2008 base model Prius. I'm troubleshooting a diagnostic code P0A85; "Hybrid Battery Pack Cooling Fan 1. The troubleshooting procedures include checking the various wire harnesses for opens & shorts. A couple of the steps involve checking connector pins on the Battery ECU Connector. I hope it doesn't take me all the way to those steps, but if it does I need to know where the ECU is actually located so I can access the connector. Any help would be appreciated. Photos? Thanks again.
It's inside the front end of the battery case so when you whip the cover off the top of it take all the stuff out of the trunk the plastic and whatnot and you're staring at the battery from the open hatch looking down at the battery all the way to the left is the front end of the battery you see the orange wires coming out of the front of the battery which is on the driver side or the left that's where your battery ECU is there's a few 10 mm screws that you're going to undo and that front end piece will lift up and away and you'll be looking down at the relays and the battery ECU the ground straps and penetrating orange wires but before you even get started you need to remove the safety plug which is on the same side of the battery is we're discussing up towards the rear of the car right next to the plastic box with the magenta writing on it so something about some kind of megahertz it's part of the alarm system there's an orange safety plug there you'll pull down and withdraw the handle at 9:00 and then pull the hole plug out and just lay it down now you're good. You can undo the front end of the battery with that up there's a couple 10 mm screws you can undo and then you can lift the battery ECU up get it to orange plug that's the one you're interested in remove the plug look in your plug and look in the receptacle on the box You see the corrosion in the corner now take apart that whole ECU see the corrosion on the back on the pins as they bend 90 into the board and a soldered All that green needs to be cleaned up. If you want to carry it a step further you can lay the circuit board that you're holding and cleaning You can clean the whole circuit board with circuit board type cleaner a Stoddard solution whatever. You can lay the circuit board on a light table and with a magnifying glass a powerful one you can look at all the ways on the board and if you see any breaks or any funny business maybe not to reuse.
Before you go digging in too deep, just inspect the fan (behind the trunk trim panel on passenger side), the fan relay (mounted to the plastic air duct attached to passenger side of fan) and the electrical plug connector several inches back from the fan toward the back of the car (this connector frequently gets significant corrosion)
Thanks for the details, Timbuk2, on locating the Battery ECU and how to "approach" it. Thankfully, just like TMR-JWAP suspected, there were two wires corroded at the connector mounted just above the fan. They were so corroded, and I don't have the replacement pins nor the tool to replace the pins, etc. so I snipped them off and jumped each of them. I put "spade" type (a male & female combination) connectors on the wires, wrapped each end with electrical tape to insulate them and that extinguished the Red Triangle w/ Exclamation symbol on my dashboard. I also removed the fan and cleaned the fan vanes. I also cleared the P085A code & re-ran the diagnostic and the P0A85 error code did not reoccur. Thanks again for your generous sharing of your knowledge guys.
High voltage wiring is 60 volts and up. It's orange for a reason. You need gloves and training for the safety procedures. You also need a spotter to know that you're working on the system at that time. I don't recommend you go digging around in there
You should take some zip tape and pancake that white connector with the zip tape so that you make a complete seal around that white connector so that if any water falls from the trunk seal or any of the cracked sealant that's used at metal assembly time at the factory leaks and goes on to that connection at least it's going to fall on sealed zip tape and it will never leak that way there this doesn't happen again sometimes you can take that white plug off of its mount push it in far enough to tape it literally to the back side of the metal body rear quarter panel that also keeps it out of water and moisture's way I've done both with all three of mine and have not seen any issues with the system since luckily I've been able to catch mine clean them and still use the plug but if not jumpering over the plug is the way to go.
