2001 HV Battery ECU & possibly battery pack

DTC P3115 points to a traction battery current sensor malfunction. I no longer have my Classic repair manuals, having sold my 2001 last year. If you want to invest $15 in techinfo.toyota.com you can access the repair manual for your model year and look up the troubleshooting associated with that DTC.

I am not aware of aftermarket alternatives for the Classic battery including a plug-in option.

Good luck.

 

Yes, DTC P3006 means that at least one module pair is producing a different voltage level compared to the other module pairs. My 2001 produced that DTC when its traction battery failed under warranty.

It is possible that P3006 might be an artifact. The way to prove this would be to open up the battery case and measure the voltage produced by each of the 38 modules.

If you find a module producing less voltage than the others, that is strong evidence that module is dead. However this is not a DIY activity unless you are comfortable dealing with high voltages and currents that have the potential to kill.

 

I'm facing the replacement of my '02 Prius's HV battery as well. My repair rep says that I have leaking cells and that Toyota doesn't replace cells anymore; they don't carry the parts. The Toyota Customer Relations Department claims they never were able to replace the cells although my repair rep confirmed that the Gen1 battery had replaceable cells.

Does anyone have more detail on this?

 

All versions of the Prius after the Original (NHW10) have modular batteries, made up of 38 (Classic)/28 (hatchback) 7.2V modules for a total of 273.6V/201.6V.

For best performance and life, the cells in a battery should be closely matched. Over time, the cells that are weakest tend to get weaker and eventually the cells diverge too far with the risk of developing an internal short. This is why the Prius does not permit too much divergence in cell voltage (the P3006 code) - this seems to be the most common problem for old batteries.

Replacing modules is possible but I don't think it's a particularly good idea, because it will be very hard to match them to the aged modules in the battery. Brand new modules will always start to damage those around them. This may be why Toyota only sells complete batteries.

You can still buy a whole new 38-module battery but it's expensive. Some people have built replacement Classic batteries out of two hatchback batteries (to get enough modules) from crashed cars, but again I think you're going to get module mismatch problems.

There was a battery resealing special service campaign that should have been done on your car - there should be a sticker on the driver's doorsill to say that this was done. I'm not sure if Toyota would honour that programme at this stage, though.

 

Mike,

I found out about that Special Service Campaign while my car was in the shop. I asked the service rep about it based on my VIN number but he said it didn't apply to my vehicle. I get it back today and will be checking myself; I don't think the service rep put too much effort into it.

I've requested my old battery back so I could take a look at it. Anybody got sources who would be interested in purchasing an old battery with a few bad cells?

 

Yes, the traction battery replacement is not usually considered to be a DIY activity unless you know how to deal with dangerous voltages/currents and have access to the repair manual info. Should you care to research the battery replacement process, I suggest you download the relevant repair manual sections at techinfo.toyota.com

The module replacement process requires disassembly of the battery, so this is more involved than the process of swapping out battery assemblies.

If you buy a salvage battery it may or may not come with the traction battery ECU and the system main relays. If not then you will have to transfer those components from the original to the replacement battery case.