Which battery should I buy?

So why didn't AutoZone load test your 12 volt battery in the trunk AutoZone can't do anything with your high voltage battery but if your low voltage 12 volt battery cannot pass the load test then it reeks havoc on the rest of the car and all those lights start popping off so on a Prius one of the first things you do while you're at AutoZone thinking something is wrong because lights are on is you get them to load test the 12 volt battery it's real important. If you have a voltmeter you can pull the plastic tray up and check and see if you have 12 volts after it's been sitting for 6 hours or something If it dips below 12 volts even if it's 11 7 11 9 that's below 12 volts The system is a 12 volt system the battery should hold 12 volts so that 11.7 11.9 battery when you put a load test to it it will probably fail and that means the battery is no good for your Prius so the first thing you do is get the 12 volt straightened out while you have what you have right now if you don't want to buy a 12 volt because you're thinking well if it's something else I may be stuck with this $250 battery and then I find out I need a HV battery and a brake accumulator and that's $5,000 I don't want to put that in this car. You need to have the codes red by a very capable scanner like Toyota's tec stream . Some places have it dealers definitely have it some places now have very capable scanners that can read all the 15 18 20 computers in a Prius so if you don't want to get the 12 volt right it looks like it may be right enough to give you the correct code you need to make the choices you want to make If not you may have to replace the 12 volt battery to get the computer's booted up enough to give up the codes that could be a thing You could try charging said battery to get the codes but it always come back to the codes in Prius

 

You can not trust any of the test results until you are positively sure that the 12 V battery and its main connections are good.

And I can not read a post like yours that is all run together (not that you care).

 

I have been wanting to say the same thing!!

Refusing to use punctuation is about as rude as one can get!

 

Come on guys. There are at least two periods used and a few Capitol letters in this string of consciousness.
What more do you want?
An easy to read, normal English Languish syntax, like sentences and paragraphs?

 

how old is the 12v? you need to have that load tested for free at auto zone as tom mentioned. if it's good, put a voltmeter on the jump point under the hood and see if the voltage measures the same as the battery.
if it does, you either need a new ecu, or the connection to it is corroded

 

Since financial budgeting is not in the equation and getting car back to normal is, replace both batteries. You’ll be good as new!

 

Likely the 12V, can you jump start it?

If so, did all the warning lights went away?

12V could use a recharge, and then load tested it for condition;
Or just replace it if it's 5~6 years or older...



Posted via the PriusChat mobile app.

 

The one that looks like this:

 

You don't have the complete picture. While one of those codes COULD be a problem with the 12V battery, it could also be a fault with any of the wiring that brings power and ground to the brake control ecu. The 12V should be charged and tested.

The other thing is this Fixit place doesn't have a fully capable scantool. The report states "Innova"- some of their tools only claim to do the "common" ecu's: ECM, transmission, ABS, airbag,etc. They pulled a C1310 from the brake control ecu- that codes is "hey, the hybrid control system said it has a problem, you should go over there and see what's going on". However, I don't see any codes from hybrid control ecu.

You need a better scantool to get codes from all ecu's on your Gen2.

Posted via the PriusChat mobile app.

 

In keeping with some of the train of thought in this thread and particularly the point raised by Sam Spade, you cannot do a reliable diagnostic without a reliable 12 V power supply. Given that the OAT was reported by you to be -10ºF that will have a bearing on the ability of the 12 V battery to function well. Now that temperatures are higher albeit still cold, the highest priority is to charge and test your 12 V battery.

I will also reiterate the point that was made by Mr. Mann, the report you have is incomplete but before pursuing this ensure that the 12 V battery is charged and tested as good. If not good, replace. Then, go on and check other stuff. You might need to clear any codes after testing/replacing the 12 V battery or you could end up chasing codes that no longer exist. I will also note once you get to the point you are confident the 12 V supply is good and if you still have a C1241 code, do not overlook Mr.Mann's other point about a fault with any of the wiring harnesses that brings power and ground to the brake control ECU. This includes the connectors at each end.

PS: Go and find 2 threads in which you can post something useful so that you pass the moderation threshold. We can then see your post immediately after you post them.

 

My guess:
The first and only option they will give you is:
Replace the "main" ECU at a likely cost of $1000 or more.

My suggestion:
Before you agree to pay for that, ALL of the connections to ALL of the computer control boards should be unplugged, inspected and re-connected.

AND.....when the new battery was installed, was it fully charged FIRST ?
And was the other end of the two main battery cables checked and cleaned and tightened if needed ??

 

what is the code? which icu? it may still be corrosion, but a bad icu is a possibility