Prius III (2010) recall - which part?

inverter diodes. there's a thread here if you search. see the thread 'inverter ipm, 15 year warranty.'

 

Here's a link to one of the discussions on the topic: Toyota to Recall 1.9 Million Priuses to Update Software | PriusChat

It's a major, expensive repair. Essentially, the inverter gets replaced. The failed part is buried in the bottom of the inverter (the transistor/diode assembly), and it's built with what appears to be clean-room techniques. We're talking major power transistor die; that is, not transistors in cases, but transistors directly mounted to a fairly hefty heat sink.

Best guess of the problem: Hard acceleration 2nd order effects cause a temperature differential between a pair of power transistors and an underlying heat sink. If this is severe enough, cracking develops under the power transistors in question. This can eventually cause one or the other of these transistor to break free, causing arcs and sparks. If you're lucky, the car can limp to the side of the road. If you're not lucky, when this happens, the car stops dead. Which is why it's a safety recall.

There's a recall out that, apparently, reprograms the engine controller to cut down the rapidity of the onset of power from the motors, thus getting rid of that second-order-effect overheat. People report a slight decrease in acceleration as a result, although the amount of decrease appears to be close to being in the noise. Mixed reports on whether it affects gas mileage; apparently, not really. A certain number of people report that they had to get the update installed twice; the first time, the update reulted in badly driving cars. A second go-around seems to fix things.

There's been a few cases where the inverter failed after the update. This is thought to be due to cracking having started before the update was applied and just failing to completion after the update. It is thought that this is why Toyota has been extending the warranty on the inverter in a number of cars.

Haven't heard of anybody trying to do an inverter update themselves. If you had a local mechanic with access to Toyota's repair manual, the tools, and the software, said mechanic might be able to do the swap.

KBeck



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