NHTSA Complaint #11684827 — 2017 GMC YUKON

At low idle speeds like in a parking lot we almost hit another car because the brakes were very hard to press. No power brakes. Felt as I was having to stand on the brake pedal with both feet to stop my vehicle from hitting another car at a grocery store parking lot going 5 mph! A light flashes on and says”service brake assist “ light goes away and drives normal and brakes normal except when you get to a stop sign, or traffic light. This happens a few times and I’m not driving the car because of it because I might hit someone