Went out to look at an '08 Prius today with 254,000 miles today that is for sale locally. First question: Problem is negative battery cable needs to be disconnected and reconnected in order for the car to start initially. It does show a P0AA6 code, although shows all four bars on HV battery charge even under load most of the time and drives very well. HV cells were tested by seller and showed to be within normal spec and no leaks. Second question: what would you suggest offering for a car in good condition with said issue/issues?
Code is P0AA6 – P-zero-A-A-six. Once the code is cleared (which happens when you remove the 12 V power) the car will drive normally for one drive cycle but the DTC P0AA6 returns during the drive cycle. When the car is turned off, it will not restart unless you do the battery trick– so you rinse and repeat. Eventually, bad things could happen to the battery when the bad module(s) give(s) up. It looks like the ECU disagrees with the previous owner. I know who I'd believe. The thing with leaking modules, it can be very hard to spot visually. Chances are you will be able to find the leaks with a mega Ω meter ("megger"), or even a regular multimeter looking for voltage to the case. When you have leaking modules, the leaking module(s) need to be replaced and the case needs all modules to be removed, the case scrubbed clean of any electrolyte and thoroughly dried. All modules should be cleaned thoroughly as well. Then the good modules plus replacement modules need to be reinstalled in the case. $500, maybe $1,000.
I believe a P0AA6 has a few subcodes possible, so it's not necessarily the HV battery causing the insulation problem. Could be the transaxle failing or inverter failing or the AC compressor, or the HV cables damaged under the car, etc. Getting the subcode is the first step toward determining which area of the car is triggering the code. The costs of repair are obviously vastly different depending on the source of the trigger.
Thanks for all the great input. I really need access to the Techstream software it seems. Seller owns a small shop and is representing one of his customers as the seller. He does not have too much knowledge about these Hybrids and doesn't seem to interested either. I threw an offer of $800 at him and he responded with "I have $1,000 offers". Then proceeds to raise the price $700 on his listing in less than 24 hours.
