P3000 hybrid battery malfunction-urgent, need help!

Hello and welcome to PriusChat.

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Your code reader is not getting all the codes, I'd expect to see P3030 as well.

You need to buy a new wire-frame harness no. 2 from your local (or online) Toyota parts counter which is reasonably priced. In addition, reinspect the socket in the battery ECU. If any of the pins (especially around the area of pin 22), find a secondhand one with a good socket and replace the ECU as well. Get an ECU with the same part number as printed on yours, or you could use a part with a newer part number as well. Use Toyota Parts Center Online to find the latest part number, just type in your existing part number into the search box.

Once you get this sorted, see what you are left with.

You talk about balancing modules, but you are using that term incorrectly. What you are talking about is equalizing and as far as connecting the modules in parallel equalizing is a waste of time. It is true that all the modules should be around the same voltage (within 0.2 - 0.3 V) when the battery is assembled, but this should be a byproduct of correctly rehabilitating the modules. Balancing is a charging/discharging process where your overcharge (at the gentle rate of 0.05C (325 mA in the case of the 6500 mAh Prius modules) 3 - 5 times each time going to a lower level of discharge (lowest being 0.5 V per cell or 3.0 V per module).

The last point I'd make is you are really pushing it uphill changing twenty-two modules. This whack-a-mole approach only really works one or two times changing four, maybe six, modules maximum. I don't know what criteria you used to decide twenty-two were 'bad', but if you didn't do a capacity test or a load test and only used open-circuit voltage, then you might be throwing out modules that are otherwise ok.

You need to charge all modules up and do a top balancing charge first on all modules, including the modules you think are 'bad'. You then need to record the max voltage, let them sit for a week or more, then measure the OCV again and record that. Alternately, if you can't spare the time you can do a load test.

You should make good use of spreadsheets to record your results. It helps immensely with evaluating which modules are good vs bad.

There are plenty of posts in the Gen 2 forums that describe both balancing and load testing, so I'm not going to go into great detail about that. Use the Advanced Search feature to limit searches to the Gen 2 forum and its child forums. Pay attention to any post by TMR-JWAP, ericbecky, strawbrad, and PriusCamper.

Good luck.

 

+1 to dolj

You have some type of problem with the small wires that the battery ecu uses to sense block voltage. Could be the wire harness, could be corrosion damage to the connector and pins at the ecu (fairly common), could be loose and/or corroded connections at the battery modules.

Did you: clean the busbars and nuts and torque them to 48 inch pounds? Inspect yhe orange connector and connector pins at the ecu? Clean and inspect the small wire terminals at the module studs?

I also am of the opinion that "just" changing 22 modules has a very low chance of working correctly. I would expect to get "block xx reads weak" - P30xx codes soon after you straighten this other stuff out. Now if you took a complete set of known good modules from another car and swapped them all- that should be fine.

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