2005 Prius HV battery troubles

Hello everyone. I am new to Priuschat.com and really could use some help.

I have a 2005 Toyota Prius that has recently had problems with the HV batteries, or so I thought. Initially, the car just would not start, but after sitting awhile, it would again start with no warning or engine lights. I checked the 12v battery at this time thinking that might be the cause and it was not. We went months without this happening and then again, car wouldn't start. However this time the car was completely dead. Jumping it wouldn't even get it started to move it onto a flat bed.

I got the Prius to a certified Hybrid mechanic who did some diagnostic testing and told me that I had a bad fuse block block and a few bad cells in my HV battery pack. He then proceeded to quote me $3400 to fix the car. I did some research online, mainly using this website, and use the information to find the two HV battery cells that were bad. By bad, I mean lower voltage that the rest of the batteries when testing. I replaced them with new batteries that were purchased off eBay. I then proceeded to recondition every battery by fully charging and then discharging 3 times using RC car charges. It worked great. From there, we made a wire harness to balance all of the batteries. All cells were around 8.07v when the HV battery was place back into the Prius. The 12v battery is newer as well and I also made sure that had a fresh charge as well.

I reinstalled the HV battery system back into the car. The blown fuse panel was also replaced prior to putting the orange HV relay back into place. I turned on the car and everything fired up. The battery was reading full on the screen and everything looked great. The red triangle was on initially but that was fixed by repositioning the orange HV relay. The only code that was left on the dash at that point was one for the throttle positioning sensor. Even with this code on displaying the car seemed to be running fine at that point.

A day later I came back to install the rest of the plastics and I when I went to drive the car back into the garage I noticed the HV battery charge on the screen was saying that my voltage was dropping. The engine was running, the car was attempting to charge HV batteries but it didn't seem to be working. In a matter of 10 mins, with no accessories (heat, AC, radio, etc.) on my Prius went from down to 2 bars on the screen. The car kind of sputtered when I turned it on to drive it into the garage but I thought that might have been from sitting for over 1 month without running. It resolved shortly after without any intervention. However, the batteries did not seem to be charging.

I am at a loss at this point. The only code I have is for the throttle positioning sensor. I have not replaced this yet but I can not see this being the cause. I have no idea where my power is going and so fast. I didn't attempt to drive the car other than in the parking lot due to the fact that I did not want to have it towed again. What do you guys think? I have searched forum after forum without any luck. Any input would be greatly appreciated.

 

A little over 100,000.

 

I agree, the cells I changed could be bad but I do know the RC chargers we used work as they have been used to charge and balance Prius batteries in the past with success. I will look into the MiniVCI though as it is looking like I will be starting this process over.

 

You are right, I really do not know what I am doing. I have attempted to research this, but as with anything, there is a lot of useful and useless information out there. I'm am going to do more looking into the MiniVCI. Where could one purchase this? About how much do they go for? Are there any good links on this site that explain better how this setup works? Thanks

 

I bought the MINI DVI and downloaded techstream. This is all of the information that I was able to obtain. Please let me know if you can shed any light on these codes or while my Prius is still not running. Any help would be greatly appreciated.

Justin

 

Thanks for the help. I will look into these things.

Where would I look on techstream for the INF codes? As I'm sure you can tell, this is all new to me. This is my first Prius and I'm learning as I go. Thank you for the flowchart. It seems as if there is a lot of valuable information there.

 

The 12v battery is charging as we speak. Tomorrow I'm going to see how long it holds charge during testing. The 12v is a optima yellow top that was purchased in 2013. I don't suspect it to be bad already but I know that batteries can go bad in 2-3 years.

I will ensure that I inspect the traction battery interlock switch making sure it is engaged appropriately. Any tips on ensuring it is engaged? Also, where can I find the inverter cover switch? Is this something that I can test? I have a feeling that my inverter is failing. My engine will run and my display will show that the engine is charging my HV battery. However this is not the case. After a short period, the engine starts shaking more dash lights come on.

I will also check the fuses associated with the throttle position sensor. I also just plan on replacing this sensor in its entirety as well. I will look at the throttle plate and throttle body interior as well. Looking in the throttle body today through the air filter, I did not quite a bit of carbon buildup. I had planned on cleaning that tomorrow. I'll let you know what tomorrow brings. Thanks again for the info

 

So this morning I ensured that the traction battery interlock was properly installed. I then checked the fuse Patrick reccomended checking. Sure enough, it was blown. Once the fuse was replaced the car started running normal again. Amazing how that works. Now I just feel like an idiot for not checking my fuzes first. I was able to get rid of the C2318, P0A0D, and P2118 codes. I now have no codes in the HV battery, and Engine and ECT. I do still have the code "B1248 AVC -LAN Communication Impossible" in Gateway. And in Hybrid control I am throwing the code "P3000 Battery Control System". In Air conditioner I have code "B1421 Solar Sensor Circuit (passenger side). In the Power Source Control section I am still throwing the code "B2271 ignition hold monitor." If you are able to shed light on any of these codes please feel free to help out. I appreciate everyone's input thus far. My Prius wouldn't be running if it weren't for you.