Hello all, I'm grateful for this forum's existence and have eyed it now and then for DIY info but only last month got a Prius. I bought it with a bad battery. When I test drove it it had no power and didn't want to go very fast (limp mode?) but signs seemed to agree with the battery being the issue and it did drive so I bought it. Sure enough, 3 cells were bad, 3 more were weak, so they've been replaced and the pack has been reconditioned. My Prius now won't start and simply displays "Problem" on the dash. Previously I had to move it with just the 12V and it gave a message about not being able to go into Park and to apply emergency brake and park on a flat surface. I "think" that is sorted once i charged the battery and turned it on and off again but I'm not 100%. There is an errant plug that eludes me as to where it belongs near the battery, a three-pronged white plug which connects to the control box next to the battery (ECU/BMS?). Previously I had missed the plug which connects to the orange fuse disconnect(does the orientation of this plug matter blue/black?) but now it's just that 3-prong white one. Any help will be showered with praise or cash if that's your thing. Many thanks in advance for all you kind people.
There are three connectors that attach to the electronics section of the HV battery. The largest one goes to the ecu. The medium one (3 wires) is for control power to the relays. The smallest one (2 wires) is for the safety interlock switch.
Welcome! GREAT! Better to get all the life out of the remaining 22 modules than simply replace them all, IMO. Problem can mean a number of things, best to get the codes read and often a generic scanner will not get the information needed. ALL plugs on a Prius matter, both to actually being connected and to orientation. Having worked quite alot on Prii but not extensively as for example, the folks at Luscious Garage, I doubt it is possible to get a connector re-connected "wrong". All the connectors on these cars are what we call "indexed", so as to make it *nearly* impossible to mis-connect them; be it to the wrong place, backwards or otherwise incorrectly. I would start by charging the 12v, removing the HV safety plug and going over EVERY electrical connection between the HV pack and the car to ensure all connections are correct, seated and secure.
Thanks all for your replies. I suppose a picture would be helpful It is on the top left of the large white connector on the HV ECU, with yellow brown and black wires. It extends from there to the three prong shown in the foreground. Any thoughts?
You gotta balance your cells before they go back into the car or the bms will trigger codes. You can balance your cells by discharging each cell down to 40 percent of charge and recharge all in parallel to the same voltage using a diode on a wall work plug slowly over a week they will settle at the same voltage. Posted via the PriusChat mobile app.
Here is the pic, it is shown on the top left of the large white connector on the HV ECU, with yellow, brown, and black wires. It extends from there to the three prong shown in the foreground. Any thoughts? 20181113 161419 — Postimage.org The cells are perfectly balanced fwiw. They were connected in a parallel with leads at opposing ends to balance current between cells, cycled, then sat for for a week.
Yeah, you need to plug that in. It is right in the area where the plug is located. It connects to the white current sensor. Kind of on the edge of it. My screwdriver is pointing to it in the attached photo. Look a little more carefully and you will find it.
