Gen II codes P01AF P3030 P3056

I am a long-time lurker who has decided to break down and join this forum. Thank you to all the posters who contribute and generously share your knowledge. I hope to one day be able to repay the forum.

I have been tasked to resurrect a 2004 Prius (250k miles) that has been sitting for a while. (Yes, I know ... don't let them sit without proper prep.) After getting some charge in the 12V battery and turning on the car, I was greeted with the circus lights (triangle of death, CEL, ABS, VSC, etc.) described in many of the battery problems on this forum. I was able to pull the codes:
- P01AF: Battery Energy Control Module
- P3030: battery voltage defective, line snapped
- P3056: battery current sensor circuit malfunction.
The car would not start.

I know P3030 is associated with poor connections along the bus bar. I believe this was the subject of a TSB in which the bus bars were replaced. I am speculating P3056 could also be caused by an open along the series of batteries. In isolation, I would assume the P01AF indicates a problem with the battery ECU. However, I am having a hard time believing 2 seemingly independent failures would occur simultaneously.

So, has anyone seen this combination of error codes? I would appreciate any sage advice or knowledge in this area before I start tearing things apart.

I also pulled the battery block data:
V01: 3
V02: -2
V03: 17 to 25 (varies)
V04: 16
V05: 16
V06: 15
V07: 16
V08: 16
V09: 15 to 16
V10: 16
V11: 16
V12: 16
V13: 15 to 16
V14: 15

V01 and V02 look obviously suspicious and support the P3030 diagnosis of a bad battery connection. (I read on one of the forums that the block adjacent to a bad or disconnected block often produces an erroneous reading so the V03 reading is questionable.)

My plan is to pull the battery out next week, disassemble and inspect it. I am hoping the problem will be obvious (e.g. corroded terminal) and that a good cleaning might bring it back without even replacing any modules. I do plan to balance the modules while the pack is out. If there is anything else I should consider, please let me know.

Thanks!
Marc

 

Hi John,
Thank you for the warm welcome and the advice. I have been reading many of your posts over the last few weeks and am elated to get a response from you! Also, thanks for the warning regarding the limit on posting pics.

I plan to take the battery out next Wed and I will take copious pics. Hopefully, it will be obvious how to ohm out the sense lines ... that certainly seems to be a likely culprit.

Based on your response, I take it that attacking the P3030 failure first is the best path forward. (?) It is certainly the one with which I feel most comfortable.

Thanks again! Marc

 

Sorry for going silent. I am not disinterested ... just don't have anything significant to report. I have ordered a variety of tools and supplies (lineman gloves, charger/balancers, etc.) for this project and am just receiving everything.

John, thanks for the suggestions. Maybe I will be so lucky that I don't even need to remove any modules from the pack! If I do need to tear it down, I'll watch out for the temperature sensor wires. I located and am acquiring a used battery pack (supposedly 1 bad module). So, I have some parts in case I need to start swapping.

I plan to measure the module voltages open-circuit and under load (as suggested in other threads). I will also try to measure the block voltages at the connector to the ECU. (Is this easy? Any experience here?) Hopefully, I can repeat the measurements provided by the OBDII reading.

Thanks again!
Marc

 

I have the battery case open and there appears to be considerable corrosion on the terminals. Here is the entire front bus.
The OBDII readings showed anomalous voltages on blocks 1,2, and 3 (modules 1-6). Here is a closeup of modules 2-13.


So, I believe there is a good chance corrosion is causing the problems. I don't see any breaks in the sense wires. I have the bus bars off now. I can/will disconnect the sense wire connector from the ECU and ohm out each line.

I popped the copper plates out of the orange carriers and have them (together with the terminal lugs) soaking in vinegar. They were looking good last night. In the mean time, I am going ahead to test out the modules as suggested by John above.

The open-circuit voltages of modules 1-24 was in a pretty tight range of 7.99-8.01. Modules 25-28 were in the range 7.79-7.81. Is there a common reason for such a bimodal distribution? Could the poor connections caused by corrosion have led to less of a charge on this modules? Based on these results, I would conclude there are no gross battery problems, e.g. dead cells.

