I have 35 different codes

'techinfo.toyota.com' might be corrosion

what does the 12v read at the jump point under the hood after the car has been off for a few hours, and then, what does it read after you turn on the headlights for 15 minutes ?

 

Why do you think you SHOULD be able to figure it out ?
I think you need a shop visit.

 

Have the two 12 volt batteries been new batteries that you have installed?

Clear all the codes with Techstream and see what comes back. Remember to note the sub codes associated with all primary codes. Then take inventory and see what is what.

 

12.9. Off
9.5. On

is so blown inverter.

 

Did you reverse polarity jump start it along the way and blow the car up?

 

Can you give a little more detail here, what was measured and in what circumstances?

 

Stop trying to start the car. It isn't running, rather it sounds like it's running but it's more likely just the weak and rapidly getting weaker HV battery trying to start the misfiring ICE. The 12v just boots up the car, the HV battery starts the ICE.

My guess: inverter or inverter pump died but car was still driven (or left on) eventually bringing down both the 12v and the HV systems as neither are now getting a charge. Also if original, the HV battery is probably toast.

GOOD LUCK!

 

12V battery reading = 9.00 OFF 9.50 ON

9 volts off and 9.5 volts on?

You clearly have a 12v system issue, possibly including the DC to DC converter inside the inverter. Resolve that first before you mess with anything else. That low of a 12v system can easily be the source of triggering many of your codes. Maybe voltage readings at the underhood jump point would be more appropriate. Another question is whether the 9x volts is due to a weak battery, bad connection, or a large load drawing it down. It would need to be a pretty significant load to draw the inverter down to 9.5 volts while in ready.

The HV battery has a weak module in Block 3, but the others look ok. The car must have been in ready condition recently, because the other blocks are all 16.x volts, which means 8v+ for each individual module. The only way you're going to have 8 volts per module is if the HV battery has recently been under a charge condition.

IF you have previously attempted to jump the 12v system, and applied reverse polarity, you have most likely burned open the main fusible link located on the passenger side of the underhood fuse box, along with a couple collateral fuses in the same box. When the fuse box is in this condition, I've seen the brake pump run continuously and put a severe drain on the 12v battery, depleting it fairly quickly. This can be stopped by removing the 2 abs relays. (or at least that's how I stopped it to allow further troubleshooting). The further troubleshooting revealed the owner did a reverse polarity jump.

Can you provide some details as to what has occurred with the car since the last time you actually drove it successfully? What happened that caused you to first need a new battery?

 

luis?

 

AKA Final nail in the coffin for the OEM HV batteries 12 years later. The timing of the pandemic and the EOL for gen 2's batteries has been nearly a perfect storm.

GOOD LUCK!

 

@LuisPrius08

Are you saying:
I let the car sit October-January

Is the answer to this question:
Can you provide some details as to what has occurred with the car since the last time you actually drove it successfully? What happened that caused you to first need a new battery?

if nothing else has been done with the car, like no jump starts, battery installed backwards, etc, then you likely just have a 12v installation problem.

 

you have help here