Gen 2 Prius P0AA6 battery leak confirmation

[@mytubeyear2009]

Used this technique today on a 2009 Camry HYBRID. Worked perfect. Read 57.70 volts without change (has code P0AA6 with detail code 612). Tested theory again on functioning 2007 Prius. Counted down from 27 volts to zero just as hoped. Excellent test! Thank You.

[@phb_3835]

-612 is almost always the battery. Holding voltage per this test is solid confirmation. The frustration occurs when you get a -526 only with no second detail code. This check gets you confidence it's the battery. Glad to hear it worked for you. I use it frequently. It helped me resolve a -614, which was triggered by a leak on an END module connected to the relay, which I had never seen before.

[@mytubeyear2009]

@@phb_3835 I assume the amount of voltage read on the dvom indicates the location on the battery pack that the failure is occurring?

[@phb_3835]

@@mytubeyear2009 Correct. It will be X modules from the safety plug based on the measured voltage. Since resting voltage can be pretty squirrely, it's hard to say how much, but 8V gives you a good guess. Regardless, you can almost always SEE the leak via staining at the bottom case and/or the bolt in the bottom of the module. If there is no visual evidence, you can narrow it down by pulling the bus bars and measuring voltage from each module to case.

[@mytubeyear2009]

@@phb_3835 This is the first Camry I've done, but usually the Prii (Toyota's plural for Prius 😂😂) code up with bad cells (low voltage) and are easier to diagnose. This Camry cell voltage was Fairly even across the board. One of techs I work with came from Toyota and thought this confirmation test was awesome. I do too. When I get the battery out, I'll see if I can identify the failed cell. Thanks again, John.

[@phb_3835]

@@mytubeyear2009 For a P0AA6 failure, it's rare that a module has a failed cell. Voltages will usually be very tight. Pinpointing the module always requires opening the case and checking EACH module's voltage to case with the bottom screws installed and bus bars off. Make sure you leave the bottom screws in. Without them, you may not be able to find it in rare cases. Another quick trick is to check the main leads to ground (on the hot side of the relay) with safety plug out to identify a module that may have failed where the safety plug attaches. PLEASE EXERCISE EXTREME CAUTION AS YOU HAVE VOLTAGE WHERE YOU SHOULDN'T.

[@liberty9348]

Thanks for making the video. I got the code 526-612 from the Stealership. They charged me $135 for the code. Wanted another $560 to "diagnose" the issue further (because they had to access the battery, which took me 15 minutes to get to). This test saved me $560 and a ton of electrical testing. THANK YOU. Mine read a very steady 137.2V. Seems like my leak is around cell 17. Will strip it down tomorrow, repair/replace and get this Prius back on the road. Thanks a million.

[@kayali8842]

Did you fix it? I have p0AA6 fault

[@liberty9348]

@@kayali8842 yes I did. I replaced the cells which I bought off eBay for like 30 bucks each if I remember correctly. Bought new little oval tab things that all the nuts go on to connect all the cells together (can’t remember what they are called). Put back together and it worked. All warning lights went off.

[@kayali8842]

@@liberty9348 has it stayed off since you replaced? Becouse when you disconnect the 12v battery the p0AA6 code clears and takes a week or two to show up again

[@liberty9348]

@@kayali8842 I actually didn't disconnect the 12v. Instead I just unplugged the WHITE kinda long block plug to the 12v and replugged it after a minute and all the lights went away and stayed away. Everything works perfectly.

[@kayali8842]

Yes I just found the white plugs that connect to the 12v battery, another question is what seething did you set the multimeter to? Thanks

[@PaintSlinger99]

This video has helped me twice thanks

[@DukenukemX]

I'm getting P0AA6 612 and did the same test to find ~63 volts leaking, but when I remove the battery and do the same test then the multi-meter shows nearly zero volts. I put the fuse back btw. The only wire that causes the voltage to show is the large wire that might plug into the battery ECU. I'm not 100% sure it's the battery ECU but it has the largest plug. Nothing else is hooked up to show ~63 volts.

[@phb_3835]

With the battery out, you should be able to check for voltage between the case and each of the main (+) and (-) terminals.

