New OEM battery questions

Installing a new OEM battery in our 2007. The old one wasn't throwing codes but the voltage kept collapsing without reason, and at ~17 years old, that seemed like long enough for an original pack.

After returning the first new pack (it somehow shipped with all the plastic on the anterior side broken) and picking up a second pack everything has been transferred over and tomorrow it goes back into the car for a test. There were a couple of things which didn't seem quite right though, and a few other questions arose:

1. The orange plug which goes into the CPU, which came already mounted on the pack, was upside down. That is, it was rotated 180 degrees from the way it plugs into the ECU. I tried rotating it in both directions and one was way to tight (on the wires) and the other was merely very tight. Once it was plugged in the clip an inch or two back down the cable plugged in OK. I would have thought that the plug would have been oriented correctly to just plug into the ECU without needing more than a couple of degrees rotation one way or the other, definitely not the ~180 it actually took.

2. The cable attached to the socket for the safety switch is bolted onto the posterior side of the pack, and the skinny part of those wires are clamped all the way into the dual cable holder which hides under the black plastic. There is a latch on the edge of the black plastic which is supposed to hold it down, but the cable seems to be too fat and it won't latch, so that black section does not look fully closed. For whatever its worth, the same section on the old battery wasn't latched either. Is this a problem?

3. There were 4 nuts which came with the two foam pads. I used those to attach the cables to the posts in the row with the modules. They appeared to have received a very thin coat of some light green material on the contact surface. This is new, out of the bag. Are they supposed to be like that?

4. For the core return, do they require that all the cables that shipped with the new pack be detached from the old one? The safety switch cable is off, of course (no other way to get it out the metal mount), but the two cables on the anterior side are still attached on the old battery. That is, there are 3 cables on the anterior side, instead of the one it ships with.

5. The cable that runs on the anterior side of the pack and ends with a black color at the junction bar, again, on the anterior side, passes through a white round device which has a small plug going to it on the side facing the ECU. Is that a DC current clamp?

Thanks.

 

I looked carefully at the pins on both the orange plug and the corresponding socket on the ECU and all the metal was nice and shiny. Can the ECU be corroded inside with nothing visible on the outside? There wasn't corrosion anywhere in the assembly which is transferred over.

Speaking of corrosion...

The back metal panel, the one where the tube from the top of the pack comes out, has bolts welded onto the inside. Every one of those was rusty. However, none of the surrounding metal was.

There was also some really odd corrosion on the metal pieces which go on each end of the pack, that bolt it to the car. This was mostly on the top but a little on the bottom. It looked a little crystalline but mostly like a big rat had puked on that surface and it had dried. Nothing like that inside the battery case at all. I scrubbed this gunk off with a toothbrush and water and it revealed some patches of rust underneath, where whatever this was had eaten through the paint.

There was no sign of electrolyte in the rubber ventilation tubes on top of the pack, nor in the little barbed tubes to which they attach.

There was just a little bit of blue flake material where the safety switch was bolted onto two modules, inside the little black clam shell contraption. I didn't pull off the rest of the plastic on the old one to check. I didn't see any corrosion on the connections at the 3 little doors in the black plastic on the anterior side of the pack though.

 

OK, I will pull the ECU and look inside. The process would be: unplug both connectors, unscrew the nut which is holding down the big aluminum shield (that comes in with the black cable from the anterior side of the pack), unhook the clip on the cable for the orange plug, lift out the ECU? Or are there other fasteners holding it in?

If that connector is all shiny and clean leave it alone(?)
If a little corrosion or dirt on the pins on the inside hit it with CRC contact cleaner.
If the damage has spread to the board find a replacement ECU.

Unclear to me how one would obtain a clean ECU other than buying a new one from Toyota. The state of the used ones on Ebay and such is never more specific than "working".

 

Not even close. List is $1126.25.

https://parts.longotoyota.com/oem-parts/toyota-drive-motor-battery-pack-control-module-8989047092

Stupid car ECUs are proliferating like mice and they are a profit center at repair time. They are just little computers and don't actually cost that much to make or for the manufacturer to buy. But if one blows up and a used one cannot be found the manufacturer will exploit the monopoly they have on the part to extort a ridiculous sum from the owner of the car.

 

Well, I tried to get that little computer apart but the screw was stripping regardless of which Philips head was used, and I couldn't get enough of a grip on the sides of a screw with any of my pliers to turn it.

On the other hand, it was a very sunny day and I noticed that if the gap between the orange socket and the case, the pupil of my eye, and the sun, were all placed in exactly the same plane all the vertical connectors for the orange socket inside were visible. Or at least about 1 mm of them just above the circuit board was. They were all shiny gold and clean, and the end ones looked just like the center ones. Also the case of this ECU was spotless, no dirt or corrosion at all. So I figured this device was probably still good and completed reassembling the car. Drove it a couple of miles with the new battery and all seems fine.

If it still keeps having the voltage dropouts I will find another ECU somewhere and replace it. I'm not convinced that those dropouts are always the ECU. Our old Honda Civic Hybrid would do similar wild SOC swings when the battery was going out (which was all too frequently, they used a crappy battery technology), and there was nothing wrong with that car's electronics.

 

Could have been. I didn't notice the "dot" those (supposedly) usually have, but the screw was not very big, so maybe they omit that on the smaller fasteners.