Bleed brakes without traction battery?

I think you can bleed the brakes with the HV battery in or out of the car with the orange plug out or whatever I'm not sure what Toyota software is going to have to say about that but it should be interesting I personally haven't done it that I remember anyway usually my traction battery is in the generation 3 when I'm bleeding I don't even have a jump box or maintainer on the 12 volt when I bleed It doesn't take me long enough for the 12 volt to go down when I'm bleeding the brakes on either of the two models I have so we don't generally do that either but if your battery's questionable the 12 volt you need to put the charger on it especially if you're going to be sitting there and staring at a lot of screens and studying long then hook up to the battery tender everything in the brakes I believe is all 12 volt activity.

 

How about trying this?

 

That's a brake fluid replacement video (and props to the maker for saying so, How to Replace Brake Fluid, right on the title screen).

Sometimes posts here treat brake fluid replacement and brake bleeding as meaning the same thing, but they don't.

For replacement, there's no air in the system, and if you do the replacement right, you don't let any in. The procedure shown works for that. If you do it wrong and let air in, you're no longer doing replacement, and now it's a matter of bleeding.

Bleeding to get air out is a process where a scan tool tells the brake computer to open the right valves in the actuator at the right times so the air gets out. There isn't a non-scan-tool procedure provided for that.

As far as the original question, I doubt there will be any problem having the traction battery out. The brake system runs entirely on 12 volts. It coordinates with the hybrid system to do regen braking when you're driving, but that's the only way the traction battery is involved.

That said, you will surely have one or two brake system trouble codes (C1259 and C1310, probably) indicating the brake system knows there's some hybrid system issue (like, the traction battery isn't there). That shouldn't be a problem unless those codes prevent the bleed procedure from running. I've never heard that they do.