[@giorgioye]

In my case Toyota techstream gave me P0AA6-526 error. Torque pro shows me all modules are around the same voltage it seems to be no leak and in good health. But with your method it bleeds very slow from 12/13 volt to 9/10 and sometimes it rise up and never go down to zero. Could it be considered a leak of battery and do I need to start thinking about change battery instead of cleaning and drying wet cables/connections?

[@dosal310]

Did you fox the issue

[@giorgioye]

@@dosal310 i bought a battery from junk yard and problem was resolved

[@motorcyclesplusparts7309]

Hey thanks for the video!!! But i only got about 30 volts from that bold to the case and it did not trickle down Any advice on what i should do next? Seams as if i have about 4 bad cells???

[@phb_3835]

Will your car start and DRIVE, or will it only go into Neutral or Park?

[@PaintSlinger99]

Mine is doing the exact same. Holding a 30.8 Volts. The vehicle will not go into Drive or Reverse. My codes are P0AA6, C1259 HV System Regenerative Malf, C1310 Malfunction in HV System, C1378 Capacitor Comm Circuit Malf. Anyone have this happen? Is it a bad cell? cells in HV batt?

[@skoda110]

LoL this video was posted on my birthday...anyway, I bought 2009 prius 3 and battery seams to be rather weak at about 6-7 modules. Wonder which method of bringing this to life would be best. 1st i disconnected all cells and tested them using h1 bulb and measured voltdrop and time. Should I cycle each up and down and test again replacing weakest ones? As you've said at one video's comment the modules at the sides are better than middle ones. Can I put them with weaker ones in pair? Please help me. New battery cost too much for me. I can afford used one or single cells. Kind regards Michal

[@debendragurung3033]

I have sadly come across the same issue. I have a 2005 Gen 2 200K miles.the issue cane after changed the Block 11 hybrid modules. The car was driving even though the dash kept showing red triangle. Ran the tech stream minivici and showed the Block 11 low voltage error. Now after I changed the module it just won't engage to Drive or Reverse Mode and only on Neutral Mode . The Ready mode stays on the Dash for a second or two and goes away. I can also the clicky sound of thr relays. I don't know how many am I supposed to hear but I can distinctly tell there were two or more. I have changed two modules on block 5 - 4 months ago and the car was running fine.

[@phb_3835]

The ready light behavior you describe is very irregular. In 300+ Prius maintenance events, I have never seen anything like that. Ensure 12V is healthy with load test and make sure all 12V connections are tight. Recommend you run full health check with Techstream.

[@stwicks77]

I get code P0AA6-305 (Autoland Scientech scanner, 305 isn't even an option..Lol) So I did your test, my results are voltage starts at 45-46 vdc then trickles down and stays at 36.17 vdc after about 30-40 seconds. Safe to say I have a leaking HV batt? In theory, if you unbolted the HV batt and made sure nothing was touching the vehicles ground, it should not set code P0AA6? Not that would be a fix, just trying to understand how this works.

[@phb_3835]

No such thing as P0AA6-305, but Impressive that it can read a P0AA6 at all. Holding any significant voltage is highly indicative of a leaking module (likely 4-5 modules to the left or right of the safety plug connections). If you break the ground to the chassis, you also break the ground to the the HV battery computer, and the car will refuse to start (HV battery case MUST be grounded to chassis to start). For a temporary work-around, you should be able to clear the code with the reader OR disconnect 12V for 60 seconds/reconnect and resume driving until the code is detected again. You will be allowed to finish that drive until you power off. After which the car will be disabled again and you repeat the reset procedure. Only fix is to replace battery or replace leaking module. If you tear into a battery with a P0AA6, the battery is a major shock hazard as any terminal may provide voltage to case.

[@MLK.PaNoRaMa]

Funny I get exactly the same code with 305... Same thing I have to reset code by phone OBD2 plug then Start the car every time... Did I end up fixing the problem what was it??

[@MLK.PaNoRaMa]

Set the multimeter on voltage test over 200v?

[@debendragurung3033]

OK I did the test and the voLtmeter only registered 6Volt max and trickling down . On the Techstream all the battery blocks are above 15.5 V volts. What could be the problem? During the procedure I had disconnected the -ve terminal of Auxiliary Battery.

