u/Prestigious_Drama902

Looking for some advice from anyone who's dealt with this before. 2012 Prius c 250,000 miles :

I lost all of my keys, and my Prius c sat for about 3–4 months while I was out of country . A locksmith came out, jumped the 12V battery, and tried programming some inexpensive aftermarket keys, but they couldn't get them to program. They said they were getting an ECU-related error.
I had it towed to the dealership. They also couldn't program a new key or get communication with the immobilizer/ECU. After some diagnostics, they told me they want another two hours of diagnostic time, but they're already saying I'll likely need a new immobilizer and smart key system. Their estimate is about $3,400 in labor plus over $1,400 in parts.
Before I spend that kind of money, has anyone experienced something similar? Is it worth trying:
Replacing the 12V battery with a brand-new OEM-quality battery?
Calling another locksmith that specializes in Toyota/Lexus all-keys-lost situations?
Sending the immobilizer/ECU out to be reset or reflashed instead of replacing it?
Could a weak or damaged 12V battery after sitting that long cause communication issues, or does this sound like the immobilizer/smart key ECU has actually failed?
I'd appreciate any advice or recommendations from people who've been through this. Thanks!

Looking for some advice from anyone who's dealt with this before. 2012 Prius c
I lost all of my keys, and my Prius c sat for about 3–4 months while I was out of country . A locksmith came out, jumped the 12V battery, and tried programming some inexpensive aftermarket keys, but they couldn't get them to program. They said they were getting an ECU-related error.
I had it towed to the dealership. They also couldn't program a new key or get communication with the immobilizer/ECU. After some diagnostics, they told me they want another two hours of diagnostic time, but they're already saying I'll likely need a new immobilizer and smart key system. Their estimate is about $3,400 in labor plus over $1,400 in parts.
Before I spend that kind of money, has anyone experienced something similar? Is it worth trying:
Replacing the 12V battery with a brand-new OEM-quality battery?
Calling another locksmith that specializes in Toyota/Lexus all-keys-lost situations?
Sending the immobilizer/ECU out to be reset or reflashed instead of replacing it?
Could a weak or damaged 12V battery after sitting that long cause communication issues, or does this sound like the immobilizer/smart key ECU has actually failed?
I'd appreciate any advice or recommendations from people who've been through this. Thanks!

I lost my only key , and A local locksmith attempted reprogram key and ended up deleting all of the key information and possible whipped the ecu. I have a 2012 Prius c

Now the dealership is saying there’s a problem with the immobilizer key computer , and that the Smart Key Computer Assembly may also need to be replaced.
Also said my 12 v is bad. But told me they need to do 3 more hours of diagnostics because they can’t figure out what’s wrong
are alternative solutions (like reprogramming) before replacing those and getting the codes from Japan

Cars been with Toyota for 3 weeks and no word yet….