C2309 DTC Code - Issue before buying? (P lock malfunction when parking) (Check Hybrid System)

So I found an excellent condition '12 Prius 4 with 70k miles solar roof asking for $11k. There's one possible issue however and that is a few weeks ago the car gave DTC C2309 . About 2 weeks ago the check engine light came on and gave the p lock malfunction message. I believe this made it impossible to turn the car off which also drained the 12V battery. A quick search on google shows this to be the only thread about this: P Lock Malfunction HELP! | Page 2 | PriusChat and as @Rebound states It's not a common code:
"Open in B+ Circuit"
- Transmission control ECU assembly
- Auxiliary battery
- Wire harness or connector"

Apparently the ECU was the issue, & the 12V battery was already replaced. IGCT Fuse #2 is dead. All other systems seem to be fine.

I am trying to determine what may have caused this, what possible damage may have occurred, and what issues in the future may develop pertaining to this if any.

Seller says that blowing compressed air on the ECU assembly made the problem go away, but it's not a guarantee it'll fix the problem. Toyota said they can replace the ECU for $1460, but seller informed me that the part is cheap on eBay and his mechanic can install/reset codes for $300.

I am mainly curious to know if 1) there are/is any more possible damage 2) if the car is a good deal at this price 3) if the ECU assembly being replaced will make the car safe/reliable? I am mainly concerned about after purchasing the car, the check engine light coming back on, and more problems happening, the car becoming nonoperational, or not able to be repaired. Should I skip this car, or should I ask for a lower price & if so how much?

The seller has been and is honest and fortcoming about this potential issue, & has regularly serviced the car every 5,000 miles.

Thank you in advance

 

The parts from eBay are genuine Toyota. The Toyota dealership price gouges like crazy – often by a factor of 5-10x– but the question is if replacing the ECU module is enough. I'm not sure if Toyota is price gouging on replacing this ECU - but they seem to overcharge like crazy for everything.

The car went through a Toyota PPI/multi point inspection (by seller) and the rest of the car is mechanically fine. I don't know much about the ECU and what it exactly does, but yes, I agree there's an element of risk involved with this. The price is I believe offered at about $1500 lower than what it would have gone for if it didn't have this issue.

The problem also is I need to get a car soon, & it's hard to find a Prius 4 with the top trim in good condition, good miles, etc. at a reasonable price. The ones that do exist often tend to go for more than what a '16 gen 4 touring would cost incidentally.

 

Out of curiosity why do you dislike the 3rd gen? Do you think the 2016 is far better than the 3rd gens? It seems to be better than the other competitors that have even more problems. It seems the problems of the third gen are largely surmountable except for brake actuator, and AC compressor. EGR assembly, oil burning, and inverter seem to be relatively simple problems to treat or fix.

 

But couldn’t it be said that every other manufacturer is significantly less reliable? The hybrid tech is intrinsically more complex than say a corolla or rav4.

 

I think you're right that the modern car is significantly more reliable as far as transmission and engine goes versus 20 years ago +. I do think the Toyotas and Hondas of the 90s were really at the top of their game over American/German counterparts - but now across the board engines/trannies are overall decent... except for turbos. Toyota the only that's been avoiding turbos which are high stress/high pressure which has been used for the sake of higher power at lower cost.

There are some makes though that are just terrible in general - the BMWs for instance.