False Positive P0A80? - Replace Hybrid Battery

Hello all,

Recently my 2nd gen Prius has been acting, strange. I hoping to get some insight to the best way to fix the problem, so I will include as much detail as I can. Please bear with me

Over the weekend I went to go run some errands and while I was leaving my neighborhood, my dash lit up like a Christmas tree, with the red triangle, CEL, low tire pressure, and the exclamation on the MFD. So I quickly turned around and parked it back in my garage.

A little later and after doing some research on the forum here, I began to troubleshoot, at which point the feeling of dread was at the pit of my stomach and decided to go to the local auto store and have the code read. It was of course the "P0A80 - Replace Hybrid Battery Pack" the exact message I didn't want it to be.

So I turned around and went back home, the entire time all the lights stayed on and monitored the SOC of the traction battery. It was charging, just increasing and decreasing quicker than usual. (arghh).

So upon arriving home I started by popping the trunk and with the hope to check the voltage of my AUX battery, upon doing so I noticed that my (aftermarket) Alpine subwoofer amp was on, which it shouldn't have been! So I go ahead and check the switch I installed and sure enough it's on. So now I am thinking, "that might have been the problem!' So I completely disconnect amp from the AUX battery, and disconnect the AUX battery. I check the voltage and it's at 11.1V. So I pull out my batter charger and hook it up. The plan being I'll charge it overnight, take off the charger in the AM and let it sit all day and check the voltage again that evening (10 hours later).

So I get home that night, hook up the battery and check the voltage via the dash display and they all come in within range. Sweet. And of course since the battery was disconnected all the error codes (lights) on the dash have cleared. So I decide to take it for a spin.

I drive around for a good 15 minutes, and everything is acting normal, traction battery is charging/discharging normally and no lights come on.

Now comes yesterday morning and I have decided to take it to work, thinking it was just the AUX battery being low. I start driving, all good. Then I get to a stop light (10 min from home), and as normal the car shuts off, I currently had the following items on; radio, front and rear windshield wipers, rear defroster, heated seat (aftermarket), radar detector, radio and a bluetooth transmitter plugged into my cig lighter. (yea I know). So as I come to the stop, again my entire dash lights up, crap.

I quickly get in the right turn lane, so I can turn around and notice I have no power! My ICE is completely off and I notice my SOC at two bars and dropping, so I quickly pull over throw the hazards on and turn the car off.

Crap. So at this point I decide I will turn it back on, if the ICE still stays off I will get a tow, but luckily it turns right on, dash is still lit, but it's driving so I take it back home and park it in the garage.

Now to last night, I hop back in the vehicle to do some more readings on the AUX battery voltage. The first time I do it, dash warning lights are still on and AUX battery voltages are still in range. Then I do it again, but this time the entire dash is normal, no warnings at all!

Some details:
- Unsure of AUX battery age, it is OEM, though.
- 211,000mi
- Regular maintenance schedule followed, since I owned it, I am the third owner.
- Last oil change the tech noted that the coolant pump (? ) was leaking, which upon researching here is normal under most conditions.

AUX Voltage readings for every "stage" (each were +/- .1 -. 2v):
ACC - 12.3v
ACC w/ load - 11.9v
On - 14.0v

So I plan on ordering the Optima Yellow top, as I am due for it anyway and everyone here has said that if you even think it needs to be replaced, replace it.

Thanks again for your time and help.
-Dave

 

I do agree with that statement. And I am not looking forward to pulling and testing the cells, which seems to be the most economical choice.

I guess the only thing throwing me off is when the ICE wouldn't/didn't run, does anyone have any idea if that would be caused by the traction battery failure, or could that maybe point to the coolant pump, or something else?

I have seen many different options for replacing the traction battery, either entirely, by bad cell, or as nh7o mentioned grid tied balancing (which I need to read up on). If I do decide to pull it out and test each cell, what is the likely hood of needing to do it again very soon (another cell failing)?

Also if I choose to replace the entire pack, what is the best route to go; used, re-conditioned (?) or new?

Sorry for all the questions, but I really do appreciate your knowledge and feedback immensely!

Thanks
Dave

 

OK, so I contacted Steve over at AutoBeYours and picked up a "new" battery from him. Granted it was a 10 hour round trip drive, but in my opinion, well worth the trip, his shop is like a Prius graveyard, with parts and more parts. Honestly it was a lot of fun!

Anyway got the battery installed yesterday morning, and everything worked great!

Before the battery was replaced I was pulling around 43mpg/tank, today on the way into work (30mi) I averaged 58! I am very pleased this all worked out with a little elbow grease and much less $$ for a new one ($3,800 from my local dealer).

Another side note, the AUX battery is a Toyota "Premium" battery or whatever its called, and apparently has very long warranty (7 yr?), unfortunately I have no idea when it was installed. I've looked through the service records online, but could not locate it. Is there anyway to find a manufacturer date on the battery? Or would it be better to take it to Toyota and have it checked?

Thanks
Dave

 

Good know! Thanks