Prius cut out whilst cruising, lost drive

What was the fault code? P0A93? Also have the 12V battery checked (can replace with Optima YTS 2.7J)

 

my daughter has the same year and mileage, all the best!

 

It would help us a LOT of you could please post what the codes are, before paying any more money.

 

I've had that happen when you hit the "P" button while driving. But it should reset with a power off.

It also happened to me RIGHT after a software update at the dealer, to eliminate any possible "throttle malfunctions". My dealer towed it 3 miles back, reprogrammed and didn't charge me a dime. (Thank you Tracy Toyota).

 

Can you point us to more details on this "software update", specifically what it said on your receipt? I'm unaware of any for my 06 which was bought new.

 

This is normal when the technicians have no idea what is going on. You need to press them for all of those 9 error codes. No need for them to explain each one -- we can translate.

Now, here's what could have happened: The prior inverter cooling pump service was done incorrectly. This may not show up as a problem until a long drive in hot weather. Once that code sets, the car will still drive, but there will be no air conditioning, and the computers and power steering run entirely off the small 12V battery. It is typically a matter of minutes before the high current drain makes the 12V voltage sag underneath 10V or so. At that point, sensor signals begin to fail, because they fall below required operating voltage, and codes get set. Very shortly thereafter, the car will cut power completely.

IF this is what happened to you, normal procedure is to (1) recharge the 12V battery overnight (2) reset all codes (3) recalibrate any lost zero point calibrations (4) fix problem in inverter cooling system. If you can prove that it was a problem with the inverter cooling system, then you should not have to pay for any of this, assuming that it is at the garage that did the prior work for you.

 

It's very easy to not get all of the air out of the system. My dealer had to do it twice. If you're lucky it will be that simple.

 

Yes it seems that we've seen quite a few cases like that reported here now, where there's a problem fairly soon after the pump recall has been performed.

Does anyone know how "failsafe" (or otherwise) is the inverter thermal protection? It seems that in some cases it protects itself ok but in others there is real damage done when this happens.

 

Virtually every story is, Christmas tree -> no A/C -> more lights -> shutdown -> tow -> fix. I'm not aware of others where there was real damage done? Since Ohmic heating is quadratic in current, just scaling back by half cuts the heat load by 3/4.

 

I'm curious if a simple turbulence check in the inverter coolant tank would show the problem before it goes into failure mode. In other words, does having air bubbles in the system stop flow completely?

 

Yep I've been wondering exactly the same thing. It would be nice if there was a simple way to test if it was done properly.

 

yes, if you have the proper fluid level, and you see turbulence in the tank, then it is working. If the fluid is placid, then the car will code P0A93 when the inverter temperature gets hot enough. It is really that simple.

 

Potentially basic question from mechanically green Mike: Does that mean that if there are air bubbles, you'll never see turbulence in the coolant from the moment the work was done, or rather that you would at first, but when the air bubbles work their way to a certain part of the system, *then* the turbulence would stop?

 

It would be an air bubble at the inverter pump impeller. That would happen within the first minute or so of operation. That's one reason why applying partial vacuum at the reservoir cap, or perhaps the bleeder screw, would force the air bubble to come out.

 

I hope they do warranty it, since over here it is usually part of the powertrain warranty (5 years, 60,000 miles). But the gearbox explanation smells fishy.

Did they give you the trouble codes?

 

This diagnosis seems reasonable given what you have posted. In the US the transaxle is covered by the 5 year/60K mile powertrain warranty. I doubt that the UK warranty coverage is more favorable.

If it is confirmed that the transaxle is the problem, you might inquire into the availability of a salvage unit that your dealer could install. Hopefully a good used unit is lying around and available at a reasonable price, waiting for your dealer's call. Good luck.