Help with error codes

I was driving my 2002 Prius yesterday (270k km) after returning from 3 weeks holiday and some dreaded warning lights appeared 10 minutes into my drive as I went over a speed hump.

Before going on holiday, I asked our house-sitter to drive the car every couple of days however I don't think she drove much because when I started the car the HV battery had only 1/4 charge which I've not seen before. The car started fine and very soon charged to 75% with everything appearing to be working normally until I went over the hump a little fast.

After getting home I got the following codes from Techstream.
P3000 (though the hybrid system light didn't appear)
P3006
P3017
C1259 (I read somewhere a regenerative system issue)

The traction battery voltages looked ok to me as I expected to see bigger differences between cells indicating a problem - though I appreciate there are other factors to assess to understand HV battery health. See attached image

The 12V auxiliary battery measures 11.48V so I will replace this and see what happens after the codes are cleared.

I had some unusual incidents almost two years ago when Toyota service advised the car was undriveable with a P3009 code but I suspect they may have been related to a 12v battery issue as when the codes were cleared (which the service shop failed to do) the error didn't come back and the car has been running fine since then. I've also taken advice from the forum and replaced the transaxle fluid and installed a new inverter water pump.

Given the car's age, irregular driving over the last few weeks and the heat we've been experiencing here, I'm not confident the fix will be as easy as it was last time!

Thanks in advance for any observations or insights.

 

Thanks for your analysis Steve, the graph is very helpful to visualise the voltage differences. So I understand the higher voltage of block 7 when the battery is loaded is indicative of the P3017 battery becomes weak flag which will also manifest in it dropping below other cells when accelerating.

I checked the freeze frame data for the P3006 (Battery levels unusually different) and Block 7 was lowest - 17.14V (0.03V below the next lowest). What I don't understand this was triggered when the SOC was 40% however with a SOC of 60% the voltage of Block 7 is 16.83V ? Seems the wrong way around...

It's been very hot here recently and the day the codes were recorded the temperature was about 35C / 95F, thus the inside battery temperature of around 50C. The fan was going full bore.

The link in your sig reminds me that a grid charger might help normalise / prolong the life of the battery.

I've understood from others here that an auxiliary battery measurement of 11.48v with ignition off is too low for reliable operation - then again I suspect it has been this low for some time.

Chap, thanks for putting the code reporting relationships into perspective. It can look a little scary at first!

How come the charge rate is expressed as a negative ie. -1.98 amps? I checked the P3000 INF code and yes it's 123! What does this mean? Thanks also for the reference to the repair manual - I don't have one but seem to remember there are ways to get access to this information online.

 

Today I took the car for a drive and noticed some abrupt changes to the state of charge as displayed on the MFD from 75% to 25% and then a gradual charge back to 75%, clearly the misbehaving block is creating havoc.

I noted in your linked post the reference to force charging as part of the process for reconditioning a battery together with grid charging. Somewhere else (can't find it now) you mentioned you've seen force charging normalise an out of range block, much like a grid charge process would. Doesn't happen often but has been noted. You said you need to charge to < 80%, wait 30m and check block voltages.

I thought I might give this a try - to replicate the HV overcharging routine the car sometimes initiates to rebalance a pack. Incidentally this occurred to my vehicle about 6 weeks ago on my way to work - the first time I'd noticed it. I was worried at the time that the ICE was not shutting down and the fan was going full bore in the back but the end of the day when I drove home everything was back to normal.

I spent a bit of time today with Techstream force charging to over 60%. The fan went to high speed and I noted battery temperature up around 55C but I'm not sure if I'm hastening the destruction of the battery with all the heat or if there are any other safety issues in pushing it beyond 80%.

Thanks for the suggestion - a lot easier to see what is going on with these values displayed.

 

The comment you made I referred to is here however on rereading it I realize I was probably clutching at straws thinking there might be a quick fix. On going back over the post and thread I understand there's a difference between a failed cell and a deteriorated module.

It was interesting to read this post again as it clarifies the process to find out where the gremlins are by charging and discharging, recording changes along the way.

