Transponder, Smart System ECUs or key fob? B2557

First timer: I don't trust my local dealership. (what a way to start!)

Error code B2557
2005 Prius

The car seems to run perfectly but every so often the red triangle pops up with the (!) and the VSC light.
The car still runs fine but if I turn it off like that it won't start again unless I disconnect the battery
for 10 minutes or more. It seems that if I disconnect it for a short time those lights come on again on the
next drive but if I disconnect it overnight it takes much longer the next time. The lights are yellow except
the red triangle.
The tires are inflated to 36psi.

I took it into the dealership to fix the tire pressure modules or what's needed in that link but once they got
the car they ignored that, requested my second key fob and took 4 days to come up with an answer I don't
trust. To be fair the warning lights were not on when I dropped off the car.
Here's what I got from them:

Cause: B2775 sets when trying to start car using Smart System

Correction: Had customer bring other key to try, still same concern, follow DIAG chart for DTC, need to try new or known good transponder ECU, if that doesn't work need to replace Smart ECU, made est to replace transponder ECU -( $727.14, labor 4.0 $611.50. ) Smart Entry ECU ($1579.50, labor 1.5 $223.95)
Then the disclaimer...

That's $3,122.09 which basically totals the car. Could it just be the key fobs? They've quit working the
doors a couple of years ago. They did work in the past. I've had the car for 7+ years. Could it just be
the tire pressure instruments and the VSC?

My persistence is excellent which makes me a better mechanic than I really am. I'll try with provocation.

Thanks everyone.

 

I have not. I don't know anything about that but I'll study up on it now. I just put new batteries in the fobs. It didn't solve the problem. Thanks for the lead.

 

I need to correct that. The new batteries in the fobs did fix the problem with locking the doors but not with starting the car. Again, after "rebooting" the 12 volt battery I can start it with the key fob.

 

Nobody?

 

Thanks. It is in the out position. One of the silver fobs works for the doors and the fob slot to start the car. The other silver fob only works to start the car with the fob slot. I tried the chicken dance to see if I could get the second one back in shape with no luck. Neither have ever worked as keyless for starting or opening the door and I've had the car for many years, key button in or out. Would any of that cause the red triangle, the (!) and the VSC lights? I'm fine with the keys as they are but the problem turning on those lights disable the car until I unplug the 12 volt battery for 10 minutes or more. Thanks again. I sure appreciate the help.

 

The fobs are working as they always have. They do not drain its battery.

The 12 volt battery is a few years old. We leave the car parked for 5 months at a time with a trickle charger on it
and a friend comes over to drive it every other month. Good advice to get that checked. I'll do that asap.

We're only getting one code, B2557. The smart function never worked in the 7 years or so that we've owned the
car, and that's fine with me if it's not now effecting the issue I have now. I didn't even know the car had that ability
until this gremlin popped up.

Off to the battery store. Thanks!

 

I use a MacBook. I've read the mini vci won't work on them. I have a junk Dell laptop that the screen doesn't work on but maybe
I can cockroach something together with extension cords and an external screen. If so I'll get one of those cables even if the battery solves the problem. Thanks. Hey, I see below your post about turning up the HV battery fan. How's that done? It's always 85*F here.

 

Haha, I got the bigly-ist beater lap top. Windows XP. It did start up but I had the fire extinguisher ready. Thanks!

 

The 12 volt battery bench tested to be in good shape.

 

My beater laptop is dead. I bought a 32 bit. Dell Latitude D630 14.1" Laptop (Intel Core 2 Duo 2.0Ghz, 160GB Hard Drive, 2048Mb RAM, DVD/CDRW Drive, XP Profesional with Dell Reinstallation XP CD) $89 after shipping.
To be clear, next I need to buy the mini vci cable and then go online and get techstream software? Simple as that? Is it better to buy one with the CD? Links to a recommended cable and software?

 

For those wondering what the answer to my question, above, is, here's what I finally found on this site:

Order the cheapest mini-vci J2534 available for less than $15 shipped (Amazon, eBay, or AliExpress). They are all the same. Download the latest TechStream SW from the web and install it on a 32-bit Win 7 or 10 OS.

 

Quick question? I've downloaded the Techstream program. I bought a Mini VCI cord which came with a mini cd that
won't work on my computer. Is everything I need on the Techstream program or do I need to figure out how to get that
mini cd's data on a thumb drive?
Thanks.

 

My computer warned me not to open that link.