Brake, VSC, ABS, and (!) lights on, losing significant braking power

Should be very simple to diagnose. Once you get the parking brake and automatic adjusters to work everything else should work as well. If e-brake cables are working fine then probably it’s just easiest to replace brake shoes and hardware. And clean and lubricate everything.

Once I was working on a (different car not a Prius) where automatic adjuster always slowly tightened the brake shoes too tight and brakes dragged. It ended up being that brake shoes in it were wrong type. They fitted in it fine and looked new so I didn’t want to replace them in the beginning.

 

How regularly does the parking brake get used in your car? I ask because I believe you have the "parking brake type" of automatic adjuster (the adjusting screw and star wheel are located up high in the brake assembly, not down low, and use of the parking brake is what makes it adjust). Any single use of the parking brake can only change the adjustment by 0.03 mm, which is plenty to keep up with normal lining wear as long as the parking brake is regularly used (and the adjusting lever and springs are properly assembled, the starwheel teeth are not rounded off, and the adjusting screw isn't gunked up, and turns easily).

Symptoms like yours (with the parking brake travel consistently getting worse) would suggest one of those problems: the adjusting screw doesn't turn easily, the starwheel teeth are rounded off (maybe even just one tooth, if it happens to be the one the lever is aligned with, it will just keep slipping over that one tooth, and never turn the wheel), or the lever/springs got assembled a bit strangely and aren't properly engaging the starwheel. A lot of this is pretty easy to see just by sliding your drum off and looking. A less likely story could be if the parking brake is getting used very seldom and there's more than 0.03 mm of lining wear in between uses, but that would be a lot of wear....

Anyway, now that you've got dash lights on also, you should not just assume they are telling you about the same problem you already had. They might be, but you need to have the trouble codes read to find out. Nothing stops you from having more than one problem at a time, so it's important to ask the computer now why it's turning those lights on.

-Chap

 

Woops, I see that you are in Finland ... do you have rear drum brakes, as we have on Gen 2 in the US, or rear discs?

We didn't get rear discs until Gen 3. That adjusting mechanism (assuming it would be the same for you) is hard to see without disassembling the caliper. It consists of a threaded post, a sleeve nut that is free to spin on that post, except for a wound-spring clutch that allows the nut to turn only one way, and a piston with notches in the face that engage a pin on the back of the brake pad to prevent the piston itself from turning. (That last part is the only part you can visually confirm without taking the caliper apart.)

A brake job that didn't use pads with the proper pins, or didn't engage them correctly with the piston, or a caliper rebuild that didn't reposition the spring clutch properly, might cause the adjustment not to work.

Toyota also had another system for some cars with rear discs, where the rotor was hat-shaped and the parking brake just used a tiny pair of conventional shoes in the middle ... I'm assuming that's not what you've got.

-Chap

 

If all of those warning lights are on, then the skid control ECU logged diagnostic trouble codes. The first step is to determine what the fault codes are.

 

I was just giving advice to Golperius. I know North American gen 2 Prius does have rear drum brakes. We do have rear discs here and e-brake is drum brake inside of the disc but that has nothing to do with my advice to Golperius.

Basically your advice for drum brake is the same as mine anyways.