Master System Warning Light, Hybrid System Warning Light, dealer says 12V battery? Help!

I have heard of a weak 12V battery doing funky things like this, but still sounds a bit suspicious. I would let them replace it but make sure they pull all the codes (before they wipe them by disconnecting the battery) and document them in your file along with your description of the incident. You should still be under the 8 year / 100,000 mile warranty on the battery, so you want to be building up some documentation in case you have issues later. When you get it back I'd take it back out in the canyons and see if you can reproduce the problem. One of the symptoms of a failing HV battery can be big swings in the battery charge level in regular driving, but its not unusual for the battery to get down to two bars or as high as full bars on long/steep hills. BTW if you have the issue again, you may be able to clear the error by cycling the car on and off 3 times. The codes will still be stored for the dealer to retrieve, but you probably don't have to leave it overnight or tow it if you can get it to reset.

FWIW I had no issues getting the HV battery replaced under warranty in my salvage/rebuilt '05 when it failed around 7 yrs & 85k miles.

Good Luck,
Rob

 

welcome to priuschat! it's hard to know on a salvage, so many things can be an issue. sorry you bought it without checking in here first. the important thing is to have them pull the codes. you can have auto zone do this for free, and get a cheaper 12 volt. don't buy an optima tho. all the best!

 

Where was the car hit for the salvage title?

Make sure the car has had the Inverter coolant pump replaced under warranty as there is a TSB out for it. Or that pump may have failed.
Very common.
Put the car in READY and open the hood and take the cap off the while slim bottle bottle just to the left of the Inverter the square shiny cover. Look inside at the coolant level and you should see violent agitation which is the pump circulating the coolant.

The reason the car most likely threw the codes is on the way up the big hills it ran very low on Hybrid battery level and you being a new owner didn't realize thats the Prius Achilles heal. When the battery goes very low to purple and your going up a steep hill and you feel like your losing power the natural reaction is to keep flooring it instead of backing off. That usually ends in disaster as a very overheated Inverter coolant and Hybrid battery. usually the Inverter crowbars and the car will shut off.
If you have the codes pulled I bet they say Inverter overheat. You also heard the very loud battery cooling fan in the backseat come on too.
Make sure that fan inlet is never covered.

Steep hills are very hard on a used Prius with poor coolant maintenance and driven like a regular car with no attention to battery charge level.

The reason it was full green as you descended is you were on heavy regen all the way down....engine was racing....that's when you should use
the B mode on the gear selector.

 

Agree with the others. Pull codes, save them and document them. Then replace the 12 volt battery. FWIW, you can do that job yourself with a minimum of hand tools. It is not much more difficult than a regular car. On the Gen II Prius (your car), you do have to move a couple of things to access the battery, but again with just a few tools and some time, you can successfully remove and replace the battery. In my signature file below you will see several links. Study the link that talks about changing the 12 volt battery. Read post #8 for a detailed description of the tools needed and the steps you will perform to do the work.

Here's the battery I recommend. You can buy it directly from Toyota for $200.00 Don't pay them to install it. You can do it yourself.



I am disabled and still was able to change the battery in my own driveway in one hours time. FWIW, the Gen III (2010 through 2014) are easier to change out the battery as you do not have to move the vent duct work. NOTE: If you own a base model Prius (NO SKS SYSTEM), the battery you require is smaller than the one above. Toyota will also carry it. If you want to use the battery above, you can. You simply change the tray the battery sits in, and then the battery will fit properly. Toyota also carries the tray. What ever battery you end up getting, be sure it is a AGM type battery, minimum of 39 Amp/Hrs. that also has the reversed JIS battery posts. The correct battery post configuration will look like the following. With the battery turned length wise and the post's being closest to you, the positive post will be on the left, and the negative post will be on the right. Also these batteries are sealed. A vent tube attaches to the battery to vent any hydrogen gas out of the battery compartment. It is important to install the correct battery whereas you can vent the battery properly.

Concerning the traction battery. There are alternatives, so don't think your only choice is $3,000 from the dealer. If it comes down to that, post back again and other's will surely help you. You can also do a Google search on traction battery repair/replacement on the Prius. You will find links that will bring you here to Prius Chat and other sites online. That subject has been discussed many times over the years. More than one (actually quite a few) have successfully rebuilt/repaired their traction batteries (big battery) on there own with minimal parts and minimal tools. It does require a lot of time, and some labor to remove and replace said battery, but the work can be done on your own. You can also opt out for a battery from a recently wrecked Prius. You can usually locate them in junk yards and at insurance auction lots. Sometimes you can even buy a wrecked Prius at an auction and get all the parts you need for a reasonable price. Adding to that, there are many services scattered here and there that will actually come to you and exchange your battery with a rebuilt battery. Some are fly by night, other's have been in the biz for a while now. Even more, the pioneer of rebuilt traction batteries sold the technology to Dorman. Now you can order these batteries at most part houses, and then have your dealer install it for a fee. So, when you put it all together, a failing traction battery does not mean RIP Prius. It just means you need to do a little TLC. Sorry to hear about the salvage thing. Next time, maybe you can find something that is not salvage.

The other item to consider is what Ed is discussing above. You might have had a inverter overheating. Check for turbulence, flow in the inverter bottle when the Prius is in Ready mode. The inverter bottle is the small rectangular bottle that sits in the middle of the engine bay. It is narrow with the longest side parallel with the front wheels. Look for a level change from the back to the front also when in Ready mode. If the level of the fluid is even from the front to the back, then the pump is NOT working properly. That can be repaired. A failing inverter pump can cause issues that you mentioned. A failing inverter pump can also destroy your inverter. So take the time to confirm that the fluid is moving. If you see it is moving, you might consider having the fluid changed and the system bled. You can DIY if you follow the procedures to bleed all of the air out of the system. The dealer can do the work for you for a minimal fee. Also, find a different dealer. The one you are working with does NOT sound trustworthy to me.

The inverter bottle looks like the picture below.



Again, start with the 12 volt and then go from there.

Best of luck to you,
Ron (dorunron)

 

It may be a bit of a crap shoot. If the dealer wants to they can probably use this as a reason to deny the warranty claim. I had been using the same dealer regularly for regular maintenance and some other recall/tsb services (including the inverter water pump one mentioned above) done free of charge. They had at one point at least noted that they knew the car had been in an accident. But when it came time to replace the HV battery they didn't raise it as an issue and I certainly didn't call their attention to it.

I'm not sure where this statement is in the owners manual, but its also possible that it applies only to the "regular" manufacturers warranty and not the federally mandated emissions system warranty that covers the battery.

Rob