Timeline/options for P3006

Our 2002 just ticked over 200,000 miles and now has the dreaded triangle and DTC P3006 (uneven SOC in HV battery). It putters around, but the MFD is lit up with alarming icons. I cleared the code once, drove two miles, and turned the car off. On the way back home it came back on. We have owned it a few years, the previous owner was a mechanic who bought it at auction, replaced some of the cells and flipped it.

I can access the block voltages, but they don't point to any obvious culprit. I'm also using EngineLink with a PID list adapted from Gen 2.. so the formulas might not be appropriate. I checked both running and engine off, and both times Block 6 was slightly lower.. on the order of .02v. From what I understand, it takes .3v difference to throw the code. Of course the only real test would be under load.. so I don't know what to make of this. But, am I correct in believing that P3006 specifies a problem in block 6, or is that a general code?

The DeltaSOC is 51%. Again, I can't vouch for the math, but this seems pretty high.

There are a lot of great resources here on replacing modules, if/when it comes to that. I'm curious what else I should try before taking the plunge, and how urgent the situation is. Our repair shop is hybrid-friendly (and has a loaner car) so I could just hand it over. But I also don't want to start throwing money at it for something within my abilities. I'm in an electrical technology program, so this actually sounds like a fun project.

-This car is our only one, and we take a couple short (3-10 miles) trips a day. I'm wondering how long we can limp along while I diagnose and maybe order cells. I assume when the triangle is lit up, the HV battery is used to start the engine but is not charged or used to run the MG? So regardless of any other damage it could do, the SOC will eventually drop dangerously low.. unless it gets sufficiently recharged when I clear the code.

-What sort of damage might we do to the car by driving it in this condition?

-It seems like the other potential culprits could be harness connections or busbar. Any other easy things to try before I pull the battery and load test the cells?

Thanks for any feedback,

 

I'm handing it over to the professionals for diagnosis. They will be able to pin down which cells are bad, check any codes I can't see, and rule out other components. The biggest reason is that they have a loaner program. The HV is getting lower (limped it to school and back today) and it will end up needing a tow if I push my luck. If I do replace some of the cells, hopefully I can get them delivered before they hand the car back.

Plan A is still to do the repair myself.. the shop would only do a full battery replacement. They have been great about helping me do repairs myself.

 

Thanks DRACO,

Added P3002 and P1636 to the list. Since those are ECU/communication codes I checked the 12v. It's at 12.25v, I'm charging it tonight.

The SOC battery icon fluctuates up and down pretty rapidly. It's been keeping the battery above 50%, and I can confirm the current flow with enginelink, but I hate driving it like this. Hopefully I can drop it at the shop tomorrow afternoon.

 

So.. the 12v was bad, and replaced free under warranty. But, it had no effect of the HV situation.

I'm just going to do it myself. It doesn't make sense to pay a shop for diagnosis I'm going to do anyway when I replace the modules. I've been watching the voltages, I suspect 5, 6, and 10 are weak. I ordered 4 ebay modules from a seller with great ratings and a warranty. I also have a charger/balancer on the way. This will be a fun project for Saturday, and it's real easy to cure the codes on the fly with enginelink until then..

 

I bought the Tenergy TB6-B 50W Balancing Charger.

Underestimating projects is my specialty, but I realize just charging and balancing the modules with a 50w charger would take all day even with minimum down time. I'll probably get right to it friday night removing the battery and initial testing. Saturday will be balancing, charging and reassembly. I have Sunday morning too, if needed.

As far as cost.. the shop will not replace modules. They would only do a battery replacement. I didn't get a quote on that, but I'd be very surprised if it was less than $1,500. This car is in good shape for a 14yo, 200k vehicle, but it's certainly to the point where I hesitate to put a lot of money into it. With shipping the modules were around $200 I think. It will probably be another $150 for PPE, charger, and misc but those will be useful to have.

I'm in an Electrical Technology program, pursuing a career as an electrician (primarily solar). But right now I'm a bike mechanic. It would take a lot longer to earn the money than to do it myself and broaden my experience. Also.. great excuse to buy HV gloves with my student discount, this won't be the last battery bank I work on. As Keith said, it might not even be the last time I work on this one unless I get the balancing right

Thanks for the feedback, folks

 

Battery is out, and module 27 is clearly bad. The rest are similar, but have a significant sag towards the middle of the pack. Variation (besides 27) is .08 volts between highest and lowest.
1 8.21v
2 8.19
3 8.19
4 8.17
5 8.18
6 8.16
7 8.15
8 8.15
9 8.15
10 8.15
11 8.14
12 8.14
13 8.13
14 8.14
15 8.14
16 8.13
17 8.13
18 8.13
19 8.13
20 8.13
21 8.13
22 8.13
23 8.13
24 8.13
25 8.13
26 8.13
27 6.79
28 8.13
29 8.14
30 8.14
31 8.15
32 8.15
33 8.15
34 8.16
35 8.16
36 8.17
37 8.18
38 8.20

But, the modules might not come in until Monday. UPS claims the seller didn't drop them off until yesterday.

 

So, I got the car rolling again. The modules did finally come in and I put the car back together after work one night. Because they didn't come in when expected, I had even less time than planned and didn't do any balancing or charging. I charged up a couple of the replacement modules, picked my favorite and then used a light to draw it down until the voltage was close to the others both loaded and un-loaded. At some point I will get back in there and balance them properly, but the car is running great now. No codes, restored acceleration, etc.

Thanks for the help folks, I should retitle the thread "Sort of fixing P3006, for now at least".