Thanks for the heads up on the fan setting. Next time I'll fire it up at the beginning and wait for some cool weather - another heatwave coming... I'll report back with the results.

 

Here's the results of a test I did a few days ago. After seeing how effective a graph can be to visualise what's going on, I decided to plot the voltages from a forced charge above 80% as detailed in the link in Steve's first reply. I tried to go through the discharge process but the car complained and the SOC readings weren't making sense anyway. The sudden change of charge state as seen in the last reading seemed to happen for no reason. It would appear Block 7 is pretty unstable and is causing havoc - I guess this confirms it's toast and needs to be replaced. The question is - are the other blocks ok?



After reading the great stories by S Keith and Draco about their battery refurbishment experiences, I'm keen to tackle it also. My challenge will be to find a suitable donor cell or cells - there are so few Gen 1's here I'll be very lucky to find anything. I'm thinking I will also purchase a grid charger to assist with leveling the cells and modules - I can also use it to keep our Gen 2 in good shape.

 

Thanks for all your suggestions and help so far. As mentioned earlier, the big challenge has been finding modules to replace a failed one in block 7 and possibly others on the way out. Following a lot of fruitless searching locally and online and after considering options of importing a few modules from the US, I discovered a wrecker on the east coast with a 2002 sandwiched by a car on top with a battery for sale. Disregarding a lot of negative google feedback about the operator, I bought the battery for $170 and after some shipping delays it has finally arrived.

Before opening it up I noticed it had a Primearth EV Energy label instead of Panasonic EV as on the original. I checked online and read that Toyota's JV with Panasonic was renamed in 2010 so possibly a much younger pack? Taking off the cover it certainly looked clean with good seals and without electrolyte splatter I'd noticed on the inside surfaces of the original. I was even more surprised to see very little corrosion and no signs of electrolyte leaking at the terminals or any of the sticky gunk! Perhaps an improved terminal seal? Then a test of all the modules - surprise surprise - every one of them 7.59V!



So it looks like I've jagged a new-ish Gen 1 pack. A week ago, I received Hybrid Automotive's grid charger and I've been very keen to fire it up. I was thinking I'd be replacing modules in my original pack and running through the reconditioning process with the grid charger. Now it looks like all I need to do is some minimal cleaning of bus bars, reassembly and grid charging / reconditioning. I wonder if it would be necessary to load test modules or do other checks to minimise complications?

 

Yes, I discovered how flimsy the sensor tabs were when cleaning the bus bars on the original pack. While I only saw corrosion on one sensor tab, getting them out of the plastic housing was tricky with glue everywhere and plastic barbs holding the thin wire in place. I broke one and another was corroded so ended up crimping a couple of connectors on which I bought at an electronics shop.

I've noticed in the newer battery the plastic barbs are omitted so getting the sensor tabs out shouldn't be so difficult. Since I've already cleaned up the original pack's bus bars, I think I'll swap over the copper plates so the job should be a bit easier!

 

Draco - wanted to thank you for a post which I can't find just now about using the rejuvenation mode of your 12V charger on your battery. Reminded me that my charger does this too, so I did the 24 hour routine and found it significantly improved afterwards. What was a borderline battery (11.48V measured with a light on in the trunk), is now 12.7V after being disconnected for more than a day. I'll keep an eye on it but so far so good.

After charging the new HV battery with Hybrid Automotive's grid charger for around 18 hours, I fitted it back into the car today and started it up. Nice to see the lights gone and the car driving well - for a few minutes... the lights came back - yikes! So out with the laptop and Techstream to discover P3191 engine does not start.

Thanks to the many questions and answers here about this I learn it may be fuel / throttle body / spark plug related and notice the engine does start after resetting the code by disconnecting the battery. So maybe a symptom of sitting around for 6 weeks (and possibly in need of new plugs / throttle clean!) I did a bit of driving to see if the problem went away and it seems to have with that and some fresh fuel in the tank so planning a longer drive tomorrow.

When I'm comfortable the gremlins have been ironed out I'll do a discharge test as described by S Keith to see what shape the battery is in and report back.