Wife or daughter somehow drained the 12v aux battery one day so we jump started it, several days later dead again. A charger was put on the battery for a couple of hours while in the car (out of ignorance). Ran fine for a few days then dead again now with the "check hybrid system" and "check vsc system" warnings and battery cooling fan running. Found this forum, read about the optima yellow top replacement so I did that. It starts now with no problems, warnings still there and battery fan still running. Now the engine also dies sometimes while driving. Read more on this forum, pulled the hybrid battery and there was tons of corrosion on the bus bars. Pulled them off cleaned everything very well with vinegar and then baking soda, reassembled and put Ilsco De-ox gel on every connection (front and rear of bus bars and the little crimped connectors on the front side, then covered the nuts as well...wondering if I created a situation similar to the oxidation since the de-ox does not conduct, but all connections tight. It is covered in anti ox gel. my daughter backed into another car and mis-aligned the trunk lid slightly so there is a very small leak in the trunk when it rains hard enough and it is 100% humidity half the year in Pensacola, FL). Aux battery was unhooked with the terminals connected together while I cleaned the hybrid battery. Reinstalled everything and same warnings. The codes pulled at auto parts store are
C1241
C1256
C1259
C1310
P0480
P3021

The car has 122,652 miles and was bought new in Indio, California in 11/06. It has been a wonderful trouble free car until now. I thought it was a simple clean connections job or I would have called toyota about it. The dealer here in Florida is shady. I have noticed some extremely wise folks on this forum, any help would be greatly appreciated. Thank you in advance.

Jason

 

C1241 is a low voltage (12V) to the brake controller system skid control ECU

C1256 is the brake Accumulator Low Pressure but is common if C1241 is thrown. That issue needs to be taken care before this can be diagnosed.

C1259 is the HV System Regenerative Malfunction and that code can be thrown by C1241 also but can also be thrown if you turned on the ignition with the service plug pulled on the traction battery.

C1310 is the HV System Regenerative Malfunction code and again is thrown when the Skid Control ECU is sending a signal and the Hybrid Control ECU has a low voltage. This is also thrown if you turned on the ignition switch with the traction battery service plug pulled.

P3021 is the "Battery Block 11 Becomes Weak" code and will more than likely be the issue causing your problem. Are you SURE you cleaned and torqued everything correctly when you assembled the HV battery? Did you check the voltages of the 17 battery blocks and see if one of them was lower or higher than the others? By the way, this code is thrown for a .3 volt difference.

That battery consists of 34 battery modules combined into 17 blocks (2 modules per block) with (6) 1.2 volt cells in series. ANY cell in that module or block (12 of them) could have a loose or bad connection (or be a bad cell) and that code will be thrown.

You need access to a scanner capable of doing a better check on codes and able to do some bi-directional scanning (IE Techstream or good pro scanner) at this point to see if the battery bank or the smart controller on the battery bank is the problem.

I have a sneaky idea that your "P0480" code is really a P0A1F-123 code that their scanner is not capable of reading. That can also be thrown by a low voltage on the aux battery (12V) but there are other items to check as well (fuse IGCT number 2 for example) that can cause this as well.

One thing is bothering me though, per your post above, "Aux battery was unhooked with the terminals connected together while I cleaned the hybrid battery". Did you actually hook the + and - battery cable together when you cleaned the hybrid battery?

Personal opinion, clear all of the codes and make SURE the 12V battery has a good charge. Drive the car and see what codes it throws and then let us know what codes are present. Most of the codes you have are from the 12V battery being run down before.

 

Thank you so much for your reply. Yes, I did try to start the car not realizing the service plug was not pushed all the way down. When I unhooked the 12 volt battery to pull the hybrid battery I did hook the 12v cables together. (To drain residual power from that system...something I read to do on toyota nation I believe. Again ignorance....) I did check voltage of all 34 modules, one module did read 6.8V. I didn't want to try anything other than cleaning that monster and reinstalling in hopes it would recharge from the car. I only have a schumacher ssc-1000a charger that only does 12v that I used to charge the AGM battery. Everything is clean and tight. I was worried the de-ox may do the same as the corrosion as far as resistance after it didn't work...apparently not that simple. I will do as advised above and get back as soon as I can. Any opinion upon ordering obdII to usb cable that comes with cd software for laptop from internet vs. larger expense of taking to a shop to have diagnostics test done after clearing codes and driving? One last stupid question, can I clear the codes myself without a scan tool? I don't want to make any further ignorant moves.

