P0A08 error code

Well, a final update.

I worked my way through the Toyota 20 step Inspection Procedure for diagnosing the P0A08 DTC and the DC-DC Inverter Converter was proven to be the problem. The Inspection Procedure was well documented, except for one error (on how to test resistance of the fusible link block at the 12V battery) which a more electrically savvy friend clarified for me.

I had already purchased a used DC-DC Converter Inverter Assembly off of ebay a few weeks ago (with a 6 month guarantee, free returns and free return shipping) just in case I did need to replace it. I had looked around locally, and could have gotten one for less than the $300 it cost (with tax), but local salvage yards don't even pull the part until payment is made (in person) and that would require me to make a second trip the following day to actually pick up the part. I would not even have been able to view the part while still installed in the donor vehicle. And, driving over 100 miles roundtrip, twice, through downtown Houston freeways was not appealing either. With a reputable ebay seller, I had a much better idea of what I would be getting. And the 6 month guarantee and free return shipping were the best I found anywhere.

A video I had found by CarHub showed the quick and dirty way to remove the assembly, complete with 4 letter language, but it was helpful in showing me what and how to remove, and the general sequence. I watched several times and made a written list of the steps involved. For my removal, I took my time, had on insulated gloves when necessary, and bagged and labeled bolts and clips at each stage. I did remove the coolant a little differently by simply wicking out as much as I could, using a long strip of an old chamois cloth. There was still some drippage after hoses were disconnected, but a drain pan would not have caught much anyway with all of the obstacles between the reservoir and the drain pan.

After old unit was removed, then took a little more time to transfer all but one of the metal attachment brackets from the original unit to the newly purchased unit (one rusty Phillips head screw wouldn't budge). Not sure of the mileage of the donor vehicle, but suspect it came from the northeastern US where the seller is located, based on the rusty condition of all of the brackets. And, swapped out the cover with my original cover, also in better condition.

Installing the new-to-me unit was just reverse of how I removed the old one, and only took about 1.5 hours (I work slowly). Filling the coolant reservoir, and researching how to bleed out any air bubbles, took almost as long.

Before powering up vehicle entirely, ran another Full Scan. Total of 14 DTCs found (4 different codes were: P3056, P0A09, P3000, and P3140) with all 4 showing up at least 3 times and with either a Current, History, or Pending Status. DTC P0A08 was not found. I had expected some DTCs to be detected. Sometimes the warning lights that appear will go away after a few start attempts. These did not. I had kept the 12V battery connected during the entire removal and replacement process, as the Inspection Procedure called for putting vehicle in IG-ON state for one test. The Toyota Removal Procedure DOES call for disconnecting the negative cable from the 12V battery before removing the Service Plug Grip, so I had missed that step. I now removed both the positive and negative cables from the 12V battery, waited about 30 seconds, and reconnected them. Voltage at battery was 11.56V. Put vehicle in IG-ON to do another full scan. No DTCs detected this time. Started vehicle and put in READY mode and all was well. Got voltage reading of over 13.5V at 12V battery indicating battery was getting recharged. Metered cable leaving DC-DC Converter with clamp-on meter and had high current flow of over 50A with several 12V items on (headlights, fan, defroster).

Finished re-installing all of the "trim" pieces that had to be removed to access the converter inverter, the 12V battery, etc. All put back together, and hope all continues to do well.

Thanks again to all who helped guide me to this conclusion, and hope my learning experience will be of some benefit to other owners.

 

Where did you find the 20 step inspection procedure for p0a08? Just had two dtc's for that code pop so I am trying to work my way through troubleshooting. Hopefully I dont have to mess with the inverter, but my dad and I tackled the abs module a few years ago so we can DIY it if needed. Thanks and glad you figured it out!

 

I just Googled and searched until I found this site: https://www.allcarmanuals.com/factory-service-manual-284-Toyota-Prius-XW20.html

It may say 2003 - 2009, but I think it should say 2004 - 2009. I downloaded the entire folder, then selectively printed only the pages from the chapters I needed. The P112 Hybrid Vehicle Control - HV Chapter has the inspection, removal and installation procedures.

When our ABS went out about 2 years ago we had it replaced. In the process of my removing the DC-DC Converter Inverter, the three bolts that held it in place were only started by hand and not tightened down, so it must have been removed to get to the ABS and they forgot to tighten the 3 bolts. If you got the DC-DC converter out before, you should have no trouble replacing (if indeed it is the problem).

