything and his state of the art equipment can’t pin point the actual issue but he did confirm the locked up brakes with indicated partial pressure applied for no reason. This could definitely cause an accident!