Battery ecu

Usually high quality contact cleaner cleans that mess right up and if you open the case and look on the other side of the receptacle set the green board down on a light table which can just be an opaque piece of plastic with a fluorescent light underneath it and then you can look at all the traces on the green board running to the silver steel lugs that turn into the pins and the receptacle on the ECU unit I rarely see these eating through or anything like that and usually just cleaning them heals everything working is yours the red label or the black label ECU You just look at the label and do you see black or red and silver of course? The black is the latest one

 

Yep... Toyota Stealership is making a fortune selling brand new battery packs for the error codes that wee bit of corrosion makes. They also charge $800 for replacement ECU. Lol... So Dishonest.

The main concern with this is where those pins connect to the circuit board. So open it up and make sure there's no corrosion on that first pin thick enough to create micro-shorts with the pin next to it, which creates that familiar Prius symptom of your car's display screen suddenly going from 5-7 bars down to 1 bar. And because the source of this corrosion is coming from completely normal micro-seepage from the seals at the battery terminals, you're going to want to replace those wires, aka: "Wire, Frame, No.2" and clean the bus bars, etc.

 

It can still be driven generally with the red triangle on but what's the code limp mode probably not depending on codes present.

 

Yes it shouldn't be a big deal at all Make note of the color of the label on your battery ECU generally you want the black label The red one is the older but if it's working I guess it doesn't matter but if you wind up at a break or yard I always try to grab the black ones when I see them I'm sure he'll sort it out and short order.

 

So when it's all cleaned up and back in service and the bus bars and nuts are clean so on and so forth everything should run pretty much spot on unless you have some low or out of range modules in your battery pack but the ECU should be fine black or red I have a few reds in service here. I think the black is just the latest ECU in that series or maybe the last one made I don't know whichever.

 

This is a very common and very easy fix. Sometimes you can be lucky and the corrosion will be very light. Other times, it's so bad pins will actually rip out when you try to unplug it. Either buy a new ecu from Toyota for 800+ or get one from ebay for <100. Just make sure the seller provides good photos of the pins so you can verify they're clean. Heck, I have a dozen of them on the shelf. The black label ones are the earlier versions, the red label is the newer. Should be a 47092? if I remember correctly. Any of them will work, as I've had various ecus in various HV batteries in various cars. And yes, it would be best to get a new wire harness from Toyota, since there will be corrosion in the harness plug also. No sense doing a job only halfway. They're only 60 bucks new. I have a handful of those also.