On Monday, July 1, the rangers came out and performed my second annual maintenance. All seemed well. On Tuesday I washed the car, then drove out to the centennial trail and parked for an hour and a half in the sun while walking. We're having out first heat wave of the summer and it was brutally hot. The late-afternoon high was 99 F. After returning home and showering, I drove from Spokane Valley to Hayden Lake, ID, probably 35 or 40 minutes, and parked in the sun again while visiting with a friend for something between 30 minutes and an hour, and then started home. Something like 10 or 15 minutes into my drive home, the car chimed at me, and the little MFD said (IIRC) "Powertrain problem. Service required." I tapped the display to make the message go away, and a minute or two later, it repeated. It did this every little while until I reached a town where I could safely get off the road and park at a mini-mall. I phoned Danny, the service manager at the Seattle store, and he ran a remote diagnostic. About a half an hour later he called back, saying that it looked like a fan problem. He offered to give me the number for roadside assistance (which I already have in my phone) but I didn't want to wait the several hours it usually takes for a tow truck, and I also didn't want folks to see a Tesla on a flatbed. It would give the wrong impression. But mainly I didn't want to wait. Danny told me that if the car overheats, it will shut down with only about a sixty second warning. But he also told me that the temperature indicator would go to yellow before red, giving me a few minutes warning, and in answer to my question, said that I could drive it gently if I wanted to take that chance. It is HARD to drive the Roadster gently, but I did it and got home fine, the temperature not having gone any higher than it had been most of the day, which was the PEM still in the next-to-last blue bar. The rangers were still in Idaho, having just finished another service call, so they returned in the afternoon and examined the car. Finding nothing else wrong, they had a new PEM and fan unit overnighted to my house, and at 8:00 a.m. yesterday (July 3) they installed the PEM and fan, under warranty, charging me nothing. (I of course had paid for the annual maintenance.) They finished up at about mid-day. I call this A+ service. They were really great. I presume the problem was probably waiting to happen and manifested due to the heat and the long drive, and was not related to the maintenance done the day before. FWIW, today it was not as hot, and I didn't make a long drive, but I did park in the sun at the walking trail for two hours, and when I got home the PEM was still in the blue, but it was the last blue bar. I would pay for an upgrade to a water-cooled PEM if there were such an option. My battery pack and motor never get hot, so I have no need for a water-cooled motor, and of course the battery pack already is. We don't get a lot of hot weather in Spokane, and I'm out of town (hiking in Canada) during the hottest part of the year, so it's not a big deal for me. And I wonder if maybe parking in the sun is harder on the PEM temperature than driving in the heat. Maybe it gets more air circulation when driving. Just thought I'd share this.