To better assess the battery health (before charge cycling), I attempted a load test. For my first attempt, I used a standard load tester intended for a 12V Pb-acid battery. This probably was not a good idea as its lowest setting is a 50A draw. (That said, the battery module spec shows they can supply 10C = 65A but I have not seen reference in the forums to anyone pulling that kind of load.) This dropped the voltage on module one from 8.0 to 7.65V over a 10 sec test. I then stepped back to the method suggested by John/BritPrius & used in sideways rebuild thread. I connected a halogen bulb that pulled 1.8A (about 0.25C). Doing this, I saw voltage drops in the range of 0.04V which works out to an internal resistance in the 20 mohm range. (Correct?) The readings were consistent across all modules.

What is the conventional wisdom regarding the load pull? I saw jeffD's suggestion of 1A in another thread and I am wondering if there is a reasoning behind this range. My motivation is that I would like to pull something higher (maybe on the order of 1C to 4C?) in order to get better resolution on the voltage drop and, hence, a more precise internal resistance. (This is merely a practical concern as my Fluke 76 only has 4 digits of resolution.) JeffD, if you're reading this, your insight and advice would be most appreciated.

Sorry for the long-winded post.
/Marc

 

Thank you for the comments! I have read many of your prior postings. BTW, are there many hybrid fans in the town that builds Corvettes? (I remember taking a field trip to the Corvette factory in Bowling Green as part of my high school autoshop class.)

I am sorry that the pics I posted are not particularly informative. Here is a pic of the bus with the terminal nuts removed.
To your point, the copper looks pretty good under the terminal nuts in this pic. However, this is not the worst case. On the concerning ones, both sides of the copper plates were black with oxidation. I will get some pictures tomorrow if I have not already cleaned those.

So, I am hopeful that the modules can be saved. I am certainly not the hybrid battery expert that many of you are but I believe the internal resistances of the modules (and underlying cells) suggest they have some more charging cycles left in them. (I would love to see a chart of internal resistance vs charging cycles or capacity. This is pretty standard in other battery contexts but I have not found such info on the Prius batteries...I guess Toyota has little incentive to make that info public and it is pretty unfeasible to gather enough, i.e. statistically significant, data from users such as us.) I'm hoping to have definitive battery health data in a couple of weeks. I was lucky in finding an extra Gen2 battery pack so I have some modules available if it comes to that. (The seller of the pack reported that it had a bad block reported. The car had 140k miles on it when he had a new pack installed in his Prius.)

Regarding the rebuild in general, it is going ok. I am following the steps laid out by you and many of the other contributors here. I have measured the module voltages under load and am just starting the charge cycles. I bought 4 of the Supermate DC6 chargers and attempted to run 3 cycles last night on 2 of the modules. It was finished already this morning which it should not have been. The indicated capacities were not good (on the order of 2500 mAhr). I believe this was due to user error on my part with the DC6. I had the charge cutoff time set for 120 min (2hrs) thinking this was only for the period of the charging portion of the cycle. Based on another post, I increased the limit to its max (720 min) and am hoping the issue was merely my dumb mistake. I am also struggling to get the power supply budget set properly with my available eqmt. (I am using a car battery with a charger on it ... just trying to ensure the car battery does not discharge too far or get overcharged when running 4 DC6 chargers.)

I started all 4 charger/balancers this afternoon. (Start times were staggered.) I'll see what the status is tomorrow. Here is the setup.


Thank you for the comments and let me know if I should be doing something else. Otherwise, I think my next milestone will be in about 2 weeks when I have all the modules cycled.

 

Thanks for your comments also John. BTW, can you (or anyone else here) tell me the torque specs on those module terminal nuts? Based on the stud size, I would guestimate 20-30 in lbs (about 2 to 3 Nm for those in the metric world) but I would like to know the actual specification. Maybe Toyota never made that spec public since no one is supposed to be inside the pack?

 

Thanks all! I would have severely under-torqued without that spec.

Now it's a waiting game ... you folks who have been through this have a lot of patience. If I do this again, I am buying some more chargers.

 

Annealing certainly sounds like a good idea and I'm willing to be a guinea pig (or I should say my bus bar is willing). Worst-case, I destroy the copper connector plates and have to cut some new ones. (I was halfway considering this anyway.)

I am going to run this idea by some acquaintance(s) who work in the power industry ... seems there must be an analog there with the high-voltage connections found in substations and the like.

Thanks for all the torque specs! I read of nh70's problems in this area so I guess he/she learned them the hard way.