P0A80 Code- but is it really the hybrid battery

Yes, I sort of thought it might be like that, until he went and brought in P0607, which really is from the (actual!) ECM.

In general, because a gen 3 Prius has about two dozen ECUs in it, it's ok to just say ECU when it doesn't matter which one you're talking about, but when it does matter, you've gotta say which one you mean.

And it's best to reserve ECM for only when you are talking about the engine control module. The ECM is one ECU, but every other ECU is not the ECM. Only in ECM does the E stand for engine; in ECU it stands for electronic.

 

First you need to find out exactly what is wrong with the hybrid battery assembly before you replace anything.

I am a little confused by the three P0A80 codes that you posted pictures of back in post #27. One of them says it is a pending code, one is a stored code, and one is a permanent code. The stored code also has the freeze frame data that you posted. I am confused by the stored code, I do not understand what a stored code is. Toyota's TechStream lists trouble codes as Current, Pending, or History (permanent). So I do not understand what the Innova 3160RS scanner is calling a stored code. If I have time, I will do so research on it.

Do you presently have any of the warning lights on your dash or is the hybrid battery cooling fan running at full speed? If not, I do not think that you have any current trouble codes. Just drive the car like you normally do, but keep the scanner close by.

 

Is the hybrid battery cooling fan running at full speed? You should be able to hear it easily.

The Delta SOC is showing 36%.This value should be 0.00% for a healthy battery. This is the state of charge difference between the best and worst battery blocks. This suggests that the battery blocks are out of balance with each. A top balance with a grid charger may be all you need to do, but more analysis of your battery needs to be done.

No, but if you are curious about what result you would see for your battery, you can buy it. I am not sure what the cost is now. I purchased it about 3 years ago for ~$10US.

The other parameter to watch closely is the voltage difference. This is the voltage difference between the highest and lowest block. That is what triggers the P0A80 trouble code. You should have someone drive your car as you watch the app and take a few screenshots when you see 50 to 80 amps of charging (during regenerative braking) and the same for discharging (during acceleration).

 

Weird. If there is a PID for the boosted voltage inside the inverter, those would be believable readings for that, but as battery voltages the 620 and 400 have to be bogus.

 

Bogus as in shouldn't have been seen. Puts me in some doubt about what Dr Prius is really doing there.

The app once had a bug in DTC decoding that got fixed, but that was different; I'm not sure how to explain this.

The CAN protocol includes checksums, so garbled messages shouldn't be a thing....

 

Those are some wild screenshots of the Dr Prius app data. No the battery pack voltage should not be changing from 190-250v rapidly. Can you please check you trunk for moisture or water leakage. Corroded connections can create some unbelievable data in the Dr Prius app.

Do you mean you used the EV mode? I would not do that until we figure out what is going on with your HV battery.

Try using the app to read the trouble code and please post what was found.

The first three screenshot show some wild data. The fourth screenshot (pack voltage= 225v) is more normal. Did you happen to close the app and then restart it before the fourth screenshot?

I personally do not have any experience working on the HV battery. What I know has been obtained by reading this forum. Hopefully someone will see this thread and chime in that has some experience with a problem like this.

Maybe ChapmanF can answer some of my questions about the battery ECU.
1. Besides the voltage sensing wires from the battery modules, what else connects into the battery ECU. I believe that there are a total of three connectors.
2. Does the battery ECU connect with the hybrid control ECU or does it connect with some other ECU?

So, something is going on with the controls for the battery pack. I would be very surprised if any of the battery modules are bad.

 

Delta SOC should always be zero.

Whatever that number is other than zero is how much the battery is overcharged.

I would say you need a new battery.

 

Can you please explain why we are seeing all the other weird data as seen in post #47 Dr Prius screenshots?

 

Doesnt matter that battery is trash.

What data are you worried about Brian?

When your car is running the ICE while the HV battery is full, it is trying to drain the HV battery because it is overcharging.

Delta SOC should be zero.

You could try draining the HV battery until delta SOC is zero but watch pack voltage and keep it no lower than 220v

But if it is an old OEM then its time to replace it already.

 

Agreed. I wrote about this in post #44.

Wrong. I will quote what I wrote in post #44. "This is the state of charge difference between the best and worst battery blocks. This suggests that the battery blocks are out of balance with each."
The image below is taken from the Dr. Prius App website:

I do not understand what you are saying. Can you please explain this a little more so that I can understand.

Maybe it is time and maybe it is not time. It could be that the battery ECU is faulty and replacing it would fix the problem. Why replace the complete battery for 3,000$CAD when a used 250$CAD battery ecu could fix it?

More diagnostic work needs to be done on this battery to determine why the weird data is being displayed in the Dr Prius app. Hopefully, someone has experienced something similar to this before and will contribute to this thread. That is the reason for this forum.

 

They changed things up a little in gen 3. In gen 1 and gen 2 there was a full-fledged Battery ECU that had its own network address, distinct from the HV control ECU, and you could talk to both. They both had their own codes.

In gen 3 they don't call it the Battery ECU anymore, it's just the "battery voltage sensor" or the "battery smart unit". It connects back to the power management control ECU over a dedicated serial link, and whatever codes or live data you read on a scan tool, you're reading from the power management control ECU. The smart unit is just kind of a remote sensor annex for it.

In the 2010 wiring diagram, there are three connectors shown on the smart unit: c1 where it connects to the car (12 volt power, ground, the serial link to the ECU, the battery current sensor, and the battery blower speed monitor signal), j1 (all the block voltage wires; this connector is orange), and z17 (the four thermistors embedded in the battery stack). The fifth thermistor, the overall "HV battery temperature" one, is wired directly to the power management control ECU.

Yeah, it's a little weird, one thermistor wired directly to the ECU, while the other four go through the smart unit. Also, the battery blower control signals are wired straight from the ECU, while its speed monitor feedback goes to the smart unit to be communicated back to the ECU over the serial link.