Pls help- engine light on - low horse power - p0a7a diagnostic code

inverter pump or icm module? have you had the inverter recall update performed?

 

Yeah, that sounds like @GrumpyCabbie's experience. Beginning of the thread:

Possible Gen3 Prius Transaxle Failure at 70,600 miles | PriusChat

Diagnostics confirm it was the inverter:

Possible Gen3 Prius Transaxle Failure at 70,600 miles | Page 2 | PriusChat

 

I should have mentioned: regardless of the title, it was inverter failure.

 

What struck me as similar was that the failure happened under hard acceleration.

That's what the recall was about: Toyota found some soldered connections in the inverter were fracturing with the sudden surge of electrons under hard accel, so they revised the programming, to make the surge more gradual.

Maybe yours, being 2012 had the patch already, from the factory. Regardless, I guess it can still fail: changing the software is a balancing act.

Definitely step one is a dealership visit.

Where in the world are you btw?

 

i forgot about that article. seems to be pretty rare, but definitely something to be aware of.

 

Inverter................... I know first hand.......

Had the update at 169,000 blew at 196,000
They replaced a circuit board
Was going 35 and barely stepped on the gas and then the christmas tree..... and 1100 miles from home

 

One part of that story that I don't think we mention enough is that, per the defect information report (third page, last paragraph), it really appears to be overfast cooling of the solder joints leading to the development of voids.

There's an amphibolous phrase in there (probably thanks to Japanese ⇒ English translation), "if the vehicle is not operated for a long period of time after the IGBT ... reaches its maximum temperature." One reading could be "if the vehicle sits unused for a long time after", but it could also mean "operation of the vehicle isn't continued long enough after", and my money is on the second reading. That would suggest some hard acceleration (or deceleration with regen) that isn't followed by a long enough interval at moderate power for the solder to cool down gradually and anneal nicely; it cools down too suddenly, and gets like refrozen ice cream.

That has implications for what Toyota's software patch really did. We don't really know, and everybody seems to want to assume it had to be a cap on hard acceleration to limit the heating. I'm pretty sure if I had been a Toyota engineer working on that issue, I would have been much more interested in tackling it from the too-sudden-cooling end. I don't think it would be very hard to stretch out the cooling period after a peak power event, just by temporarily keeping the current a bit elevated and phase shifting to reduce the power factor. Seems like that would aim more directly at the crux of the issue, and could do it without requiring a cap on the peak power.

I guess it's conceivable I could have thought of that and a roomful of Toyota engineers didn't, but I bet that's so not the case.

 

I didn't get charged for anything.....