Successful ABS actuator/accumulator replacement

Hello all, I just finished my ABS actuator/accumulator replacement after a few hiccups - I wanted to post some notes here, in part because the community has been very helpful, and wanted to document some of the lesser known bits of information in case someone needs to google it in the future.

2010 Prius, 3rd gen, north american, 168k. In very good condition overall, was driven mostly by a little old lady (my mother in law, so i know it's not a story) mostly in northern CA but also recently in the northeast. Well maintained, in the later years, mostly by me. My daughter drives it mostly now, since grandma doesn't drive much anymore.

Daughter was driving it, with me, back home from an event, and the brake light(s) went on - traction control, ABS, and BRAKE. There may have been another, I can't recall. Luckily I was there in the car, we pulled over and I test drove it. Brakes were soft for sure, but I couldn't tell exactly how soft since I don't often drive the car. After a few minutes googling and checking to ensure we still had brake pressure and no leaks I felt comfortable driving it the 10 min home on side streets. Halfway home, the lights all went away, brakes firmed up and it drove normally.

Some research at home indicated that the ABS system was likely starting to fail, either the accumulator wasn't creating enough pressure (the bottom thing) or the ABS module couldn't hold the pressure (the top thing). Car is in good condition and enables my teenager to get around so I took it for a quote. Two quotes came back at $4000+ so after some consideration I decided to do it myself. Bought both parts at Olathe Toyota (those guys are awesome btw) for $1200. FWIW the part numbers for my 2010 were 47050-47140 and 47070-47060. These are the current replacement parts as of June 2025.

The physical replacement of the parts is straightforward, watch enough youtube videos and you can figure it out. I won't get into it. It takes basic tools, although I will say that having a set of line wrenches is very helpful, I highly recommend them to ensure you can remove/tighten/loosen the lines without stripping and rounding the fasteners. Also a set of hose clamp pliers is helpful also. Honestly if you're going to attempt this repair I highly recommend both if you don't have them. Don't screw up your $1200 repair because you used an open end wrench instead of a $5 line wrench. Buy the right tool, cheapskate.

Parts installed without much issue, although positioning the accumulator with the little shock absorbers, is a pain. Parts installed without an issue.

First problem I came to is the car would not go IG-ON mode which is sort of required for the air bleeding procedure. When I hit the button once, it would automatically go into READY mode. I could not figure out why so I bled the brakes out normally and it seemed to work, I got it to the point where I had hydraulics at least. There did not appear to be air in the lines, or in the ABS module. But without being able to go to IG-ON (the mode where the car is on but the engine is off), I could not successfully know that I did air bleed correctly, and I could not do the linear valve offset reset.

One thing I noticed was that when I turned the car on the brake lights automatically turned on at the rear of the vehicle. Eventually i figured it out, and it was very simple - the brake switch that contacts the brake pedal, needed to be re-adjusted. It's a simple twist and click to adjust.

With that done, I re-did air bleeding on all 4 corners and the abs module. The scanner I used was the Foxwell 614 elite. That seemed to work fine (and to my credit there was no air in any of the lines from the first bleed)

With those codes gone the only ones remaining were for linear solenoid valve offset and LSV learning undone.

I tried the procedure through my scan tool and it would go through the procedure but nothing would happen. No noise, no blinking lights on the dash as I've seen in other videos, nothing. After some research i suspected battery, so I checked it and it was at 11.8-11.9, it's a 6 month old battery but i put it on the charger anyway. After a while i checked it again and it put out a steady 12.1 and i tried again and still nothing.

I'll skip all the intermediate troubleshooting steps but the solution ultimately was, the 12v battery. I hooked it up to my van like it was being jump started, and apparently that was finally enough voltage to do the linear solenoid valve procedure. Unlike before when nothing happened, this time, there was all sorts of whirring clicking and air pressure noises during almost the entire procedure. I actually then cleared the memory and did it again.

Regardless it worked, and no i just need to put the rest of it back together (wiper arms, motor, cowling, etc). Test drove it, everything works fine. Final cost ~$1500 (scan tool was an upgrade over my old reader) and many hours of troubleshooting, but saved many thousands of dollars.

Again I just wanted to document this in case anyone searches in the future and is stuck by either the brake switch issue or the 12v issue. I have spent many hours on this site and others learning how to do this, and that wouldn't be possible if others hadn't documented their experiences so I wanted to pay it forward.