$3000 Rav4EV project. BMS codes inside

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Jun 24, 2024
Hi everybody, I purchase this vehicle from a local that buys and sells cars via the auction. His ad stated he could not get the vehicle to charge. He provided me with a house charger and confirmed the vehicle would not charge. I did notice the charging lights in the rear would both illuminate for 10min and then both shut off showing charge was complete (from my research) although on the dash and in the data showed 0% charge. The vehicle does not drive, nor does it go into drive or reverse on the indicator. When attempting to get the vehicle in the ready mode I see "READY" will flash a couple of times and then go out. One thing I noticed when I towed the vehicle home is that the g48 coolant on the driver side was empty. I filled it with a gallon of coolant and still cannot see it in the reservoir. With a little research I inspected the vehicle speed sensor. When I pulled it I saw it was covered with brown rusty fluid, it also smelled damp and old like stagnant water (catastrophic yes)

With all that said Iam more interested in diagnosis the EXACT issue at hand. Despite the motor having coolant/rust inside of if it, if there is something ELSE preventing this vehicle form going into drive and charging. I would like to start there first. i downloaded the tesla software and made myself a cable to read the tesla side of the system. It pulled up a few codes, I took note and erased them. scanned again and kept coming up with BMS_F003 & BMS_f050. These seem a little bit like a generic type of code. looking for a way to diagnose these codes. Any help would be appreciated. Would also like information about how to repair the rotor/stator if need be. Is there any cure for one that has been rusted over? View attachment IMG_0721.jpgView attachment IMG_0723.jpgIMG_0726.jpgView attachment IMG_0748.jpgIMG_0754.jpegIMG_0755.jpg


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First of all, this RAV4EV needs
1. Replacement*)​
- rotor seals with Teflon seals installation​
- both hybrid/ceramic bearings​
- probably transmission bearings​
2. Checking​
- insulation resistance between the stator windings and the stator housing using a megohmmeter​
- condition of the rotor shaft surface​
- coolant entering the inverter​
3. To understand the essence and complexity of the problem, I recommend that you familiarize yourself with the video of this channel​

And most importantly, if you want to buy a vehicle, and don't want to buy a problem with the vehicle, then refuse to purchase...
IMO. It will be good if the repair of this vehicle costs no more than $7,000US and lasts less than 6 months...

*) Required spare parts

For example, BMS_f050 potential causes https://alflash.com.ua/2019/to_rav4ev/bms_f050ca.png

And Tesla haven't a test plan for this code :(
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The battery voltage is shown as 241 V - this means the average cell voltage is about 2.6 V, and most likely many bricks are well below that. This pack is likely irrecoverable/permanently damaged.

Was this vehicle flooded? The rust/grease seen on the speed sensor is more than typical for a failing coolant seal, and a flooded battery pack would yield some of the BMS errors you are getting. Pure speculation at this point, without dropping and opening the pack...

If I'm not mistaken, the G48 reservoir you show as empty is the one that feeds the battery loop. You've added a gallon of coolant and it's not satisfied . . . it may be pooling in the battery case :(

On the LDU, as long as you plan on doing a "coolant delete" mod, the condition of the rotor is fairly insignificant; the rusty crusty stuff can usually be cleaned up enough to work. The larger issue is stator insulation resistance, and corrosion over on the inverter side where the power electronics live. Much time spent soaked in coolant and both of those become scrap. The key is to get it apart ASAP.

If it were me, I think I might disconnect the coolant lines to the battery (underneath) and pull a mild vacuum on the battery cooling loop to establish that it's still water-tight.

There's a scrapyard in Wisconsin advertising a HV pack for under $1k. Shipping to Calif. would come high, perhaps almost doubling that cost. And I doubt that they can advise on its condition, so . . . an expensive gamble. Swapping out the 900 lb. battery requires a level surface (ie not a sloped driveway), patience, two to four floor jacks, and lots of 4x4s for cribbing and load spreaders. But the cost otherwise is low enough for DIY.


My gut feeling is that, faced with both a battery replacement and and LDU replacement, this may be hard to part out to recover your $3k.


