2005 Red Triangle, P3000...

Greetings!

Looking for help troubleshooting my 2005, 140K miles, I am the original owner. Car has been spending the spring sheltering in place, with only weekly trips around the neighborhood for exercise.
I am not a great mechanic, or any kind of engineer, but I can generally work on cars and at least do no harm.
The weather got hot, and The Bloop went all red triangle/warning light christmas tree.

I had this happen before (2018) due to hot weather, neglect, and a low 12v battery. This time 12V measures low, fresh charge in the 12V (to a steady 12.6V and a passing grade on a load test) changes nothing.

I obtain a Veepeak OBDII reader and the Dr Prius App. I am expecting to see that the battery is toast.
Shows P3000 code only. Battery Control Unit
Dr Prius shows the battery modules are all in the 7.6v neighborhood, except for #4 which is low, but module #1 alternates between positive and negative voltage every few seconds. This was an unexpected result. I shut it all down, disconnect the 12V and go inside to do more research.

I hone in on the cause of the crazy readings as the voltage sensing circuits and/or the battery ECU connector. As in here: p3000 p3030 | PriusChat
I dig into the back of the car, and checked the voltage sensing plug at the Battery ECU, look inside the Battery ECU, there is no evidence of arcing or corrosion of any kind. The orange connector is apparently not the culprit. Pin 22 is seemingly innocent.

My thinking on the next step is: Remove the rest of the cover and check the voltage sensing wires where they connect to the modules, particularly at module 1 (the furthest from the Battery ECU, passenger side).
Perhaps the erratic signal is from that connection, if not, then what?

Obviously, I would prefer to not rule out any simple sensor/corrosion/wiring problems before taking about performing a full HV battery transplant.

What else might cause the polarity oscillation readout in one of the modules? I'll check inside the case for corrosion or bad connection. I'm concerned about doing further Dr. Prius evaluations, which involve driving around, while something clearly abnormal is going on within the battery system.

Any advice greatly appreciated.

Peter

 

Thanks for your help, validation, welcome and encouragement.
In today's episode of before-it-gets-too-hot-to-work; me vs. Prius...

The cover has come off. I hope I can get most of those bolts back in the right order!

the sensing wire for #1 (the US passenger/starboard most module) is corroded through.
So there's my culprit as far as the goofy voltage readings. the other connectors look cruddy, but not like they're going to break.
I am tempted to try to repair the broken connector with a new spade and a couple of inches of wire. A used loom is about $75 on fleabay
What other options are there? OEM? Part #?

As far as the modules, there are a couple of iffy ones and one definitely weak:

From Passenger/Starboard/US Right side of car
1- 7.56v *
2- 7.69v
3- 7.69v
4- 7.70v
5-7.70v
6- 7.68v
7- 6.43v **
8- 7.68v
9- 7.72v
10- 7.69v

11-7.71v
12-7.69v
13-7.71v
14-7.72v
15-7.71v
16-7.71v
17-7.70v
18-7.71v
19-7.71v
20-7.69v

21-7.72v
22-7.71v
23-7.72v
24-7.71v
25-7.72v
26-7.69v
27-7.72
28- 7.58 *

I don't see myself investing in equipment to balance and condition etc etc.
If I fix the sensor connection, I am guessing the bad #7 will still be enough to throw a code.
If I replace just that module, without balancing etc, is that useless?

I'm torn between doing a sloppy home-brew wiring fix and putting all back together, or buying a new OEM battery, which I assume would include the sensor wiring to the orange plug at the battery ECU.
The price difference is stark, and I haven't worked a paid day since March 7, so you can guess which way I'm leaning.

Also, yes, I have cleaned up the cooling fan, and bench tested it.

Advice? Comments? Experiences?

Thanks!

 

Thanks TMR-JWAP and SFO. Lots of acronyms in the house!

I dusted off my soldering skills and grafted a new bit of wire onto the #1 sensor spade.
I reassembled and went for a drive. That repair held, and I only have one extra 12mm bolt. A small but Pyrrhic victory

It all stayed together for several minutes, no codes and smooth sailing, nice gradual charge and discharge - but on Dr. Prius block 4 is still reading as the most extreme voltage - low when resting or drawing, and highest when charging like on a long hill.
I tried the Dr Prius battery tests, drove up and down some hills to get some electrons pushing around.
I ended up with a new red triangle. the center temp sensor was in the high 130's, while the others were at 120..at one point I got a message that the inverter was too hot to force charge.
Codes are P3000 and PA080

I assume that battery overheating has to do the bad module, exacerbated by my aggressive driving.
MY UNDERSTANDING: The low rent course of action is to obtain one module (from where?) and replace the #7, keeping everything else the same, the order of the modules, etc. This would require disassembling the battery on a bench, but should get me back on the road for a little while. Probably..
I'll verify that the inverter cooling circuit is OK, pump and coolant.
Thanks for the part info on the wire frame # 2 as well, I'll have to get one of these.
The fan on battery is definitely kicking in. I will check the fan connector as well.

I really appreciate your hand holding on this

Peter

 

Thanks Edthefox5,

Sitting with this for a while, I think I don't have the energy to take on a new hobby (battery balancing).
I figure three modules plus the charger and power supply are going to be $300 ish. Plus the wire frame part.($60) plus ?
Plus battling the corrosion. Plus spending a week fiddling with it and hoping I don't get zapped and it doesn't burn the house down.
And ultimately, I don't want to put it all that work and have to do it again in X amount of time.
Ugh.
I think I will mothball the car until the $ starts to flow again and go pick up a new battery over the dealer parts counter

QUESTION: the OEM replacement HV battery includes the wiring to the modules. True or False?
ie. the orange plug that carries the voltage sensor wires to the battery ECU
If not, then I'll need all new bus bus, and wire frame #2, etc etc

The conversation in this thread discusses the OEM battery installation, but also mentions the module terminal torque, as if one would be installing the wire frame. Replacing the hybrid battery with a new Toyota battery | PriusChat

I can see that the OEM replacement does NOT include the battery ECU, and the other connectors etc that are on that side of the battery.


thanks

Peter