Prius Doesnt start. Dashboard lights up

Team
I got a non working prius from someone who maintained it very well but it stopped working and they thought it was the HV battery. I got an alternatve HV battery and replaced 4 modules which had a 5V and put it back in with a new voltage of 15.6
The initial battery error is gone. Now I face the following problem
1) When i start the engine seems to run for 5-10 seconds and shuts off
2) I get the "Triangle of death"
3) The fuel gauges reads flashes empty when i start in "Non REady" mode.
4) In ready mode the fuel shows full
5) Tried to fill fuel and it over flowed. #4 is correct.
6) 12V battery is new but drained possibly becasue of SKS and the parking lot of close to home where the key is. I have diabled SKS (with Key button flip by Driver's knees)

Next Steps
1) I have added a new battery and kept it over night to see if battery drain will be elimated. Will report
2) I may have to check the fuel pump relay and fuse. Any help or debug around this?
3) Pull the fuel line from engine and start the pump using 12v. Any suggestions?

Thanks a bunch for your help on what else i need to do.

 

Apologies DTC code is p0a0f. I also see a Fuel empty code (I think p3193) but i didnt take a note of it because it may not be relevant

2007 Prius with SKS and 85k miles
Old owner claims it stopped working just so "suddenly"

 

Thanks.
1) Do either of you suspect the engine is not given the oppurtunity to start since the ECM thinks the fuel is low?
2) I have to be care full to keep the HV battery at charge. Right? Any alternatives as i debug to not drain the HV. I am looking at the following low current charger to charge the batteries at 220v dc. Will use 210v cut off switch to ensure i dont over charge. CAnt attach a link so have attached a picture from amazon


Any thoughts?

 

Thanks to all of you for being patient with me and responding

Yes will check MAF, Fuel pump Sparkplug .
1) Exaust is clean. Not blocked. I didnt even think about this until Mr_Guy_Mann pointed out
2) Checked the fuses and all are well. Havent checked the relays.
3) Battery Drain: I checked the battery and it was fine today. I also have a Renogy battery monitor and I noticed that current as soon as I locked the doors varied between .5 to 1.3 A (5W-14W). After about 15 min it when to 0A/0W. Battery may be ok. The battery monitor can detect only 2 two digit decimal But I am inclined towards conclusion the battery isn’t draining. Do you agree?

I have a Autel Maxsys pro. Is it possible to do some diagnostic work on that? I have seen be able to turn on components in a Mercedes Sprinter 201x models. Can something be done on a Prius GEn II?