Troubleshooting Prius old style way with only multimeter and spanners

If you have loose HV battery connections with damaged fasteners- tow your car to someone who is capable of doing proper repairs.

Harsh but this is an area you need to be careful and meticulous about torquing fasteners to spec.

Damaged studs on battery will often need to have those modules replaced.

"Randomly" replacing modules will almost certainly result in a P0A80 code because the "new" ones will have different capacities and state of charge from the existing ones.

The P3030 is either because of the loose connections, or corrosion damage at the ecu connection. Usually have to replace the voltage sense wiring harness and the battery ecu.

One of the battery temperature sensors was likely broken during previous work. (P0A9C)

P0171 is commonly caused by dirty sensing elements in the MAF sensor.


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Think of it like this.....Each wheel on your car has 5 lug nuts. If the driver side front wheel had 5 stripped lug nuts that you couldn't tighten, but the other three wheels were ok, would you drive the car?

 

Do a battery load test on each individual cell; next time it's apart. I have a feeling most of your batteries won't pass - they're pushing 18 years old. How many 18 year old batteries have you run into that are still functioning within OEM specifications?

 

Yeah your just replacing old dead cells with old cells that happen to have 7 volts on it. So what...You have no idea of its current capability's.
Its ability to provide current under load.

The minute you put a load on it it dies. Any cell you use to replace a dead cell must be load tested to test its viability.... Like Bio said.

And btw, there all the same vintage year battery cells very very old that just happen to have 7 something volts on them. Plus the pack needs to be balanced.

There's is literally hundreds of battery rebuild threads on this forum that go into deep rebuild of this battery including load testing modules.

Start reading:

https://priuschat.com/search/443845121/?page=2&q=hybrid+battery+rebuild&t=post&o=relevance

 

The HV battery in my 2007 touring has manufacture dates of 2003 on the modules and it's a beast......