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Is this the only code that is setting or have you had P series codes also? Do you have the Vehicle Identification Number available?
Let me do some research on this and I will get back to you this evening. Has the dealership thrown any parts at this to solve the problem or did you spend the $600 strictly in diagnostic time?
How many miles do you have on this car?
Unfortunately this is going to get complicated very quickly. I checked the vehicle identification number and there are issues with a hybrid battery. The history shows that the battery was replaced at an aftermarket shop. There are other codes and I can go into detail but it would be easier to discuss this over the telephone. I have to step out for about an hour or so. If you would like to discuss this over the phone I will submit the offer now you can accept at any time or I can give you a lengthy description of what possibly could be going on here but to give you a definitive answer as to what the dealership is doing wrong is probably going to be difficult. Let me know how you'd like to proceed I will get back to you in an hour or so.
If the dealership is getting to wound up in the C1259 code then you need to consider getting the car out of there because they don’t know what they’re doing. Unfortunately not all dealerships have the diagnostic guys like myself in the back of the shop. A lot of them are just parts changers. There’s no way you should be spending $600 to have this diagnosed. This code and trouble that you’re having is very clear as to what’s going on. The C1259 code simply means that the traction control system is seeing a hybrid ECU malfunction. It by default will set this code every time. That’s not your problem! Your problem is the P0AA6 code. You have sub information codes 612 and 526. There was a P0A80 code set back in December 2015. At that time that is when they failed the HV battery and that code (P0A80) is usually pretty clear-cut that one of the modules or voltage blocks in the battery have failed. It is unfortunate that they did not offer you any assistance or give you the opportunity to contact Toyota corporate to see if they would provide some assistance in most cases if you have a good service history they will provide at least parts assistance which would’ve covered the cost of the battery. That being said at this point this code is very basic by that I mean the flowchart is very specific. Anytime you have this P0AA6 code in conjunction with both the 612 and the 526 sub information code you’re looking at insulation faults within the hybrid battery itself or within the system main relay. I don’t know what the aftermarket company did when they installed the battery whether it came with a new system main relay set up or whether was just the hybrid battery modules and everything was transferred over. The bot***** *****ne is the HV battery needs to be megohms tested for insulation leakage or faults. It is beyond me why the dealer has not been able to diagnose this and you should not be paying anything if they cannot diagnose it correctly. Typically this should be able to be done within a couple of hours of diagnostic time. Anybody that takes more than three hours to diagnose these particular fault codes does not know what the hell they’re doing. I have spent considerable time researching and trying to explain this to you in the typed format that we are working within. Please do not forget to rate the assistance that I provided to at three or higher so that I may be compensated for my time. If you would like additional information or need clarification feel free to reply and I will get back to you. The phone consultation offer will stay within your request information and you can activated in any time if you’d like to continue the conversation via telephone. Sorry to hear you’re having such a run around with the dealers and getting this resolved. Let me know if there’s anything else I can do. The bot***** *****ne is based on my perspective and research that I’ve done it looks like you have an insulation leak in the high-voltage lines within the HV battery in the back of the vehicle.
Let me know how things go.
Forgot to mention that the voltage blocks Are in order in the battery itself. The data list shows them within one or 2/10 of a volt of each of the modules which is normal. That's not the issue the issue is the computer is detecting high-voltage leakage in the HV battery that is where these codes are being generated from or being detected for.