Dead Aux Battery - 05 - need troubleshooting advice

1. Hook up your 12V battery to a battery charger so that it can be recharged. Expect this process to take at least 8 hours. If the battery doesn't hold a charge then you will know that it needs to be replaced.

2. You need a digital multimeter so that you can measure current draw when the car is IG-OFF. If you find that the current draw is more than 0.02 A or so, then you'll need to look for the cause by pulling fuses that provide power to likely culprits and seeing whether the current draw decreases markedly.

 

Well, you will need an AC outlet for the battery charger. If that is not available at your parking garage then you will need to remove the 12V battery from the car, and carry it to a place where you can connect the battery charger.

Once you have a known good battery, install it in the car. Turn off the two ceiling lights and the hatch light.

Connect the DMM in series with the 12V battery negative terminal cable where it connects to the body. Do not turn the car IG-ON while the DMM is in series. Most DMM have a fuse that will blow if current flow exceeds 10A. Place the DMM where you can see it when the hatch is closed.

Close the hatch and all doors. Keep the Smart fob 15 ft or more away from the car. Watch the current draw. After a few moments it should drop down to a stable value. See what that value is.

 

KC, by any chance are you downtown Brooklyn? If you are I can meet you and get you a jump start via my auto insurance roadside insurance.

 

I'd measure the battery -first-. Directly. It may just be a poor connection to the car body at the -ve cable. Your first experience is what makes me think this. When you first tried to start it nothing happened. If the battery was truly dead, holding the start button down shouldn't make any difference. If there is poor contact in either battery terminal, slight loading may burn off some of the oxide and then it could provide enough to actually start the car (it doesn't take much, BTW). Also check the +ve terminal. Either could be either loose or corroded. Especially if you didn't clean them before connecting the battery when you first got it. The oxide is hard to see on lead terminals.

 

Before charging it or removing it, I'd check the voltage directly across it. As I said, it may just be a connection issue. You can open the hatch from the outside if you connect a 12V source under the hood (as if you are going to boost it). If you do it this way you will -know- if the battery is actually dead. Then you can go from there. Or if you don't want to go through the hassle of getting 12V to connect to the boost terminal, crawl over the back seat, lift the floor cover and release the hood at the release lever (center of the hatch, just under the hatch door).

You can purchase portable boosters. They contain a gel cell battery and charger (and often a light, air pump, etc). They don't cost a lot. You should be able to find one for $50 or less.

 

Disconnect the negative battery terminal. Wait for 5 minutes to pass. While waiting, make sure that the positive battery terminal is tight.

After the 5 min period, reconnect the negative battery terminal, making sure that both cable ends are secure.

Then your car should be back to normal. You'll have the blinking fuel gauge for a few moments until the combination meter ECU figures out how much fuel is present. You'll have to reset the driver's window auto up/down and the radio presets. The trip odometers will be back to 0.

 

It sounds like you just had a bad connection. I've experienced this myself when I hand tightening the ground bolt when I needed to wrench it securely on a test drive after a fix requiring removing the voltage.

Scan Gauge codes: P0000 (those are zeros), and U0(zero)111
Prius computer gave this on checking the LAN: EMV Code 01-DC, Sub Code 1C6-CB-1
It also didn't seem to allow me to clear it.

Codes that don't clear after a battery disconnect should eventually clear with several on/off cycles, at least they do with me. I always have many error codes every startup after disconnecting the +12. I may not be something correctly though I did find cycling to IG-ON and off and then to READY mode helps..

 

I have dead 12 volt battery, what type battery can I put back in,

 

Either one that you can buy from the dealer, or an Optima available on line from eLearnaid. I have the Optima. Not sure about the spelling of eLearnaid, but easy to find on google.

 

Do note that if the terminals were dirty/oxydized the battery charge level has probably dropped way down as it won't charge properly. So you should make sure the car is in "Ready" for several hours before shutting it off after you clean the terminals. It will take longer than that to fully charge the battery, but that should be enough to keep it going until you do get it fully charged (takes about 8 hours to fully charge a dead battery using the Prius in "Ready").

I use a battery terminal cleaner, which you can purchase at most automotive stores for under $10. They have a round wire brush at one end (usually with a cover over it) and a post brush at the other. Use the post brush on the battery terminals to make them shiny, then use the round brush inside the cable ends to make them shiny on the inside. You push the cleaner over the posts and turn it several times to clean the post. Ditto for the cable ends. Very important even for new batteries. They come "pre-oxidized".

 

You have two choices, a battery from the dealer or an Optima with cable adapters from elearnaid.com. They are about the same price.

And I should learn to read all posts before answering, but saying it twice underlines it.