Techstream not giving P0AA6 subcode

The car will only set a 611 to 614 subcode if it can determine where the isolation fault is. A footnote in the service manual says these subcodes are set the next trip AFTER the 526.

Since your car can't drive, here's something to try. With the ignition on but not ready, clear then check for codes. If it reset immediately then your fault is in the battery- a leak or the ecu. If not go to ready. If it codes immediately then your problem is contactors, cables, or inverter. If not shift to drive (or wait until the ICE tries to start.) If it codes now then you likely have a MG1/MG2 fault. Lastly try the AC.

This what the car would do when it sets one of the other subcodes, assuming that the fault wasn't bad enough to disallow operation completely.

Posted via the PriusChat mobile app.

 

In the first instance, I would NOT clear the codes.

Instead, attempt to make the car READY (even though it won't go READY) and then check the freeze frame data for the P0AA6 again. Hopefully, you will now see a second detail code in the 611-614 range.

 

Ok, I assumed that since you are using the Techstream software that you have been reading posts on this forum, and made further assumptions about how much you know. It's difficult to try and give a response when I don't know what level of experience you have, what tools you have, etc. The question I have right now is do you have the tools and knowledge to safely work on the High Voltage system on your Prius? It can be done IF you are careful and take precautions, but if you don't you can get hurt or damage things. ICE is Internal Combustion Engine.

The code you pulled is for a high voltage isolation fault. Normally the entire high voltage system has absolutely no connection (infinite resistance or complete isolation) to the 12 volt system or the metal of the car body. In your case one of the control modules has determined that there is some continuity or "leakage" from the high voltage system to the body- somewhere. Any repair requires working on the HV system, hence my question above.

Now dolj made a good point about the code. Do as he suggested- use techstream, go into the section for the battery ecu, check for codes there, and look for a little "snowflake" symbol on the same line as the P0AA6. That is freeze frame data. If that is there, click on it and see what info it gives you. Do that first then we'll cover erasing or clearing codes.

 

The key word here is ‘attempt’ as in press the power button with your foot on the the brake. It likely won’t get to READY, but it will cycle the start up process and hopefully set the second sub-code.

 

The first start after disconnecting the 12 volt battery requires you to push the power button twice with your foot on the brake. The standard one push of the power button will not make the car go ready.

Here's a dangerous way to check the battery for high voltage leaks without the sub codes. Wear gloves and use an alligator clip so you can handle just one test lead at a time.

 

Well, your untrained eye is misleading you. It's very common for the two end modules to run a tenth of a volt lower than the rest. It does not mean they are any better or worse than the others.

When modules start to leak their performance is not affected. So you can't use their voltage or capacity tests to find the leakers. The test shown in the video will help locate the leak. Unlike the battery in video your battery would hold a steady voltage between the orange plug fuse and the battery case. That will show how far from the fuse the leak is. With the battery out of the car, the orange plug installed, and the cover off you can measure for voltage between the battery case and different spots along the line of bus bars. The measured voltage will be small at the source of the leak and climb as you move away from the leaky module. Once everything is disassembled measure for voltage between the metal mounting bolt inserts on the bottom of the modules and the opposite battery terminal. Good modules will show near zero volts. Don't be surprised by seeing milli volts. Leakers will measure close the total module voltage. Leaked electrolyte can also spread to adjacent modules and create false positives.

Use extreme caution when working on your battery. Because of the leak the battery case (and the car body) is now part of the high voltage circuit.

To learn more about the leak detection circuit review this thread.

HV battery isolation question. | PriusChat

 

's way too slow
Be very cautious when you do anything- strawbrad is right on about .

If you want to try the hobby RC charger route, look at the discharge capability. Almost all (cheap) chargers only do 5 Watts per channel- that will take way too long to cycle a module. That can be 6-8 hrs per cycle per module. Each of the 28 modules might need 3-6 cycles. A better (and pricier) charger can discharge faster (more power)- 10W or 20W. I spent over $300 on equipment- multiple chargers and a discharger. Still took a month plus of spare time to do my pack. The modules have to be "clamped" together and cooled the whole time.

More/ better chargers are faster but cost more money. (the "recommended" unit was the Charsoon Antimatter 4x 300W, 4 channel so it can do 4 modules at one time. Listed on some China sites like Banggood- but that unit needs a separate high wattage 12V power supply. Availability can be erratic- when I checked in July it was 2-3 month shipping- so I didn't get that, now it says 2-3weeks)

Here is a super long thread https://priuschat.com/threads/gen-ii-prius-individual-battery-module-replacement.125588/. It generated as many questions as it answered. Having done it the "cheap" way myself, you might want to have a serious look at the Prolong grid charger system.