Going to buy a 2005 with a dead hybrid battery

Maybe you can sell this car for $2000 after you fix the battery. Then buy another prius you can depend on

 

Sounds like it's not just the battery. If the interior and such is in good condition and you have the time and patience, parting it out would be profitable. Prius parts aint cheap.

 

I concur with the 12V battery replacement. I had seemingly unrelated codes come up when my 12V was weak. If you go after codes you will be chasing your tail for a while. I had a repetitive P0446, which is evap system test failure. After I put a new 12V battery in over a month ago, no more code. Also Parking System warnings went away after a fresh 12V battery. Just going after codes is not a great way to tackle repairs. I would first get the thing running more or less properly, do the obvious things like engine and transaxle oil change, filters, 12V battery, etc. Then see what else is going on. This car does not sound like a keeper to me. Too many things to do. But that's me. Your situation is your own.

Best of luck with it.

P.S. After deciding to buy my very first Prius (also first hybrid and first Toyota) I looked for candidates for several months. Then The One came along. A single owner '07 with 175K miles and not a thing wrong with it. Well taken care of and loved. I paid $3,400 for it. I invested into Prolong system (to the tune of $700) and performed one reconditioning so far. The SOC on the battery is now always in blue and often in green. I love the car, but it was in an absolutely beautiful shape when I bought it. I looked at one '04 with bad battery for $1,500. Drove for almost 2 hours to see it. It also had a dent in the rear quarter (they are famous for that), bad shocks on the front, god only knows what else. It drove, but had a triangle. I left very quickly. Just do not like that much trouble. It had a fairly clean beige interior, too.

 

Disconnect the 12v battery and all the codes will reset. See what codes come back

P0a80 is not related to anything other than hv battery

 

Did you have the 12v disconnected when you were working on the HV battery or did you leave it connected so you'd be able to operate the doors and hatch? If you left it connected, I can understand why. Its a pain not being able to open the hatch from the outside when you need to. If so, I definitely agree with JC9. If you're not able to reset the codes via the OBD port, disconnect the 12v negative cable for a few minutes.

 

Bunce, what instrument are you using for reading codes?

 

I don't have that one on my apps. I should probably download it. Does it offer additional data for subcodes of the P0A80? (hmm. does p0a80 have subcodes..my brain is fried today..) no, no info codes for p0a80. Does it offer freeze frame data?

 

If you're able to get graphs of the block voltages while driving, that would be a great help. We'd be able to see how each block reacts to a decent current load.

Another simple app is Hybrid Assistant and Hybrid Reporter, The HA app has an option at the bottom to do a battery check. If you select that button, and then drive a bit, it will log all the HV battery info, which will save itself when you exit the app. Then run hybrid reporter. It will show you the saved file, select it and then the app will provide all the graphs. You'll just need to scroll down to the battery health graphs where it will show all 14 blocks voltage graphs from the entire drive.

 

Bunce,

Here's a screen capture of a graph provided by HR. This was done just by warming up the car so the engine would stay off, start the HA app, then run the AC on full blast, then pressing the battery test. I ran it to discharge the battery from about 80% down to 45%, then stopped it and saved it. Open HR app and select the file and it will graph it. You can clearly see each module's voltage curve. Stronger blocks hold their voltage better. Weaker blocks will be lower on the graph since they lose their voltage faster.

If you do the test while driving, the graph will have a lot of ups and downs, as the battery will discharge and charge, but you'll still be able to see the strength of each module relative to each other

You can also do a load test as recommended on the HA app website, which uses a method of placing the car in 'reverse', holding down the brake and giving it throttle to load the battery while the HA app records data. That works also.

Of course, a P0A80 can also be due to the HV battery ecu, not just blocks/modules, but most frequently, it is the block voltages

 

Your 12v battery is probably low. Check to make sure it's over 12v

 

What code is it showing now?

 

If you disconnect the 12v, you should have to press the 'power/start' button twice. After reconnecting the 12v, put foot on brake, press the power button, wait a few seconds (dash will still be lit up) then press power button again. All alarms should clear and car should be ready to use.

If you do that procedure, what happens?