P0A80 Help/Suggestions

Helping a friend with 2010 Prius III (Gen 3). He got 155kmiles on it and he got the P0A80 in past July. I told him that it could be a battery module going bad. We resetted the code and he drove the vehicle. In a few months, the code appeared. I offered my help and we removed the battery cover to check each of the 28 module voltages. All voltages ranged between 8.11 and 8.21volts. This wasn't what I expected to see.
I didn't settle with that and I load tested all of the individual modules. I ran a 12 volt electric starter motor for about 5-10 seconds continues on each module and all modules showed between 7.9 and 8.0volts which is perfectly fine. There was no module losing voltage under load.

I went to run his car and watched the MFD and realized something weird. The car was NOT charging the battery all the time. This happened even when there was just 2 bars showing in he display. The car was at "P"
I waited for several minutes and then it started charging for a few minutes and then stopped again.

Mine doesn't do this. It charges almost all the time if the gas engine is running or it shuts off the gas engine.
He also told me that while driving he realized his Gas engine is constantly on (never shuts off as it used to)

So he has a different issue. Most likely related to the charging circuit. I checked the inverter coolant. It was slightly below "Low" I will fill it up now but I doubt it is the problem.

What else could this be? Any ideas would be greatly appreciated.

Thanks

 

Another observation (if it may help), a pump (that sits behind the inverter coolant reservoir) keeps running every 2 to 3 minutes for about 5-6 times every time the driver's door opens. It may be the brake booster pump (same sound) but mine does it one once and stops. On his car, I hear it more than several times.

 

Yes, I kind of guessed that after posting it. The same sound. The only difference as I mentioned above, mine runs for 5-6 seconds and stops. His car (after the initial 5-6 second run) keeps repeating this for 5-6 times at every 10 seconds (each boost lasts for a second or two). Mine doesn't do that. But that is a brake related issue. Shouldn't have anything to do with this.

I put his car together, topped off the fluids (about a cup for Inverter coolant and maybe 2 cups for the radiator coolant). Took it to a test drive. The car performed just fine. It was charging the batteries when the engine was running (It was NOT chaging in the morning.) But it always start like that. I am sure the P0A80 will show up in a week or two.

I do not have the Techstream but I do have some generic OBDII readers. It won't provide a valuable Freeze Frame data. There was no code present when I scanned it (we cleared the P0A80 a few weeks ago). After the scan, P0A80 was showing as "Pending". So it was a matter of time for it to show up.

Would Torque Pro (paid version) or Dr. Prius (Paid version) help in anyway to diagnose the issue?

 

Man, I wanna make you my Real friend and come visit you if I ever get this code on my Prius.
How about that?

 

So, no suggestion on this what so ever?

Anything?

 

Hi Ray, my apologies. I forgot to answer your question earlier. The both bus bars were looking fine. I didn't remove any of them. Some occasional green stuff on several modules but overall they were fine. We used a plastic brush to clean them.

I didn't remove the battery pack from the car. I did everything while the pack is on the car (the orange breaker was out obviously).

I will talk to him about your recommendation. Between you and TMR-JWAP, it seems you guys still focusing on the battery module.

 

Man, thanks for the valuable info above. Both of you recommending the Techstream. I will give that a serious look for sure.

I started to think that I should repeat the test when the battery modules are at low voltage. When I did the test, all modules measured over 8volts. Maybe they would have behaved differently if they were at the low end.
Also I may think about using higher-amp load. Like 5amp continues load.

I will also check those Hybrid Assistant/Hybrid Reporter app as well. I was so sure that the most helpful app on the market for Prius is Dr. Prius so far. I guess I was wrong.

 

And as always, I will absolutely report back with every little update. That's what I always do...