"Hybrid System Malfunction" while in a car wash

Hi guys. I took my 2016 Prius 3 through a brushless car wash this afternoon, and about halfway through, the warning light came on and the car displayed "Hybrid System Malfunction // Visit Your Dealer". Has anyone had anything like this happen to them? The car seemed to drive normally from there back to home, so the system is evidently still working - just getting the message on the screen every few seconds.

Given that it happened while I was in the car wash, I'm wondering if it's just that some water got under the hood and tripped a sensor or something. The car was not idling at the time.

I had my 5K service appointment scheduled for tomorrow anyway, but now the dealer wants to have the car there all day. They're giving me a loaner, so that's nice. Still, a little concerning that this is happening so soon after I bought the thing.

 

The car was in Park (it's a standing car wash, not a moving one), and the A/C was on. The battery was only down to 5 bars.

 

Well, among other things, I'm thinking I'll be going to a different dealer for future service appointments. They completely screwed up the schedule and caused me an unnecessary three-hour disruption since they didn't have a loaner car available and didn't even know about my call yesterday. Had issues with this dealer before (it's the one where I bought the car). And that's not all.

They did run the codes on the car, but according to them, it didn't tell them anything definitive, so their "best guess" is that I'd "left the key in the car for a long period of time." The tech advisor then said "Well, if you left the car in Accessory mode for a long period, it would turn itself off...". I had to explain, THREE TIMES, that no, I was sitting in the car with it ON and in Park the whole time, the battery was at 5 bars, and when the car wash was done, I shifted it back into Drive. At no point during this process did I touch the Power button. Still no idea, just "If you see it happen again, call us and we'll set up another appointment."

No, I think that if I see it again, I'm going to call someone ELSE and set up an appointment.


I have a suspicion as to what it might be, though, and at some point I'm going to try a test to see if it's what I think it is. I recall having shifted into Park and leaving my foot on the brake the whole time I was in the wash (which was about 5 minutes tops). I did that because the Pink Elephant system hates it when the car moves while the wash is in progress. Now, Toyota Corporate sent me a notice a couple weeks back saying that there's a known issue with the brake assembly that might cause a warning light to appear (they emphasized that it's not a safety issue). This came in as an "extended warranty" - after the standard warranty runs out, they would extend the warranty on this particular condition until I hit 150,000 miles.

So I wonder if this was that condition. If so, I should be able to repro it by just sitting in Park with my foot on the brake for a few minutes, and that would rule out the car wash as being a factor. I think that's the only time I've sat in one spot with the brake down (as opposed to the parking brake) for more than a minute.

 

I'll try to get to that in the next day or two. Being the on-call at my work takes up too much time.