I had a dead 12V battery replaced and the car will get into Ready mode but will trigger the Red Triangle and yellow (!) within a few minutes of sitting in Ready or driving. Dr Prius scan showed a P0AA6. Car will drive but once it is turned off I need to clear the battery code (via Dr Prius) or disconnect the 12V battery Took the Prius to the shop for detailed codes. The shop used a SnapOn scanner which showed the P0AA6 in addition to C1259, C1300, C1310. I asked if there were subcodes under P0AA6 but he either didn't know how to access them or the subcodes were not coming up. I removed the HV battery to inspect and didn't see any obvious corrosion. I replaced the HV battery was replaced 4 years ago with the cylindrical modules from NewPriusBatttery. There was a connector near the HV fan that looked a corroded so I cut and soldered two of the 4 wires. Not sure what these wires do. I did a search and ChapmanF in post #4 2010 prius c1259 c1310 | PriusChat stated: "It's pretty common knowledge here (but still needs the word spread to the new folks) that C1259 and C1310 are simply codes that the skid control ECU sets when it has been told there are trouble codes in the power management control ECU. So literally all those two codes mean is "never mind us, go find out what the trouble codes in the power management control ECU are."" I'm close to setting this Prius ablaze. Any help would be appreciated. Thank you!!!
The subcode for the P0AA6 would be of great help, otherwise we're guessing. The vast majority of the time, it's the HV battery, but not always. Could be the main cables, the inverter, the AC compressor, the transaxle...... Did you get a chance to look at the HV battery ecu socket where the voltage sensing harness plugs in? A copy of Techstream would do you good. There's a parameter in the HV Battery section called "Shortwave Highest Value" whicj measures the insulation value of the HV system. 5v is perfect, and any degradation will cause that number to drop. Somewhere around 3.2? will trigger the P0AA6 code. You can look at it before and after making the car ready to see how the value changes when the main relays shut. Techstream is also the best option for looking at codes and subcodes.
The P0AA6 code will normally have one INF code, 526, when it first appears, and that code just means "hold on, I haven't figured out the specific area yet, don't clear me and I'll figure it out after another power cycle." Later, it will normally have the 526 plus another code from 611, 612, 613, or 614, which will direct you specifically to one of these areas: However, if you never get the more-specific code, or you don't have a scan tool to see the INF codes, you can still just start at the very top of the P0AA6 troubleshooting steps in the repair manual and track down the fault yourself by a longer process of elimination. It's more tedious, but not magic. Toyota Service Information and Where To Find It | PriusChat
Just in case someone needs such : https://attachments.priuschat.com/attachment-files/2018/04/145252_2006_Prius_RM_-_P0AA6.pdf
Techstream is one scantool option. Another is to read this thread. There are a couple app + device choices that turn your smartphone into a capable scantool that can pull INF codes. https://priuschat.com/index.php?posts/3290690 Posted via the PriusChat mobile app.
What did you find out in regards to your situation? Today I was presented with a, girlfriend lined up to read codes, 2007 with P0AA6, C1283 and C1310 codes. The owner mentioned he could not shut off the vehicle or he would have to disconnect the 12V battery and wait 20 minutes or the Prius wouldn't go into READY mode. Read codes before we powered down and found the subcode 526 for the P0AA6 and mentioned the possibilities per reading regarding. Girlfriend insisted we start with the HV battery and sounded like a good idea since they had a spare to swap in too. While they cleaned the bus bars, terminals and ring connectors I probed around to see what was corresponding with the Service Manual troubleshooting steps. Got to the modules terminals in relation with the module case and found a module didn't have a similar resistance value. Decided to test for voltage and found 7.02-6.99V (error of DMM guessing) on one module negative terminal probed with the common and the V terminal probe to the case. The module is the one on the left arrow battery plug. Block 10 module 20. Bad Video Demonstrating Situation With I Don't Know Why I Said That Audio - YouTube Guessing the module is leaking and shorting out from the cell somewhere closest to the positive terminal on the other side being that module measured 7.94V. No HV battery ECU codes. HV pack charges and discharges with no observed issues on the MFD prior or using Autel MAXI AP200 and module voltage differences tested live were around 0.1V max. Being the pack was charged with all modules ~7.9V, I noted might be better to swap in the other HV pack and see how the vehicle performs while in the mean time letting the P0AA6 pack self discharge as well as potentially discharge with an incandescent lamp to shrink the pack length down as might be swollen due to being more charged. Reassembled and he was back on his way with future plans to I guess replace that module which I guess is leaking somehow and shorting to the case. We didn't visually observe anything out of the ordinary, though the typical bus bar and terminal nut corrosion was present. Guessing that module 20 is cracked or something with an electrolyte trace to the case on the bottom or side not visible until removed? Definitely a first for me. Also, maybe worth noting is that after clearing all the codes with the Autel MAXI AP200, the car would not go into READY mode. Had to disconnect the 12V battery and wait 20 minutes. Then was able to go into READY mode and he was off.
