In this case about the VIN, I happened to see a post on Japanese forum by anonymous poster (probably Toyota internal person).
affected VIN - Prius Gen3 forum

Ken@Japan

I've noticed that everyone is saying this is a problem with 2010 Gen III models. I have a 2006 Prius that I have been complaining about this same problem with the braking. It isn't as bad in dry weather but in the rain is when you notice it more. My son drove my car one day in the rain. When he brought it back he asked what the Hell was wrong with the brakes. He won't even drive the car again. When I took the car the last time the service guy knew exactly what I was talking about but again when I got it back it still does the same thing. I love my Prius but I hate the braking. I make sure I stay back aways in the rain.

It'd be helpful if you replied to the right thread on this as you don't have a 2010.

Since you have only one post, just joined today and I've driven my 06 Prius in the rain a LOT, I find your complaints questionable or about an entirely different issue. Perhaps you have bald tires and are hydroplaning, actually have bad brakes and not just the quirk that we 2nd gen owners used to?

Even though you have a Gen II, perhaps you can post exact locations where you hit the issue in http://priuschat.com/forums/gen-iii-2010-prius-main-forum/74199-poll-prius-brakes-problem.html as I did in post 10? By issue, I'm referring to light braking at low speeds, hitting something in the road such as potholes, rough roads, railroad tracks, etc. and having it feel like the brakes cutout briefly due to the switchover from regen to friction brakes.

It's almost a non-issue in terms of the net effect on the 2nd gens, IMHO.

Any chance of converting the relevent parts into English

Here's a question about all this. If you're in a typical light
to medium regen braking event and you put the car in Neutral,
you'll immediately get the hydraulic transition and likely the
usual accompanying "sag". [Do this when you've got plenty of
open space ahead if you don't know what I mean.] Does the "loss"
being complained about feel exactly like that?? Is it more
profound in the non-reflashed 2010 than in all the second-gens?
.
_H*

Here's the Google-provided translation, which is fascinating... I'm sure that this needs some work to reflect the actual meaning of the Japanese anonymous author.

"Nami says:
What happens if the brake and the other missing

ZVW30-0124257 (the first factory-made dam line 1)
ZVW30-1157314 (the first factory-made dam line 2)
ZVW30-5118118 (made by Toyota Auto Body)

Body or frame number of the above
The thing with the pre-measures"

lol

I'll repeat

Any chance of this in English?


I could tell you some funny stories about Google translator and it's erm, interesting translations.

translate.google.com??

great info danny

A translation...

"Regardless of whether the brake issue will happen or not -

ZVW30-0124257 (Tsutsumi factory - line 1)
ZVW30-1157314 (Tsutsumi factory - line 2)
ZVW30-5118118 (Toyota Auto Body)

Anything after those frame numbers has the fix in place."

Following is my best effort type of translation.
(Please donate $1.00 per word to me. )
-----
Title: Re: people delivered January or later, tell me about the brake lost
Poster: sorry in anonymous on this issue
date/time: Feb 4th, 2010, THU, 19:44
contents:
> Nami-san (Ken's note: reply to "Nami")

no comments whether the brake lost is existent or not

ZVW30-0124257(Tsutsumi plant no.1 line production)
ZVW30-1157314(Tsutsumi plant no.2 line production)
ZVW30-5118118(Toyota Auto Body production)

it is told that a vehicle body with above VIN or later
is already applied the fix
-----
Please let me know to correct my English, if you found any errors in my spelling, English grammar or anything.

Ken@Japan

I am supposed to pick up my Prius on Monday.
The vin # is lower than the ones mentioned here, so it will probably fall into the recall or repair.
Should I still pick up the car or wait for a new batch to get to the dealer. He has 3 in the lot, all prior to January production.
Any suggestions. Thanks.

this seems confusing. why can't we just press some magical button series on the MFD and see the firmware version of the car?

vin numbers are irrelevant because, as some have pointed out, toyota can't sell these anymore without flashing the upgrade, so you're going to have cars in the vin range that already have the fix.

posting a way to check firmware is going to be the sure fire way to tell if your car is affected.

Danny,
Thank you!

FYI to all,
Some Japanese users found their Prius VIN's were in the affected range, but the new software was already installed on them.
Toyota's answer is they did not track the VIN for the fix before January 27th, because it was the brake "feeling" update as one of many regular improvements, they thought.
When Toyota recognized it a critical one, they started to record the VIN after January 28th.

Therefore...

• since Jan 28th production, 100% of Priuses have the fix.
• before Jan 28th production, some of Priuses already have the fix.

Ken@Japan