2016 Prius Braking power low warning

I test d the 12v was 12.2 v
Regardless I changed the battery 2 days ago. It's a new 12v battery now.
All eror and displays disappear after I'm turning the car on/ off several times. It is ok now.
I will try to replace the pump motor relay (c1253).

 

This post by Patrick might be worth a read . He has a njinja rep in this forum, even if he hasn't been around much lately.

abs main fuse | PriusChat

 

The post above was only a hint. Hinting that it could be in your best interest to get a 2 day sub to the repair manual, or try to get blink codes from the brake ECU.

 

My problem here is intermittent. Right now I don't have any dtc .
The fusible link is just an array of fuses. Not a relay.i might be wrong .
They sell it at the dealership for 30$.
I don't have any blown fuses now. And car functions 100%. But I do have a feeling this problem will come back because I only changed the battery which yet tested good (12.2v) but was 6 yrs old . when this abs failure happens it sudden and it takes 1 minutes for the car to be ok again after turning on/off several times . Yet very dangerous for me. I don't think problem is gone.

 

an uopdate
been now 300 miles and 8 days since i changed the 12v battery. car drives fine and all dtc codes disapear, is it time to be a little optimstic?

 

i am!

 

Any update?

 

Yes.
I have changed the 12v battery.
After that, it happened twice again In the same ride.when on May , 2 months ago, I was in Sequoya park on the way down from about 10,000 ft. It was a stretch of about 10 miles downhill. Lots of slalum braking.
After that and about 4000 miles more of normal driving, it didn't happen anymore.
I think this long downhill was too much.
It took me over an hour to do that stretch. Had to drive it down at a speed of 5 mph.
last week I checked those codes with the O'Reilly's scanner. All dtc codes are still there. Car is fine.
Thanks @bisco and all others

 

MID messages like "braking power low" are talking about the power to assist your braking (that is, the fluid pressure stored up in the accumulator). Codes that are about the pump motor having to run too long, or pump motor relay problems, or fluid leakage, or sticking accumulator pressure sensor readings, all could fill in some details of that picture. When the power to assist you is low, that means the brake pedal is going to feel hard/stiff and you will have to step on it very hard to slow the car.

The repair manual will have troubleshooting procedures for whatever specific codes you have. I can't think of any real easy shortcut to just working through those.

Toyota Service Information and Where To Find It | PriusChat

 

Makes sense.
Also. Last month I decided to change the front pads and bleed the lines cause I already bought it
To my surprise the pads (originals and 9 yrs old ) had about 70% on them.thats on a car with 250k miles. I did the bleeding too.
All that was after I changed the 12v.

 

New here, Same thing happened to me. Been searching for any solution because don't want to take it to a dealer straight away as they all are rip off... 2016 Prius with 175k miles. The codes are:
c1241- low/ high power supply voltage
c1252 - brake booster pump motor on time abnormally long
c1404- Malfunction in rear speed sensor LH circuit
c1408- open or short in rear speed sensor LH circuit
c1416- rear speed sensor LH circuit output
c14D5- accumulator pressure sensor stuck

Changed the 12v battery but not solved. Any help...? Anybody solved the issue?

 

how old was your battery?
are your brakes fumctioning right regardles of warnings?
maybe its just the rear speed sensor,

 

You have multiple indicated issues there. At least, one that involves the left rear speed sensor, and one that involves pumping up accumulator pressure.

The three codes about the speed sensor are, of course, a related group, and the pressure sensor and pump run time are probably a related group and could be related to the supply voltage code (if the pump doesn't get enough power, its run time increases), but that's not a sure thing.

A scan tool that can display freeze-frame data from the C1241, C1252, and C14D5 codes would be a very handy thing to have access to right now. I would want to see just what was going on when those codes were logged. (In particular, the question of whether the pump run time was influenced by supply voltage would be illuminated by seeing what the supply voltages were when the pump code was logged.)