If you decide to part out this car, I'm looking for a cheap intact battery case (I do not care about the condition of the modules/cells, though it would be desirable for them to be present and unmolested). Emphasis on cheap. West Coast or similar (SoCal would be a good road trip for me).
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Well thank you everybody for your insight. I made some progress today and decided to pull the HV battery. I’m not sure if this is good news or bad news but, it looks as if the vehicle was in an accident at some point. The panel where the desiccant bag goes was not sealed and looked as if it was ripped passed the bolts that hold it down. The warranty stickers were still in tact. The plate around the hv battery fuse was also cracked. I’ll be posting pictures later. Next will be opening the housing and looking for water intrusion. Up until this point it doesn’t seem like there was any water ingress. Let’s hope. Hopping to see a bad contactor or 2.

Also, I have checked my charger port for the proper resistance across the pins based on an image I found on this sight. Everything checks out.
You might watch this YT vid of opening a Model S pack, to get a feel for the challenge on the RAV4 EV pack.

I bought the Fein bits, because I own an original FMM250Q MultiMaster, and I plan to do this job one day.

Fein_Z-bend_blades_01b.png Fein_Z-bend_blades_02b.png Fein_Z-bend_blades_04b.png

You can use a putty knife and hammer, heat gun, etc., but be very careful to not insert the blade too far. There are at least two places where there are delicate things right next to the seam.

James Klafehn has at least six vids on pack disassembly. This one is representative:

Thanks for that tip. I bought an attachment for my multi tool and it cut the sealant like butter. Unfortunately when I got the lid off I found the reason for the BMS_F050 code. No communication due to a burned up board I assume. The entire bottom of the case is filled with blue coolant. I suppose next would be to take the modules out and check them all. A few test I have done so far have showed 39v on a couple of different modules (not sure if I’m performing the test correctly though). I show just under 200 volts on the entire pack. Thinking about possibly replacing maybe 2 or 3 bad modules. Anything more than that I’m not willing to make this a money pit. IF I got this to charge and the battery’s were OK I would still need to tackle the coolant intrusion in the motor and bearing replacement.


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I agree that that looks as if there was a severe jolt (accident, etc) and one of the plastic internal coolant lines broke. Ugly.

AFAIK, you can't buy modules for these, unless you find someone in a similar situation with a half-destroyed pack. The Model S modules will not fit, they are a different form factor.

I don't know if you can swap a BMB into the pack (the burned-up board). IIRC on the Model S they have addresses that are unique, and the master BMB may not play well with a swapped-in one. Think "have to code the module", only there's no software available to us to do that, and Toyota doesn't have it either. The Model S folks have more info on this, if you decide to research it.

You can very likely sell the not-terrible modules; lots of people are looking for both stationary solar storage and raw packs for DIY EV conversion projects. They have a market. Problem is, everybody wants matched modules, and you may not have enough to obtain the pack voltage their project requires. But 50v (nominial) modules work sorta-OK on 48v solar systems, so somebody is going to be interested in them.

If you didn't have to also deal with a bad LDU, this would still be a good candidate to obtain a used pack and rehab.

If you have the time to drop, pull apart, clean, dry, re-bearing, re-seal, and "coolant delete" the rotor to a dry setup, and if the stator has sufficient remaining isolation resistance and the inverter side is dry (or dry enough) . . . it could still be put back to operable, with a different traction battery entirely. But the market for these is around $7-12k, so you'd have to want to keep it & drive it, not flip it for a profit, as the margin is probably too low.
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Damn, these were the packs I was looking at. I’m about 10miles from the seller. Haven’t done enough research yet though. It says 18650’s so I was hopeful.


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Damn, these were the packs I was looking at. I’m about 10miles from the seller. Haven’t done enough research yet though. It says 18650’s so I was hopeful.

The seller indicates they are selling RAV4 EV modules, as both sizes/formats are listed ( https://jag35.com/products/toyota-rav4-battery-modules-by-tesla ) . But the hassle of swapping in unknown modules into a case that already has damage is probably a far greater cost and effort than just swapping in an entire battery pack from a salvage yard.

Your best bet is probably parting this vehicle out. As Al notes, there is a market for the used Tesla modules. In the RAV4 EV community, there is a small but regular market for a working on-board charger, coolant heater, coolant pumps, nav head unit, etc. Non-EV specific parts like body panels and air bags should also have a decent market.
The top layer of modules in your pack is probably OK. However, there is little hope of doing anything useful with the ones soaking in coolant. Also, replacing that bottom layer with modules from different packs is unlikely to be successful long term. Tesla packs have to be capacity matched in each cell group. You are unlikely to be able to find modules that have the same capacity and you would have to charge everything to exactly the same voltage before you close up the pack to even attempt to use the car. If you want to make your car drivable again, you have to find a complete pack and part out your pack.