prius 2 alert lights troubleshooting

well done henry, thank you!

 

Thanks! I think I might have the same problem.

 

Hi I'm new to this site and don't know anyone. I want to ask a question but don't know where to start. I have a 2005 2nd Gen Prius. My dash lit up like a Christmas tree. Took it to the dealer and the code p0a80 came up. They said I needed a new hv battery. The car has 249,000+ miles on it. We decided not to get a new battery. My husband and I looked at some Youtube videos and now my hv battery is out of the car. My husband tested the modules and they all test between 7.97v and 8.12v. According to what we've seen and read this checks out fine. My question is, could something else be wrong or is the battery just old? Any extra info would be appreciated

 

welcome!
you have to put a load on the battery to find the defective modules.
this is a fairly complicated procedure, and requires some special tools and expertise. are you interested in doing the hard work to learn?

 

I'll have to check with my husband...he's doing the actual work....Ok check with him and he said we can at least try, so go for it. Thanks

 

you will need a mini vci w/tech stream software (google). and an old compatible windows laptop.
this can be hooked up to the obdII under the dashboard to read trouble codes, and also to read cell voltages as you drive the car.
when you have identified the cells that are outside normal parameters, you will need to find new ones on ebay, and then balance them with the other cells.
this requires weeks of discharging and charging individual modules using multiple dc hobby chargers.
for complete details, see the thread 'Gen II Prius Individual Battery Module Replacement' by member @ryousideways you will find it on the first page of the gen 2 prius technical discussion forum.

 

The truth is that there is a lot more to properly testing a battery than simply testing it's open circuit voltage. There can also be problems with cell's capacity, its internal series resistance, and also charge leakage to consider. The OP might have got lucky in finding his only faulty cell by a simple o/c volt test, but this is not always the case.

 

Thanks for the video Henry. But why why why (delilah) do people insist on doing the inverter coolant check with the engine running. The thing about the Prius is that you can have it in ready mode without the engine running. It's not like that is a difficult thing to do, and it makes testing for ripples (flow) in the coolant reservoir so much easier!

Look at your coolant jiggling around because of all the engine vibrations. Let the engine shut off and it's stiller than a mill pond in there if the pump is not working. So much easier to see.

 

The inverter coolant pump operates in "IG-ON" mode, too. That takes the running engine completely out of the picture.

 

Yep that's true. It's a no go in accessory mode, but Ignition-On is definitely fine for testing it.

I sometimes use Ig-On mode, but I usually prefer ready mode here because we have the "EV" button as standard equipment (Australian and UK models). So the engine startup is easily suppressed, and that way I don't have to worry about the ig-on drain on my 12V battery if it's getting a bit tired.

But even if you don't have EV, and even if you don't know the procedure to make "IG-ON", it's still trivial to test it with the engine off. About a minute or less with all cabin heat turned off and just about any Prius is going to cut the engine. I just don't understand people trying to do that test, where you're carefully looking for ripples, with the darn engine running and jiggling everything about.

 

Thank you all for your input. My husband decided to put everything back together. We stopped at a Toyota dealer just to price out a new car and see whats available. Well, we ended up buying 2017 Prius Three. They gave us as much as it would have cost for a reconditioned battery for my old 2005 Prius. I love it! Its Sea Glass Pearl with black and beige interior!

 

congrats! another headache out of the way. all the best.