 

Thanks! I found that same link as well and got it downloaded. I finally got techstream up and am showing a current C1241 error which is about voltage received by the brake control power supply, the p0a08 code didn't show up at all. Looks like the brake control power supply or hybrid control system could be the issue for that. More digging to do!

 

Hi I was referred here from another thread.
So I just picked up the autel 2500 and it connects just fine but when I click on the service tab on the bottom and click on the ev battery section it just spins and then nothing happens.
I saw this link to the maxi app here but is it safe to download?
I have the maxi app from the Play store but I don't see any updates.
The dongle updated a few times when I first plugged in but that's about it.

Please advise I'm trying to get inf codes to fix a a p0aa6 error

Thank you

 

I don't have one of these, but maybe that isn't the tab you want. P0AA6 is a trouble code, just use the code scan feature. Pull up the freeze frame for the P0AA6 code and the INF code(s) should be in it.

 

Hmm I can check again. Interesting that this code would be found in freeze frame. Alright I'll check again but still weird that I can't use the EV battery function in the app

Can someone tell me if the link is safe to download install that was posted here for the Maxi app? What is the solution for the security patch that autel customer service stated?

Thanks again all have a wonderful weekend

 

Try running a full scan using the version of the app that you downloaded from Google play. If the full scan does not complete, then try a newer version of the app.

Did you look at the video of a full scan that is linked in post #40?

The trouble code P0AA6 creates a freeze frame with data items collected when the code is triggered. This is done for troubleshooting purposes. The INF code is one of the many data points that are collected and can be accessed by looking at the freeze frame data.

 

I understand that I think. It's just that is another function in the app that just spins (loading) and nothing happens. I can only do the "basic" scan and clear the code to start the car. The problem obviously seems to be the app.

Just to ask again to all, what was the solution to the security patch from autel?

I'm not brand specific I just did research from another thread here to find the inf code to find a scanner/ dongle which of course led me to buy the autel.

Thanks again

 

What happens when you try to do a full scan?

 

Instead of posting here, have you logged a support call with Autel?

That is how another PC member resolved his issue when he had similar problems.

 

Wow, a lot of relies since I saw first post by Dahvid yesterday afternoon. I'm sharper in the mornings, so waited to reply.

1. The updated app version that Autel gave me link to (v1.06) seems safe to me. I am not very cell phone savvy, and took me awhile to download it because of all of the pop up ads that appeared and looked like the download.
2. I scanned my 2004 Prius again this morning. Took a few tries, but finally got results of no DTCs (yeah!)
3. I tried clicking on the Service tab at bottom of screen, and then on EV Battery. It did just "spin" for a while, and then got a couple of different screens:






Not sure what the "Diagnostic data loading exception" means. I usually connect my cell phone to the web via Wi-Fi when inside the house, but perhaps the signal can't reach outside to the garage? I tried turning on Mobile data (roaming) and still got same results.

Like someone else posted, perhaps this Service Function is just not included because the Prius is not a 100% EV?

If you cannot perform a Full or Custom Scan, then I would definitely try deleting your current app version and downloading the version 1.06 direct from the link that Autel provided to me.

Sorry I can't be of any more help.

 

More info. The link in Post #40 to Autel actually is a hyperlink. If you click on it, this is a screen shot of what you should see:



Interesting that the most current build (8) is still identified as Version 1.05, published 9/11/2024. And in other versions, build 7, published 8/29/2024, is identified as Version 1.06. You may have to try build 7 and build 8 to see which one will let you perform a Full Scan. Autel did get back to me fairly promptly when I contacted them, but I think the reply came from China, so it might take until their Monday if you try to contact them for clarification or suggestions.

 

Along the bottom of the screen, you seem to be in the Service tab.

To investigate a trouble code and its freeze frame/INF codes, you probably want to be in the Diagnostics tab.

I'm not sure why stuff in your Service tab isn't working, but that could be a question for another day.

 

Nothing it just spins and never loads. It stays on that screen

 

I did send them an email a couple of days ago, no reply as of yet.

 

You need to install build 8 of the app. See post # 53.

 

Just did it. Will try it soon. The play store version is 1.62 but I downloaded the version 1.05 from #53.

I was also sketch about downloading from an unknown source but I went ahead anyway.

 

You also need to have the Toyota file loaded on your phone. See post # 38.

Edit: When I check the MaxiAP Diag app on Google play store, the version is 1.05, Updated on Mar 2 2024. I do not see version 1.62

 

Oh nice catch! I had to scan my vin to bind the dongle to the app. Then I had to scan it again for the "ev battery" option. I did not notice nor did it prompt me to download the toyota data.

Thanks again all