Hybrid Battery going bad?

The second one sounds more likely. If it shows +/- amps into/out of the HV battery, I'd say so. In any case, you've got nothing to loose. Give it a try.

 

Nope, when the engine is not running the display will also be 99.9 MPG, because that's simply the largest value that the US (MPG rather than L/100km) energy monitor screen can display. Given that the (fully warmed up) idle fuel consumption is about 0.2 gal/hr, it follows that an idling engine can not be distinguished from zero fuel consumption (true glide) at speeds above about 20 MPH in the US models (as both will max out the display at 99.9 MPG).

Here in Australia where we use L/100km we can display much lower levels of fuel consumption (and distinguish them from zero) than is possible with the 99.9 MPG limit of the US models. For example if my engine is idling while I'm gliding (stage 3a) then I sometimes see fuel consumption as low as 0.8 L/100km, which corresponds to nearly 300 MPG (US).

 

While I agree with everything else you have said, the behaviour of the MPG (and also, I imagine the km/l) display is as I said. I thought it was strange at first but when you think about it, it is a way of expressing no fuel being used even though in mathematics you cannot actually express some miles divided by no fuel used -- you get a divide by zero error, so the programming intercepts and displays zero anyway. Any time a l/100 km display shows zero, in the same circumstance so will a MPG (& km/l) display.

[EDIT] Actually having given it a bit more thought, you are correct until the car stops. Then it goes from 99.9 to 0.00.

Sorry, jumped the gun.

 

Yep that's right. When you're at rest the maths is basically "0 divide 0", which is indeterminate but it displays zero. When you are moving however it is "non zero divide 0" which is infinite, so it just displays the maximum it can.

BTW dolj, I was just wondering what system you guys use there in NZ. Do the NZ Prius's use km/L (like in Japan) or L/100km (like here in Australia)?

 

l/100km like in Australia, in fact I think we get exactly the same cars here as the ones for Australia.