Red Triangle, Car Won't Start

I have a 2008 Prius Touring with 101,500 miles I bought a couple months ago. My problem started two weeks ago. I get the red triangle, yellow "!", and VSC lights while driving anywhere between 0.1 and 25 miles. When I turn off the car, it won't go into Ready mode unless I disconnect the 12V battery for 30 seconds and reconnect. Then the lights go away and the same things happens as I said before.

I checked my 12V battery and it's fine. It reads around 12.76 V when the car is off and around 13.8 V when running. I even cleaned the battery and its connections.

I recently noticed the inverter coolant pump had failed so I replaced that and coolant flows normally now. I thought this would solve the problem but 7 miles later and the lights are back on. I have no idea what the problem could be.

 

I got the codes read at a shop and they came up with P0AA6-526. They said they are unable to isolate which specific component is causing the issue without pulling the code multiple times and hopefully getting a detailed code for which part is failing.

The other method of diagnosis they said involved disconnecting each component of the hybrid system and using specialized equipment in order to isolate which component has the voltage leak which they said could cost hundreds of dollars for just the diagnosis.

Any suggestions?

 

Hi Travis,

I have the mini VCI cable with TechStream but it won't let me use it without some registration key. Then it directs me to the Toyota site and tries to get me to buy a key through some sort of subscription.

 

So I had the specialist shop diagnose the car this morning and here is what they came up with. My traction battery is corroded. I'm thinking there may be a bad seal somewhere along the car that has been letting water in and causing this. We have been having lots of rain recently since it's monsoon season in Arizona so I had always thought water could be the issue.

Here is what they say:
"Pulled codes and found 1--P0AA6 HYBRID BATTERY VOLTAGE SYSTEM ISOLATION FAULT with info codes 2-526 and 3-612. Inspected HV battery and found it's filled with corrosion, needs HV battery. Checked 12V battery and it's marginal dropped to 8V and 250 CCA."

Also, I thought my 12V battery was good because I had it checked at multiple stores and all had good readings and my multimeter reads ~12.7V when the car is off and ~13.8V when the car is on. If that needs to be replaced as well, I can do that myself as well as replace the engine coolant. I'm just very hesitant to go near the hybrid system.

They want to charge me $3,000 for a replacement traction battery. I had set aside around $3,200 for whatever the car needed so this is at the top of my budget. Any thoughts? Thanks, everyone.