My 2014 Prius V with 75K miles recently has an issue described above. I first noticed it a week ago when I was driving into town on the highway. I went to accelerate and the acceleration felt slow, hesitant, and heavy. There was also a distinct smell coming through the vents--it could have been exhaust-ish. hard to describe. The maintenance light is on because I need an oil change, but there is no other warning light on. I took it into the local garage and they tested it with the computer and nothing showed up. He just said I needed the oil change. It's been very hot here. And there have been mice, though the mechanic said he didn't see any damage from the mice. I drove it the next day and there was no problem. Then yesterday it happened again. The issue started when I was coming down from the mountain during an acceleration, and then continued the remaining 20 miles home. It felt like the gear shifting was slow, though I read on this forum that the Prius doesn't change gears...but that's what it sounds/feels like. I called a reputable Toyota garage in town, explained what was going on and they recommended taking it into the dealer. The dealer has a middling reputation, so I thought I'd see if you good people have any insight into what may be going on before I contact anyone else.
Possible limp mode of the inverter. Local garage may not have techstream required to read hybrid codes. Basic failure is common and Toyota covers it beyond warranty. The check engine may not light, usually the car symbol with the ! located far right. Inverter temp limit is less than coolant limit and can be a problem at 105f [Ambient] in low speed or heavy regen especially if the undercover is missing. Also verify radiator fans both run with ac on. Finally inverter or engine water pump. Both should show reservoir fluid flow when hot. Local shops are not great at diagnosing hybrid issues.
It can be a problem at the 105f AMBIENT he and I have had for the last three weeks. Rule of thumb is inverter electronics will run about 45f higher max which does push a limit.
The car can also limit current in/out of the battery at higher battery temperatures, with a direct impact on the amount of battery-assisted acceleration you can get. The inverter has to be part of the power flow even when only the engine is in use (that's just how the transmission works), so an inverter-shutdown limp mode is very limpy. But a reduction in assist power from the battery will mean slower acceleration and higher engine revs (sounding like a conventional tranny being late to upshift).
Thank you all so much for your input! It helps me to at least conceptualize what may be going on. I ended up making an appointment with the dealership and will bring it in this coming week. Fingers crossed it's an easy fix.
Another question... do you think it is safe to drive to the dealership? It's about 13 miles and I can avoid highway driving to get there...or should I have it towed?
You may have an intermittent failure in one or more of you ignition coils - heat related. It won't throw codes, since it repairs itself when they cool down a bit. If it only happens when it's hot and your working the engine hard - that's a possibility, though 75K miles is a bit low for that failure. Good Luck...
If it's a constant, reproducible issue it should be easy to fix. If it's a heat sensitive component; that drops out once in a while, and doesn't do it at the dealership. They will probably bill you for the diagnostic and send you on your way.... You'll have to wait for the problem to get worse/consistent enough to throw a code or track it down yourself. Good Luck...
I brought it into the Toyota dealership. They couldn't find anything wrong with it. The technician said with the heat and coming down the mountain, the battery would charge with all of the breaking so the system could have had trouble balancing the battery charging with the powering the engine. (terrible paraphrasing). Since it was an intermittent issue and not showing up when I brought it in, they couldn't diagnose it. Thanks everyone for your input!
$165.00 to check it out. In the end, I think it could have been bad gas. It also hasn't been as hot out as it was...
