Won't Turn Off -- Master Warning Light on (Red Triangle)

If fiddling with the auto window a few seconds and resetting the radio presets along with losing the trip meter numbers are a big deal to you then set up a second power source to save settings.

I had no problem without trying to save setting when I changed ours.

I do suggest that if you connect a second power source that you insulate the battery cables after you remove them to eliminate any chance of a short since those cables will be energized.

Sorry to hear you are having battery problems. Changing one in the winter is no fun at all. Had to do ours last winter and it was not near as cold here as it is there now.

 

Take a look at the attached file. Found this here on Prius Chat.

I also detailed how I did ours here on PC. Link in my signature file below...

 

The only thing I would add is to make sure the bolts go back in the same place. Especially the brake back up power supply. (Black Box by battery). There is a post here on PC that talks about someone shorting one of those out when they put the bolts in wrong. I have a habit of laying things out when disassembling something and keeping things in strict order. Not everyone does these little tricks. Some folks just toss bolts screws, etc in a dish and then try to figure it out afterwards by what ever fits.

Study the PDF file I posted also. Has more detail. The hard part is that top screw on the vent duct. Use tape on head of screw or some grease to stab the screw in the hole. A drop light helps a lot, it is real hard to see. Don't drop that screw if you can help it, otherwise you have to go fishing with a pickup tool.

Good luck to you.

 

Do you have a charger you can use on the existing battery until you get a new one? I bought mine from streetsideauto.com for $147 shipped but I did have to wait a few days.

 

OP does have a battery charger as illustrated by post #2.

 

great job so far, hope it's not too cold there!

 

1. It would be easier to remove the negative cable where it bolts to the body. Check the tightness of the negative cable both at the battery itself as well as the body. It is helpful to remove the brake power supply bolts (not necessary to remove the wiring harness connectors) so that the brake power supply can be moved to the side for easier access to the 12V battery.

3. After the positive clamp nut is loosened, it might help to rotate the clamp back and forth while exerting upwards force.

4. The plastic vent elbow inserts into the new battery.

 

It will be easier for you to attach the negative cable to the battery before you put the battery back in. Like Patrick said, remove the bolt that is on the other end of the cable where it hooks to the car frame. That is in the write up I did, but I guess you missed it. It all runs together since I did not number all of the steps.

For future reference when working with battery terminals, it is easier if you first loosen the nut a couple of turns, and then take a flat blade screw driver and spread the terminal so the terminal end will lift off of the post easily. To spread it, put the flat blade in between the gap where the bolt goes through, and rotate the screw driver. That will cause the terminal end to spread and loosen it's grip on the post. It only needs to be spread a little bit, so don't use a lot of force. The post's and terminal ends can be broken as they are fragile.

The lithium grease is exactly what I used. Put enough grease on the bolt where the bolt will stay in a socket and extension when the tool is level. Then use that to stab the screw back into the hole. Start it by hand, and only snug it up. The torque is very low. If you reap on it, you will strip out the plastic that the screw fits into. Actual torque for that screw is 35 inch pounds which is not a lot of force. I just snugged mine by hand using one finger on the ratchet.

Yeah, the back nut on the hold down bracket is hard to get too. If I recall, I used the wrench because I did not have a deep well socket.

Going back in will be easier since you are now familiar with it.

Patrick explained the vent tube, I have nothing to add there.

If you haven't looked at the PDF file I posted, you might want to do that. Very helpful information in there. Refer to post #22 above.

 

Hard to say yay or nay on the cardboard. Make sure you remove it before you start back with the install. I would have simply closed the hatch and then reopened with the handle inside. But what you did should be okay, I would think.

When you go to power up, you may have push the power button a couple of times to get the Prius to boot up. Don't be surprised about that.

A couple of posters had problems, claimed they left headlights on and could not reboot Prius. Never did hear the end of it. It did take two pushes of the power button on my end to get the Prius back up and running. As I recall, I never put the key fob in the slot. It was about a year ago when I did ours. Lots of pain meds since then.

