Prius no go! No codes found.

You need a proper code reader that will read prius codes. Most likely problem is your traction battery has failed again

 

how many miles on her?

take it to a dealer for the codes, or if you plan on diy, get mini vci and subscription to toyota tech info.

keep in mind, rebuilding the traction battery is a tricky process, not to be taken lightly.

 

Quick search in this forum ought to acquaint you with the usual suspects. Mini VCI is a common choice.

-Chap

 

P0AA6 means that you have a high voltage ground fault. The problem could be in the high voltage battery if you have a module leaking electrolyte for example.

The fault also could be anywhere in the system that has contact with high voltage: high voltage battery, system main relays, cable running from the high voltage battery case to the inverter, inverter, transaxle and air conditioner compressor.

 

An easy way to determine whether the traction battery is the problem is to use a voltmeter. The black test lead connects to the metal battery case. The red test lead is first applied to the positive output; then to the negative output. Obviously you have the battery case cover removed so that you can measure battery voltage prior to the system main relays. If you measure voltage at either point then the battery is the cause of the high voltage ground fault.

Should you find the battery is OK, then you will need a megohm meter so that you can test all of the components downstream from the traction battery. I suggest you subscribe to techinfo.toyota.com to obtain factory repair manual info and the exact procedures used to test, as well as safety procedures to observe.

 

I do not understand your question. If leaky battery modules are your problem, how does it help you to "find" them prior to opening the battery pack?

You need to open the battery case to facilitate a visual inspection so that you can see which modules show terminal corrosion. Those modules are the most likely to be leaking. The electrolyte itself is not going to be easy to see.

Your OP says you "rebuilt" the battery in July 2015. What did that rebuild entail?

Since you've logged 187K miles on the battery modules, if you want to keep the car, then it is time to replace all of the modules now - unless your idea of fun and entertainment is to be regularly removing the hatch trim and opening up the traction battery case to replace yet another module or two.

 

Since the electrolyte is clear, it is not going to be easy to pin down exactly which modules are leaking. Remove the bus bars and measure voltage from each module to the battery case.

Connect the negative voltmeter lead to the case. Use the positive voltmeter lead to measure voltage at the positive terminal of the module, then the negative terminal. Repeat this for all 28 modules.

If you can measure voltage from a module to the case, that module is leaking electrolyte.

The electrolyte is nasty stuff, so you do not want to get it on your skin, clothing, tools, etc.

 

Please define "rebuilt the traction battery back" as you stated in the opening post.

 

So if I understand right...your car/battery has 187,000 miles @ 11 years, you replaced 4 cells (of what 28 each?), did all the right PFM and got 10,000 more miles. I am all about maintaining cars and some slightly bigger machines , but...batteries and cells do have a shelf life so to speak. While admirable...I'm afraid that throwing a few new cells into the mix with much older cells equates your fix/s to short term limited deferral/s. It won't be long before you are doing this again. Now if you are OK with tearing into the pack on a routine basis and with your presumed skill...so be it. Me...I would just replace with a new battery if I was in it for the long haul. Respects from another wrench.

 

If you can do what you're doing, you can replace the battery yourself, so it needn't cost $4000.

exstudent has some good information re DIY battery replacement with a new one from Toyota.