P3190 - Depleted HV Battery - Phantom Fuel?!

Battery Bonanza
Two months ago, 5 minutes from home, coming back from a 6hr road trip I got P0A80 'Replace Hybrid Battery' code. I checked my Dr. Prius App and saw that some of the cells seemed to be struggling, but it wasn't in horrible shape. However, I bought this Prius used from a guy who had recently replaced the HV battery with a Green Tec Auto 'Remanufactured Battery'. The battery has a 1-year warranty, and I was still in that time period. So I warrantied the battery. Got the new one delivered to my house and while I waited for it to arrive, I parked my Prius in the back yard and borrowed a friends car.

Eventually the HV battery was delivered, but it took me a few weeks to get around to actually removing the old one and installing the new one. By the time I was ready to do this, my 12v battery had died (I had left my OBDII scanner plugged into the car and it has tiny flashing lights that are on even when the car is off. My guess is that drained the 12v). I jumped it and it started up just fine, drove it around a bit to charge up the 12v battery, then parked and turned it off. But after turning it off, it wouldn't start again, totally dead. It would start off a jump, but the 12v wasn't holding a charge. I tested the 12v with a multimeter, decided it was time to replace it, and bought a new OEM 12v battery from the Toyota dealership.

While I was waiting to get the new 12v battery, I swapped the old HV battery for the new one. That all went smoothly. I got the new 12v battery and installed it. That is the work I've done so far...

The Phantom Fuel
When I jumped the car, turning it on for the first time in probably 1.5 months, the fuel gauge was down to 1 pip and flashing. I dismissed this as an electric mixup because the tank had been half full when I parked it. Plus I have a vague memory of another time when I disconnected the 12v battery and the fuel gauge reset showing 1 flashing bar but it updated after I drove it around for a little while. Could someone have siphoned out my gas while it sat for 1.5 months?! I live in a very rural valley where we do not lock our cars or houses and I often leave the windows of my farm truck entirely rolled down with the keys inside. I didn't even consider the possibility that someone had siphoned my gas.

So I ignored the flashing single pip, drove the car around for a little bit trying to charge up the 12v that wasn't holding a charge. While driving it around I get a P3193 'Fuel Run Out' code. That worried me, but I thought, there is no possible way I'm out of gas I had a half a tank, this is an electrical mix up to do with my dead 12v battery.

Fast forward a few days: I've replaced the HV battery and the 12v battery. I start up the car and it drives maybe 30 feet with extremely low power before stopping completely. It throws a P3190 code. I attempt to turn it off and on a few more times to get it out of the road, each time the HV battery turns the ICE for a few seconds, but the car never properly starts.

I begin to consider the impossible... someone siphoned my gas?!

I went into town, picked up 2 gallons, put them in the prius, same issues persist.

My Fail Mary
I love priuschat, what an incredible forum, I've learned so much. Mostly how totally f*cked I might be

I read the post Car Ran Out of Gas, now code P3190 and won't run, and understand the implications of running a HV battery low through running out of gas. My MFD doesn't work so I can't see the HV battery bars, but I have Dr Prius, and the SOC of my HV battery is at like 12.5% (I know, I'm f*cked).

I know its possible that my MAF is dirty and I didn't get my fuel siphoned. Cleaning my MAF sensor is my next step. And I will put in another few gallons of gas just to be sure.

But I figure the MAF sensor and the fuel are somewhat irrelevant until I can figure out a way to recharge my HV battery. Some people on here have mentioned Prolong Battery Chargers, other have mentioned taking it to the Toyota dealership and asking them to recharge it (but I've read mixed success with this, some dealerships refuse to do it or do not have the charger on site).

My Questions
1) What should I do? Please help me
2) Should I put the old HV battery back in, hope that it has some charge, and can start the car up enough for me to do fuel and MFA assessment?
3) Should I spend $450 on a Prolong Battery Charger? Can I use the charger on the depleted battery when it is not installed in the car?
4) Do HV batteries that are sitting outside of car lose significant amounts of their charge just sitting there? Do companies like Green Tec Auto keep them all plugged constantly? Did the new HV battery get significantly depleted in the weeks that I let it sit before installing?

Appreciate any thoughts or recommendations!

 

Thank you all! These are very helpful replies!

Any advice on SAFELY testing the voltage of the HV battery? Not finding super clear guides online and I don't want to die

 

Thank you! This is exactly what I was looking for. My current multimeter is rated to 500V, which would not be safe, is that correct?

 

Update from a couple month later!

I finally got around to buying a Prolong HV battery charger so that I could recharge the depleted traction battery. I also cleaned the MAF sensor and throttle body (throttle body was very dirty). And I put in an additional 3 gallons of gas

Unfortunately, the problem persists. I turn on the car (it now says it has a full tank of gas) its sounds like the ICE is running for about 15 seconds and then it stops. Shows me the red triangle of doom and throws fault code P3191. Clearly the HV battery is turning the ICE trying to get it started but then gives up.

What could it be? If its a problem with the fuel pump, what is the best way to test the different components of that system?

As always, any help is greatly appreciated!

 

#UPDATE#

I decided troubleshooting the problem was above my head and I took it to a local mechanic last week. They have gone through two diagnostic levels so far and just got back to me today saying that the car turns on when the fuel pump is powered at the pump, but the electric signal is getting lost somewhere between the fuse box and the fuel pump, which is why the push start isn't turning on the car. Their guess is that rodents have damaged the wiring that runs to the fuel pump and I'm about to pay ~$600 in labour for them to disassemble a bunch of the interior to trace the wiring and hopefully replace the damaged section.

I think this diagnosis makes sense given the entire situation, the Prius sat outside in a rural area not being driven for more than a month and its very possible that rodents got in.

I'm wondering if anyone has experience replacing the wiring that runs between the fuse box and the fuel pump? and how difficult it is? how many specialized tools you need? If $600 in labour seems way too high or pretty reasonable?

Also any advice on avoiding an issue like this is the future? I have already 'mouse proofed' my Prius by covering the AC vents with wire mesh, and taping dryer sheets all around the engine compartment. I didn't wire mesh over the rear vent, which is possible where they got in. Any other tips or tricks for keeping Prii safe from rodents?

As always, thank you all for your invaluable explanations and help