Thank you sir.

 

Never heard of the terminal joining thing. Would never consider doing it without the manufacturer telling me it was okay AND explaining WHY it was okay.

Disconnecting the 12V clears codes; however, conditions still present will cause the code to return immediately. That 6.8V will likely immediately trigger a code.

6.8V is a dead module. Period. You have a failed pack.

 

I have no experience with the USB cable with software downloaded from the net. I use two different Snap-on scanners that work with pretty much any car I work on. Generally disconnecting the 12V battery will clear the codes but there are some that it will not clear.

What was the voltage on the other modules in the pack? Were they all balanced? You might get by with replacing that one pack if you can find one that would be balanced with the other battery modules.

 

It took me forever...but i got it. 11 is bad apparently. Can anyone tell if there are any other problems or not from this? I have plenty more system data if needed.

 

I removed the pdf's and posted jpg's instead

 

Those are codes typically generated from failures on other ECUs due to the traction battery being inoperative. If they weren't present before the battery issues, they should go away once the battery is fixed.

 

I am going to order a couple of modules off ebay, should I replace both modules in bank 11 or just the one that tests weak? Also going to order a Prolong Battery Reconditioning Package. Any suggestions from anyone that has experience with that charger or strongly suggest a different one, or certain options I should get on anything? I'd like to make the best decision the first time I don't have the money to spend twice. S Keith, there were no dash lights, warnings or known issues before the battery problem, so, yes, hopefully everything else will clear up when the traction battery is fixed. Thanks for the replies and sharing of experience.

Jason

p.s.- just for kicks, now that I know I can post pics, here is the corrosion I discovered when i first removed the battery...

 

You plan is very sound. The issue is going to be the eBay modules. They are VERY hit and miss. Based on my take on other's posted results in other forums, it's best to order a couple from different sellers as some people sell pure garbage.

Also, try to avoid folks who will only guarantee voltage. Voltage is only the FIRST criteria to be met, and the easiest. I have a module that maintains good voltage for many months... but... it only has a capacity of 2700mAh because one of the six cells has significantly lower capacity than the others.

Are you in a coastal area? The black is indicative of salt-laden air.

I think that corrosion is the worst I have seen. You should consider purchasing new nuts rather than futzing about trying to clean those:

https://www.belmetric.com/nspin5ylw-...tn1&cPath=3_49

If you're looking for a quick way to clean the bus bars, muriatic (hydrochloric) acid will get all the yuck off in about 30 seconds. That acid is used to lower pool pH and can be had for about $8/gallon (my local Ace hardware, any pool supply store, etc.). simply put all your bus bars inside a small glass container (I literally use a drinking glass) fill with just enough acid to cover them by about 0.25", agitate (swirl) gently for 30 seconds, fill with tap water to dilute and dump repeatedly. This create some acrid vapors from initial pour to the end, but a gentle breeze is enough to keep them dispersed. Once rinsed and dried, a very quick, light scuffing with green/maroon scotchbrite will have them looking good in a few seconds. Your total touch time should be less than 20 minutes.

The Hybrid Automotive prolong reconditioning system is a GREAT way to recondition an entire battery at the pack level. Multiple discharge cycles can be nearly as effective as reconditioning at the module level. I have direct experience with both. I encourage you to take the time to do it as prescribed on their website. Full disclosure, I am an Authorized Installer for HA in the Phoenix area which makes me eligible to purchase at a small discount. I receive no compensation of any kind from HA. I support them because it's the best option out there and the best total value. They have also been at it the longest and use the best body of research data in their approach.

Best to start a google sheet and document the voltage of all 34 modules. Any significant outliers should be replaced.

Steve