Spreading the terminal ends can be tricky at times, especially if you haven't done it before. Some recommend twisting the terminal which sometimes helps also. The things are made out of lead, and can deform and break easily so care must be used when working with them. The point is you were able to do the job, and that is what is most important.

Did you read the pdf file I posted? Post #22 above.

 

No don't bother with losing the settings. There just radio presets. Its freezing up there so you'll be max'ed just changing the battery. Setting the radio presets are easy. Just some button pushes. Hit scan. Hit the the number setting.
All done in a warmed up car.


Are you going to change this battery yourself or is there a big team of rather large mice to help?
We can walk you through it or the mice....

 

Very good thinking. Yes, the hatch lock is electric, so you did exactly the right thing.

Alternatively, to open the hatch, you would have had to crawl back into the hatch area by folding down a rear seat back, removing the folding hatch floor, then finding the mechanical lock release located behind the rectangular opening in the black plastic tray over the spare tire.

If you need more fun with your Prius after installing the new 12V battery, you may wish to find the mechanical hatch lock release for future reference.

 

You could also hook up a battery charger to the jump point under the hood (even though the battery in the back has been removed). This will power up the system long enough to make the electric unlocking mechanism work. Once the hatch is open, remove the charger.

 

For safety reasons, some battery chargers will not produce voltage unless the charger senses a reasonable amount of voltage (from the battery) already present.

 

Very nice work, congratulations on your project success!

The reason that you see the sparking is because the brake power supply and various ECUs which are continuously powered on will draw substantial current upon power up, charging up various electrolytic capacitors. If your cabin lights are normally turned on, this will add to the current load. So this behavior is normal. After the ECUs are powered up, they will drop back down to a quiescent mode and the current draw will decline to a nominal value, around 0.02A when the Prius is IG-OFF and the doors/hatch are closed and locked.

You may find that the fuel gauge needs to reset upon first making the Prius READY. The engine idle characteristics may seem a bit abnormal initially, as the engine ECU will need to relearn whatever adjustments it had made over time. And the MFD mpg gauge also needs some learning to be restored to its normal behavior.

 

As said above by Patrick, you did the job well and I am glad that I was able to help in any way I could.

In case you forgot, here is how to do the backup beeps. Also works for the seatbelt, but different technique.


1. Power on the car (IG-ON or READY) and using the Trip/ODO button, make sure ODO is displayed (not Trip A or Trip B).
2. Power off the car.
3. Now power on the car to READY (brake on).
4. Within 6 seconds of powering on, press and hold the Trip/ODO button for 10 seconds or more (there is no indication... just count)
5. WHILE STILL HOLDING ODO *after* the 10 seconds, shift the "gear" selector to R, then press the P button. Now release the Trip/ODO button.
6. If the last step was successful, "b on" or "b off" should be displayed in the location where the Odometer is normally displayed (front dash area). "b on" is beep on (default), and "b off" is beep off.
7. Press Trip/ODO to toggle the mode.
8. Power the car off to exit the toggle mode.
9. Good to go.



And to disable each of the front seatbelt warning beeps, follow these instructions:

1. Be sure someone is sitting in the seat which seatbelt beep you wish to disable.
2. Without your foot on the brake, turn on your Prius and make sure you are in ODO mode (not Trip A or B). Power off the Prius
3. With your foot on the brake, turn on the Prius. As soon as the ‘Ready’ light is lit, press and hold the ODO button for at least 10 seconds.
4. Keeping the ODO button pressed, insert the seatbelt that you wish to disable the beep for. At this point, ‘b- on’ should appear on your dashboard display.
5. You can now let go of the ODO button, and each press of the ODO button toggles between ‘b- on’ and ‘b-off’. To disable the reverse beep, simply set it to ‘b-off’, the power off the Prius.

Best of luck to you and congrats on a job well done.

 

Kris,

Do me a favor please.

Run the test with the MFD and post all three figures after the new battery sits overnight. If you just finished putting in the battery that would be Ok too as long as the car has not been driven for at least eight hours.

I want to compare your new readings to what I saw when I swapped ours out last year.

Thanks!

Ron (dorunron)