I have a 2004 Prius with 119,000 miles (whole time in NC as I have learned location affects battery life). This summer the car wouldnt start on a number of occasions and had to jump it. I asked the mechanic to check the 12v battery and they said it didnt need to be replaced. Last week I had the red triangle light, check engine light, and yellow tire light come on. Mechanic told me we had to replace the traction battery (paid $3,200). Did that and a week later the car wont start (started once when jumped, but didnt charge). A faint yellow check engine light is on. It seems like the 12v battery is dead. Is it possible it was always an issue with the 12v and that I didnt need to replace the traction battery? What info would help you know the traction battery definitely needed replacing? I am worrying that I didnt ask enough questions of the mechanic and want to be prepared when I take the car back this week.
Most likely it has always been the 12V battery. I would look for a mechanic more familiar with Prius to take care of the car if I were you. Good luck! And welcome to PriusChat. Lots of good info here.
My friend has a 2004 with 235,000 miles and he is still on his original traction battery. Thats not to say yours was good or bad, but I tend to lean on this mechanic just didn't know how to properly diagnose your car. Are we talking just some local mechanic who checked out your car? When it comes to something that expensive and the car really not having many miles, taking the car to someone who really knows how to properly diagnose it would be best IMO.
Hi Melissa, welcome to the forum. Chances are it was the 12v accessory battery that has/was the issue. The problems were there that would have been a clue........needing a jump. The Prius relies on the 12v accessory battery to turn on all of the relays that switch the power source to the traction battery. I would go back to the shop & demand that refund the cost of the TRS tion battery since replacing it didn't resolve the original issue. If they don't want to budge, threaten them with a law suit for makeing the wrong repairs. U might need to go to the dealer & get the proper repair as proof that this other shop was wrong & ripped u off.......but doing so is eaiser said than done. Good luck.
Traction battery was probably fine. If battery still took full charge often then it was not the issue.
While I agree the 12 volt battery is almost certainly dead have you checked that it is being charged. Voltage should rise to 14+ volts when car is made ready, if not suspect the DC to DC converter.
The traction battery has been replaced and now there is a question of whether that was needed. Other than wondering if the diagnosis was correct, what evidence is offered that the replacement was not appropriate. If someone knows how she can prove that replacement was not necessary, it's time to come forward and offer some advice. It might be too much to hope for, but possibly the battery remains in the shop and could be tested.
Yes, unless there were other issues that you haven't told us, then it is very likely that the 12V battery was the only problem all along.
Thanks for the replies. I was trying to get at understanding if the traction battery was indeed dead - would there have been a specific code? After reading the posts on this site, it sounds like the same warning lights that I had can mean a variety of things. They spent about 1/2 hour diagnosing the car. Of course the shop says it was needed and they already sent off the old battery. This is a shop that specializes in Toyota/Honda, there arent really any Prius specialists that I have found in Raleigh, even the two Toyota dealers inthe area have been unable to answer some of my questions in the past in regards to the Prius.
Hi Melissa. The problem is that with the 12V battery in such poor health that it is unable to even start the prius, then any codes etc that it was throwing could have been erroneous. People here have documented the 12V battery falling as low as 10.5 volts and their Prius still starting and running. This means that your 12V battery was probably very bad indeed, and trying to diagnose other problems with such a poor 12V battery is very likely to give unreliable results. In most cases, if your traction battery was failing then you'd notice some very specific driveability issues, none of which you've mentioned. On the other hand, the frequent non-start and jump-start requirements that you do mention clearly indicate the 12V battery and not the traction battery. I feel sorry that this has happened to you, and I know that the shop won't admit their mistake. If only you had come to these forums and gotten advice before getting the work done.
They told me it was unsafe to drive the car so I was stuck doing the repair. I intend to bring this up with them, at the very least so they dont do this to someone else. In addition they sent the battery somewhere for disposal - I wonder if they can get it back? I will definitely look through the forum for advice on new issues. Thanks everyone
Yes. For example, DTC P0A80 means that the traction battery needs to be replaced. If your service invoice shows the DTC that had been logged, please post those and we can interpret what they mean.
Hi Melissa, I live n Fuquay and just replaced my traction battery with a used one from a car with 80k on it to replace mine with 242k on the odometer. It's doing great so far. I had some concerns after having it installed so I took it to Taylor Automotive in Sanford NC... not too far from Raleigh. They have the experience and equipment to diagnose your car. They only charged $70 to check mine out. Fortunately for me, everything was fine. I suspect you only needed the 12 volt battery. Good luck!
I asked for the error codes today and it was P0A80. Also to note, the 12v battery appeared ok that day. Yesterday when they read the 12v battery before replacing it, it had a reading of 12.3. On Aug 22 the reading was in the 14s. So it looks like they were right from other posts I've seen regarding this code. I have definitely learned a lot on this site and will continue to visit it. I plan to drive this for a long time - get my 3200 dollars worth! Hopefully this one will go more than 119,000 miles
Actually that just means that they don't know how to correctly measure the battery voltage. The 14V that you quote is just the DC to DC converter voltage, it doesn't really tell you much about the 12V battery.
What a mess. Can you describe, in as much detail as possible, the events and symptoms leading up to the battery replacement? Did you notice the traction battery level on your display going from full to empty rapidly in the days leading to the replacement? Does your original receipt have the P0A80 written on it?
Car has been working fine all along. Earlier in the summer the 12v battery wouldnt start the car - happened a couple of times, mostly if the rear hatch hadnt closed all the way and the light was on all night. I thought the battery might be bad and had them test it in August and they said it was ok (the printout from the machine showed full charge). The day (about a week ago) the warning lights came on (red triangle, check engine, and yellow indicator for brakes) I was surprised. The car drove fine for the couple miles from my house to the mechanic. I was afraid to turn it off and be stranded (two toddlers in the car). So I didnt really have any symptoms of the traction battery failing. I dont usually have the screen on that shows the battery level so I really couldnt say if the the battery level was fluctuating. My original receipt doesnt show the code but I have seen the paperwork the mechanic filled out and it showed the code.