[@phb_3835]

The test can be unreliable if the leaking module is on/adjacent the safety plug. Since you are familiar with the battery construction, open the electronics cover and check for voltage between the (-) and (+) terminals (under the white covers) and the battery case (check each terminal to case separately). Ensure safety plug is removed AND exercise extreme caution as voltage may be lethal.

[@debendragurung3033]

@@phb_3835 OK. I will try and measure voltage across the -ve and positive terminal under white caps. In doing so shall I unplug the orange service plug or leave it as it is. And I ran the Techstream again and I nolonger see the P0AA6 fault. But it there has the P3004-131. Any idea what that is??

[@tim8532]

I have this error, I also checked the voltage, it stands, so I have a leak possibly, but obd test shows the same voltage with a minimum difference in the cells, which means the normal. Сan it be that the computer shows that the cells are ok, but at the same time they have leaked?

[@phb_3835]

P0AA6 with a leak in the battery will not show in block voltages or any other parameter discrepancy. This isn't related to block voltages. This is a HV system voltage differential to chassis ground that shouldn't be there. The HV system is isolated from chassis ground. If you measure a voltage that holds in this test, you have a leaking battery module.

[@mytubeyear2009]

I've got a 2008 Prius, 112k miles that was towed in, no start, died at low speed. Codes are C1259, C1310-156, P0AA6-526. The first time I cleared the codes it started and ran (idling in shop) for about 10 minutes then shut down. All codes came back. Now they won't clear or start. I did the voltage test at the plug and get -7.00(?) volts (negative dc voltage) that holds - no fluctuation. If I swap the mm leads I get +7.00 volts. I double tested my meter on a 12v battery, it read properly. Any ideas would be helpful. Thanks

[@phb_3835]

Per the description, "If it HOLDS voltage, you have a leak." You have confirmed you have a battery leak generating the P0AA6-526 code. The C1259 and C1310 often occur with a battery failure.

[@benc1927]

@@phb_3835 I also have P0AA6 with C1259, C1310 but also C2318 Transmission Control. Do I have a leaky battery ?

[@brandynwebb]

I'm getting 144V... (lever up, but NOT slid down). I feel like I'm missing something obvious here. Thoughts?

[@brandynwebb]

@@snoobler It's a Gen 2, which looks to have 19 * 7.2 V nominal on one side of that fuse, so could easily be 144V. Under what conditions should that bank be grounded to the chassis at the other end (which appears to be what I'm seeing)?

[@phb_3835]

HV system is isolated from chassis ground. If you're measuring 144V constant, one of the two modules at the passenger end of the battery has leaked and is creating HV potential to ground. If you measure ANY constant voltage between plug and ground, you have a module that has leaked and triggered P0AA6.

[@brandynwebb]

@@phb_3835 Noted, thanks! [Now if I could convince Greenbean battery of this -- they installed this battery and it failed immediately (first time I tried to drive it after the tech's test drive, it would not Ready), but instead of making good they want me to tow it to a dealer and pay to have the sub-codes read before they'll honor the "warranty" even though they never installed a working battery to begin with...]

[@phb_3835]

@@brandynwebb While I'm highly confident that this tests is accurate (Phoenix sees more battery leaks by an order of magnitude), it is not recognized as an acceptable means of diagnosis. The Toyota instructions for P0AA6 are 18 pages long. Unfortunately for you, GreenBean has always been very clear about the requirements for their warranty: greenbeanbattery.com/our-warranty/ - "All suspected warranty claims must first be diagnosed by a repair shop or a Toyota dealership. The following information must be provided by the repair shop or dealership: Diagnostic trouble codes for the Hybrid Control ECU Diagnostic trouble codes for the Hybrid Battery ECU Diagnostic trouble codes for the Engine Control ECU Upon review of the repair shop/dealership diagnosis, and determination of a battery failure within the warranty period, Green Bean battery will replace the failed battery in accor- dance with the warranty. Green Bean Battery will not reimburse for diagnostic expenses or towing associated with any warranty claims. No warranty replacements will be processed without a diagnosis, and diagnostic trouble codes from a repair shop or dealership. No exceptions."

[@debendragurung3033]

i am sorry but what is vm probe

[@phb_3835]

Voltmeter probe

[@debendragurung3033]

@@phb_3835 haha .llol