CVT transmission warning light

There are a small number of lights on the dash (the Master Warning Light is one of them), that can light up to tell you about any of the problems the car's computers are able to detect (there are hundreds of those). In theory, which dash lights are lit can tell you something very general about the area of the problem, but in practice, very commonly, several lights will come on together, because the car's computers share information, and in several cases there is a trouble code defined in one computer that just means "heard this other computer was reporting a problem," so its warning light will also come on.

So in practice what you do—it makes no sense to skip this step—is when any of those dash lights come on, you plug in a Prius-capable trouble code reader and let the car tell you what problem(s) it is reporting. If there is a problem with the CVT it will say so. When you turn to the repair manual to look up the codes you read, if some of them are described as simply showing the computer reporting them heard about a problem from another computer, then you back-burner those codes and look closely at the ones reported by the other computer they refer to.

It's a different way of working, compared to wrenching on older cars by guess and by golly, but it's pretty straightforward once you get the hang of it, and it usually gives you a wealth of information to go on when there is a problem.

Regarding the transmission fluid, there isn't any sensor for the level, but it would be really rare for it to get low without some kind of physical damage. It isn't used to transmit power in any way as in a conventional automatic transmission; it's just there to be slippery and cool things, and it is sealed in pretty well. There's no dipstick, and you're not expected to need to check it.

-Chap

 

Actually, Toyota's saying to check every 30K miles.



I'd call BS on that though, doubt there's any need to check the level, barring evidence of leaks. On the other hand, I'd be inclined to revise "inspect" to "replace", at least at the first 30K. Or sooner: break-in seems to age it quickly, then it's more stable.