I'll check that out. Is it even worth cleaning the corrosion? I'd only be worried about somehow messing up something that works fine anyway...
I would say, if it looks ok, put it back together and sleep soundly. On the other hand, if it is on its way to looking like the top one here, I would just replace the forward wiring harness on the battery (buy a spanking new one from Toyota, it's not much) and see how clean you can get the terminals of the ECU (because replacing that is more money). If the answer to "how clean you can get them" is "not very", then I'd seriously consider shopping around for an ECU also. In trying to "clean" the terminals, avoid any flavor of contact cleaner that leaves a lubricant or other residue; those connections are high voltage and it will follow stuff around.
This was some interesting reading.....but i'm totally missing the connection between the original problem and cleaning the HV battery...what am I missing?
There was no direct connection. The OP had a trouble code pertaining to a relay located in the underhood fusebox. Then there was a post that mentioned the main relays inside the battery case, though they are not what the code was about. So the OP ended up digging into the battery, arguably unnecessarily but what's done is done. I then went with the flow and suggested as long as you're in there now anyway, might as well check those sense-connector pins before buttoning it back up, because that is a known thing, even if unrelated to the topic of the thread.
That's basically how it went. I don't regret taking the battery out - I wanted to check on the corrosion and also just know that I could do it before the likely event of having to purchase a replacement in the future. The connector pins seemed fine, so it looks like in the end it really was just a slightly loose positive terminal connection on the 12v. My best guess is that the error code, which came and went quickly, is unrelated. They just both happened in proximity of each other. I really want to thank everyone for help and advice - even though it was a bit of a wild goose chase I learned a lot and have some more confidence in taking care of my car.
Hey sir, great post! I just bought a 07 Prius with 118k miles and it is having literally the same exact problems. I know this is a old post but did the loose terminal fix your problem? QUOTE="nofrillscustard, post: 3070671, member: 186638"]That's basically how it went. I don't regret taking the battery out - I wanted to check on the corrosion and also just know that I could do it before the likely event of having to purchase a replacement in the future. The connector pins seemed fine, so it looks like in the end it really was just a slightly loose positive terminal connection on the 12v. My best guess is that the error code, which came and went quickly, is unrelated. They just both happened in proximity of each other. I really want to thank everyone for help and advice - even though it was a bit of a wild goose chase I learned a lot and have some more confidence in taking care of my car.[/QUOTE]