I own a 2016 Audi A3 eTron sportback w/ 60K miles. Last May, I had issues that were traced to the mechatronic unit.... power failures on the expressway, not good!... The unit was replaced and all seemed fine until this past week. This time I was getting critical power failure messages, but it felt very different. I had not charged the battery for several weeks and have been running on gas engine only. I started noticing a delay when I tried to start it, and then it quit on me a couple of times with a critical power failure message. I found a charging station, got it all charged up, then took it to the dealer for a look. They are telling me that the mechatronic unit needs to be replaced again. What the hell?? This is my first, and possibly last Audi. The repair cost me over $4K and I am questioning whether this is truly the issue. Any experience around this would be much appreciated.