P0AA6 Code / 526 Information Code--need help!

I am having the same problem with my car and the (very nice) service guy at Toyota told me that they couldn't figure out what it was that was causing the problem, but didn't intimate that it was too serious, but if it is a 5K fix, then it must be. He just told me it was a short. Keep me updated if the lights come back on for you. I am getting P3009 and info code 526 too. I haven't had it towed (too cheap), I keep unhooking the battery. My dad is going to install one of those battery isolators so that I don't have to keep manually unhooking. Unfortunately I just bought the car from someone about 2 months ago so I don't know any history on the car.

 

This is exactly what my sheet says:
52204 USED SCAN TOOL TO INSPECT CODES HAS CODE P3009 INFO CODE 526 NO SUB CODES IN HV ECU CODE IS FOR HV SHORT WITH NO SUB CODES NO SYSTEM OR AREA IS FLAGGED CANCELLED CODES AND TEST DROVE 67 MILES AND DID NOT REDUPLICATE

 

After you pull the battery--the computer resets and the codes are gone--and the car goes back to normal (not that it ever seems like anything is wrong with it) with no lights. The problem is when I take out the key with the lights blown and the codes in the car and try to restart, then it won't start and I have to pull the battery. Is this what happened with yours--once you turn off the car, it won't restart? So I guess it's like a hard restart on your computer (the old paper clip in the reset button). Once I do that it doesn't show up again--My car has done it 3 times in the same 1 mile stretch of road, maybe just right conditions to get the light.

 

Hi Juliem,

I got same problem with you. My car was in dealer for 3 week. First they replaced new hybrid battery, then inverter. After they replaced installed new inverter I got another problem comes up. Just about 2 minutes you turn on AC, the problem sign appears on MFD. Once you turn off ignition, no ready sign. Now they complain the ac compressor. Since my car is over 150k, I'm totally out of warranty. It costs me about $4k and still can't fix the problem. How about your car got fixed at last?

 

the saga continues

http://priuschat.com/forums/gen-ii-...ights-triangle-vsc-transmission-problems.html

 

Thanks Patrick, which one of these is for info code 611? Just heard from Dealer here in FL that I need new transmission based on Electrical Short in the transmission. It was P0AA6-526, info code 611. Quoted $4,523. I have a 2007 with 79K miles. I can't afford this fix and was counting on great gas mileage to cut operating cost. Anything I can do on my own?

 

DTC P0AA6 means that the car has a high voltage ground fault. Info code 611 means that the fault is in the AC compressor or inverter.

If the fault is in the inverter, the 100K mile hybrid system warranty should cover the repair cost. If the fault is in the AC compressor you are on your own.

To narrow down the problem, the AC compressor should be disconnected, and then see whether the fault code comes back. If yes, the inverter is the problem.

If the info code had been 613 then the transaxle or inverter would be suspect. Similarly in that case, you would disconnect the transaxle cables from the inverter and see whether the fault returns or not. If the transaxle needs to be replaced I suggest you purchase a used unit from a salvage yard to cut your repair cost substantially.

In the meantime, if you want to defer the cost of a repair, you can disconnect the 12V battery negative cable where it attaches to the body for a few minutes, then reconnect. When you do that, the hybrid vehicle ECU will lose any stored DTC which will allow the car to start. You will need to do this each time you want to start the car.

 

OK, I have unplugged the compressor from the inverter. The car has had no other faults show up for several days. If I go ahead and have the compressor replaced should I have the wire bundle to the compressor tested to be sure?

 

Yes, but unless the car suffered front-end accident damage it is not likely the problem is with the high voltage wiring to the compressor. To confirm the compressor is the problem, use an ohmmeter to measure resistance between each of the three power terminals and ground. The resistance should be infinity if the compressor insulation is good.

If you should find the compressor is good, then do the same measurement on the inverter terminals feeding the compressor. However, before you do that, you must make the Prius IG-OFF then disconnect the orange traction safety interlock on the traction battery.

When reconnecting the safety interlock, remember to pivot the lever 90 degrees, then slide down to lock it in place.

If you should find both components are good, then run the AC compressor during normal driving until the fault code comes back; then repeat the above measurements.

Good troubleshooting work on your part, BTW.

 

Patrick, I have a new compressor install (local professional help). We used the Toyota oil and followed the procedures but the compressor will not start. Any ideas? Does the car need to be reset with the new compressor? hate thinking about pulling it back out.

 

Well, if the old compressor operated (although producing a fault code) then if the new compressor does not operate, there is something wrong with the installation wiring, or the amount of refrigerant in the system, or the new compressor is DOA.

 

Whenever you get weird codes or strange behavior, check the 12 v battery.

 

I don't know if this will apply to your specific problems but my 2009 Prius popped P0AA6 with info codes 526 and 613 this past week. Disconnecting and re-connecting the 12 volt battery will reset the P0AA6 and allow you to drive the vehicle until it pops the P0AA6 code and you turn off the car. Disconnecting the battery will again let you drive the car.

On mine, what I found was my inverter coolant had gotten low. I guess it had gotten low enough that the inverter temperature was affecting the detection of the voltage drop detected by the Prius internal diagnostics. I discovered this quite by accident after I had spent a lot of time going through TIS documents and the internet on probable causes for the voltage drop. I was preparing for a short trip and doing my normal checks (yes I was going and facing the constant battery disconnect/reconnect). Topping of various fluids and other standard maintenance items. I while the reserve tank indicated it was time to top off, I did not expect it to eliminate the P0AA6 problem.

 

I'd say it was just coincidence. The inverter coolant/inverter overheating cannot influence a high voltage isolation fault.

You need to come up with an alternate theory.

In most cases, the only way to clear a P0AA6 is to remove the path to ground.

In your specific case, the codes indicate that the HV ground isolation fault is in the transaxle area.