Prius went into limp mode on freeway, IPM failure

Had you done the recall tideland mentioned?

 

is it a recall, or tsb?

 

The software update to protect inverter was in March 2014, I see a number: SOSH-230-1A.

 

was it a recall, or tsb? there is a difference, in the u.s. anyway.

 

yikes! not something to ignore, like my airbag recall, i guess.

 

E0E re-flash was a recall, Feb. 2014, designed to lessen current on the IPM under high load. Problem is, by 2014 there were plenty of Gen 3's that had endured plenty of hammering prior to the re-flash. So we still see plenty of IPM failures to cars that have had the recall. I wonder about mine every time I've got the pedal mashed on the floor, which is more often than I like to admit. I had almost 90k on my 2010 when it got the E0E. Thus the warranty enhancement, ZE3, 15 years/unlimited miles on the IPM.

 

what would they have to replace to eliminate the problem, is it expensive?

 

They don't replace anything physical, just reprogram the acceleration, so there's not a sudden/heavy load on the inverter, make it less abrupt.

 

The short answer to your question is they would need to replace all IPM's in Gen 3's manufactured before the E0E.

I'm no EE but my understanding is that the IPM is just a circuit board, mainly consisting of 3 good size capacitors, that lives in the inverter. With the original software spec, current under high load is enough to crack leads, or a lead on these caps. When this happens the car goes instant game over. Again, this is my dumbed-down idea of the goings on but I'm pretty sure it's in the correct solar system. With the ZE3, they are replacing just the IPM, not the entire inverter. So it begs the question could they have just replaced IPM's at the same time as they did the E0E in the first place? And the answer I spose, is sure, if they'd been willing to pony up. Instead they kind of leave you with an IPM that may or may not fail down the road. Post E0E, less current is fed to the IPM. If you haven't previously fatigued your IPM to the point where the new, lower current load can finish it off, you're ok. For myself, with a car that saw 4 full years and 90k miles before the E0E, it's easy to wonder if I have a compromised IPM. People consistently tell of terrifying IPM failures, so it does seem to be a real safety concern.

 

agreed, seems like nhtsa dropped the ball on this one.

 

I really get a kick out of Mendel's politically correct statement, "makes it less abrupt". The fact of the matter is that it makes it a slug.

 

Any worse than other cars that go into limp mode? Or snapped timing belt mode?

BTDT, on both. Uncomfortable, but not a disaster unless an aggressive driving culture makes it into one.

 

I didn't notice any difference in acceleration, though I pretty much always take it easy. What I did notice: it seemed to sliip into electric-only a bit easier. My wife mentioned the same thing, and I hadn't said anything about it to her.

 

Good point, fuzzy1, and I'm with you in that sudden vehicle shut down isn't a huge deal to me personally, being a very comfortable driver. But to the driver for which it brings on panic, things could go sideways if quick and correct navigational decisions need to be made under stress. This could no doubt be compounded by your "aggressive driving culture" point. In that respect, I think it was irresponsible of Toy to not just throw new IPM's in as they performed E0E's to generally eliminate the IPM as a safety concern.

 

Before the software update, if you travel on 2-lane roads, for example, and needed to floor the accelerator to pass a vehicle quickly, the acceleration was instantaneous and surprising for a Prius.

After the update, when you floor the accelerator there is a definite lag with no acceleration and then a steady rate of acceleration. The initial pause will catch you by surprise if you were use to the instantaneous acceleration.