The Hybrid battery does not charge. It has happened twice so far and I am concerned that this will become a larger issue. The yellow triangle does not appear. In fact the only indication is that the battery bars drop to two and the charging bar indicator shows no charge . When I stop and turn the car off then turn it back on, the charging goes back to working normal. Has anyone have this happen in their Prius? I have a 2010 IV with 97000 miles.
The hybrid battery does not indicate an increase of bars when braking. The battery drains down to 2 bars and does not increase. The charging indicator does not show charging while driving/braking. Shows no codes or problem lights on dash.
Based on your join date, I'm assuming you have plenty of experience with this car so it's not pilot error. I think I'd be taking it to Toyota or a trusted hybrid specialist to let them check it out. Something sure sounds strange.
So, you're saying this display never goes into the CHG portion? It should definitely enter this portion when braking, and possibly during coasting also.
I have this same problem too in a Gen 2 Prius. In a conventional cars charging system you would suspect the voltage regulator in the alternator, but since the Prius uses the Synergy drive as the alternator and a CAN BUS system to control the charging you have to troubleshoot more things. I noticed using Toyota Techstream diagnostics that the 14 voltage inputs to the Battery ECU coming from each 2 cells in series of the Hybrid battery pack were even voltages and would normally rise and fall while charging and discharging so no problem with the battery cells. I noticed the software shows a State of Charge SOC of the battery which is in % which was not in sync with the voltage rise and fall of the battery cell voltages. So in other words if the voltage of the hybrid battery increased, the SOC signal which is sent through the CAN BUS ( Control Area Network) to communicate with the other modules was not reflecting the increase the voltage charge of the Hybrid Battery. Sometimes I would be driving and the display would show the bars dropping or sticking in one place like 2 bars never going up or down so I suspected the Hybrid battery voltage or SOC of the battery sent through the CAN BUS was lost or not communicating properly so the rest of the modules including the Hybrid ECU which controls the inverter, did not know if the battery was charged or not. When there is a problem in the charging system the battery ECU is designed to stop charging the Hybrid battery, at some point it will throw a code, mine were P3000 generic inverter code and generic P0A80 bad hybrid battery code. .I had tested my 12 battery, it was good, NOTE if it has low voltage when the car is powered off, it can cause codes to be thrown since it is only used to power the cars computers or modules. It was eliminated being the problem first, being easy to check. So when I reset the vehicles modules by unplugging the large wire to the 12 battery and reconnecting it with the car powered down, just like the guy in this post, when I powered it back up, the bars prior to unplugging it that showed a low Hybrid battery charge would rise to show a full charge or much higher normal charge. This happened without the engine starting, so I know the full charge was in the battery when it showed 2 or less bars. So to test specifically the battery control ECU the next time the display showed it not charging, I unplugged the connector on the rear of the battery pack ECU module which powers the module, and upon powering the car back up, I got the same results. So I did isolate the reset which caused the display to show the actual charge of the battery to being the the battery ECU. So my conclusion is the Battery control module which converts battery charge inputs in voltage into a CAN BUS signal output which communicates State of charge in percentage to the other modules was not being properly communicated to the other modules which is why the module that drives the display showing the battery charging level in bars, was not accurate, or sticking. And since the inverter is the other ECU involved in charging the Hybrid battery I suspect that is why it also threw a code. I did check the CAN BUS pin connections only at the battery ECU for corrosion because the back hatch on Prius cars are known to leak when it rains, they were good. I did not check the pins at the CAN BUS module because it is less likely to get wet and corrode. So at this point I have ordered the Hybrid battery ECU because it is the main link in converting the battery charge in volts into a frequency to communicate the percentage of battery charge to the CAN BUS, where it seems to be unreliable. The triangle of death can be caused by many different codes which do not have to mean the need for replacement traction battery unit cells which are the expensive part. I was getting the P0A80 replace hybrid battery code with this charging problem which is intermittent. When it is working properly I am getting 55 MPG which you can't get with bad battery cells. So when I get this charging problem fixed, I know my mileage will be in that range. I will come back and do a reply to this post since they do not allow edits after 15 hrs and let people with this problem know if it was the Battery ECU causing these symptoms.
@ilbdarned5 The reason why you are getting different HV battery reads on the screen has been answered in post #3 in the thread you created for the problem with your car, https://priuschat.com/index.php?posts/3550488 Please keep all discussions about the hybrid battery problem in that thread. Thank you.
