Hello guys. I have a 2010 Prius with code P0AA6-526 Isolation fault. P0AA6 526 I replaced the engine and flushed the radiator and heater core top and bottom hoses and looks like something is shorting out. I’ve attempted to dry everything out and nothing has helped. Car runs but after about a minute of running check hybrid system pops up. I have techstream and have the following readings. I’m not too familiar with techstream can someone maybe point me where to start isolating and checking for ground. Thank you
526 is just the car saying "I noticed an isolation fault, but haven't narrowed it down yet." Try to READY the car up one more time (without clearing anything), and you should get the same codes, but also with a 611, 612, 613, or 614 INF code. That will help you narrow down where to search for the problem. Be aware that image is copy/pasted from a Gen 2 thread. Gen 3 does the air conditioning differently: the gen 3 A/C inverter is moved to inside the compressor. That means gen 3's 614 area also includes the orange cables to the compressor, and the 611 area is just inside the compressor itself.
—— I’ve drive the car for about 30 minutes and still only getting P0AA6 526 I’m not getting any sub codes unless I’m not looking in the right location. Any suggestions? Greatly appreciated. thank you
You're sure you haven't cleared the P0AA6-526 code? Driving the car might mean you had to. The car sets 526 when it first notices a P0AA6 issue. The next time it readies up (or fails to ready up), it sees the 526 and says "oh, right, I was going to try to pin that down further", and comes up with a 611–614. Sometimes people keep resetting the code and so never get any further than the 526. The first-generation Prius didn't have those 611–614 codes, and so people driving gen 1 would have to go through a little careful startup sequence (clear the code, does it come back in IG-ON? Not until READY on in Neutral? Not before shifting out of N?) to get roughly the same information. You can still do that sort of thing in a later generation—it's essentially what the car does for you (faster) when it sees on startup that it logged a 526 before. Because of the electric A/C in later generations, you have to add a last question "not before I use A/C?".
Prius P0AA6 No Start — Most common cause — Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice | Car Repair Tips and How-To Advice Diagnosing a P0AA6 Code — PriusKings Hybrid Battery Specialists
i have not resetted the code. Car starts up and charges the hybrid battery in the beginning. After driving the car it doesn’t charge it until the battery is low at about 2 bars. Or if I shut off the car and restart it it will recharge again. Then I go and check for codes and only P0AA6 526 code pops up. Nothing else. Any other suggestions.
Tech Tips *1: INF code 526 is stored together with P0AA6. *2: The insulation malfunction detection circuit in the battery voltage sensor monitors the insulation resistance between the high voltage circuits and body. If the insulation resistance decreases, the power management control ECU stores DTC P0AA6-526 and illuminates the MIL first. *3: If the following operations are performed within the same trip after DTC P0AA6-526 is stored, just one of the related DTCs (P0AA6-611, 612, 613 or 614) will be stored. Apply the parking brake firmly. Wait for 1 minute or more with the vehicle stopped, the brake pedal firmly depressed, the power switch on (READY), drive (D) selected and the air conditioning system on (Lo/COOL MAX, blower speed HI), then turn the power switch off and wait for 1 minute or more. If DTC P0AA6 is stored, the vehicle cannot start. When measuring insulation resistance using a megohmmeter, measure the resistance while jiggling the high voltage wire harness. What version of Techstream are you using? Can you make a screenshot showing all the systems and errors for these systems? P0aa6-and-526 by MAX2 posted Mar 31, 2025 at 4:45 PM
