2009 Prius with 133K miles.12 V battery was changed 3 months back and also Inverter Pump was replaced recently. While on the road driving in the normal traffic, saw the red death triangle coming on. I kept driving and then the cooling fan came on loud enough that I can hear the buzzing sound. Came back home and checked the codes using a generic OBD reader and found PA080 (Replace Battery) and P3012 (cell 2). I erased the code which resulted in Red Triangle disappeared. I did not drive this after this so not sure if it will come back. Do I need to replace battery or it might be something else that I should check out before jumping on HV battery? Thanks
Hello and welcome to PriusChat! What you describe is most likely a failing HV battery. You could get a "better" scantool device and monitor battery block voltages to confirm. Here's a post that reviews several scantool options. There are several I would use for general diagnostics (ie capable of checking codes and data on all systems on your Gen2 Prius). For specifically looking at HV battery data, I would look at the Dr Prius app with a compatible bluetooth OBD2 adapter. There's several adapters listed on the Dr Prius site (I use the BAFX Products adapter with my android phone). The HV battery has 14 blocks, each block has 2 modules (28 total), each sealed module has 6 x 1.2V cells - all in series for a nominal voltage of 203V. The ecu monitors the voltage of the 14 blocks, and will set P0A80 if the difference of any block is "too high" for "too long". (Normally, the difference is never above 0.3V for more than a few seconds) Typical failure is one cell goes "bad". Usually you will see the voltage for the affected block will be 1.0-1.5V lower than the others when accelerating hard, and it will go higher than others when decelerating. The most reliable repair is to get new battery pack from Toyota. Occasionally you see corrosion damage to the HV sense wiring at the battery ecu, but voltage readings won't look like the "usual" failure. https://priuschat.com/index.php?posts/3290690 Posted via the PriusChat mobile app.
Thank you for your comments. It makes perfect sense to monitor battery block voltage to confirm the issue. But I'm wondering if there are any other technical reasons resulting in theses codes (PA080 and P3012) ?
The repair you make and how long it lasts is defined by what you can afford. The cheapest fix is a replacement module for $35 from: Hybrid Car Battery Distributor | Contact Us | 2nd Life Battery and you do all the the work. The most expensive fix is a brand new pack over $2K. There's lots more in between that too. Let us know more about what you can afford and if you or a friend of family member wants to DIY some of this... In the meantime, you can keep driving your car and clearing the red triangle as it comes up as long as you don't let the battery pack overheat, which won't be too much of a concern until the weather heats up again.
You can keep driving and clearing the code until the bang and bad smells from the back of the car, at which point you walk home. The bang depends more on what's going on right inside the particular module that goes bang than it does on anything quite as predictable as outside weather or the battery pack as a whole overheating.
Yep... But you can use a phone app to monitor pack temperature, which doesn't protect you 100%, but pretty close, especially in Winter.
The thing is, the temperature is monitored by only a few individual thermistors, stuck into the thermistor wells of just a few of those 28 modules (plus one that hangs out in the "inhaling air" stream). Because a particular module going bang is so specific to the internal conditions of that particular module (including, but not limited to, its temperature), if that one happens to be one of the few out of 28 with a thermistor poked into it, you might get a bit of warning, if you're watching closely enough. Otherwise, you're just seeing the temps of a few modules that aren't about to go bang.
After 5 years of driving around with failing battery packs in order to diagnose bad modules that's never been a concern to me, but that's because I'm doing it to study the pack and have the ability to remove it soon as there's a warning sign like a temp sensor soaring unexpectedly. And yes, to your point, if you're just doing this because you're ignoring the problems the pack has rather than making preparations to repair it, that's asking for trouble, especially if we aren't just talking about short trips around town. As I've often explained, electrons are weird. Sometimes I've had failing packs I've put in that will throw the red triangle three times in a day and then go three weeks without issue. So yes, be cautious, but studying a packs behavior prior to rebuilding it isn't something I'm going to stop doing because it offers valuable insight, despite some risks.
Thank you all for your input. I don't think that kicking the can down the road is a solution. Since this is over 10 years old car, I'll just go with a rebuilt one. Individual cell replacement will be more costly.
Not that I know of. What limited information that Toyota released about those codes states that they are set when voltage differential "exceeds threshold value". So you have: the battery modules, the battery ecu, and the wiring or connections between them. Once or twice I have read about problems resulting from module busbar connections that were loose (or not cleaned before reassembly) - but that's "user error"- improper technique following a DIY repair. Posted via the PriusChat mobile app.
