Regen Breaking stopped working

They are call brakes, not breaks. A break is a rest period.

As to the problem, note the ABS light on the dash. It is telling you to read the trouble codes and find out what's broken. Since it started when you got the brake pads replaced, I'd guess that your mechanic did some kind of damage. Perhaps a wheel speed sensor. Reading the codes will save a lot of guessing.

 

I'd wager it's a connector on the wheel speed sensor wire, they are very sensitive. You could do a quick visual or gentle pull test if you know what you're doing. Or you could take it back in and I'm sure they'd read the codes, there's a very good chance it's on them anyways.

 

Reading the codes is fast and will point you that direction, if that's the direction. For the brakes, no scan tool is needed to get the basic codes:

Blink (a/k/a Flash) Codes – How to. | PriusChat

 

Who did the brake job? Prius brakes are tied into a lot of electronics, need to be approached "delecately". There is a procedure to set the car in "invalid" mode, for whenever brake fluid is being expelled at the bleeders.

Even when you're not doing any bleeding, there's issues. For example, if a caliper is off a rotor and the driver's door is opened, there's a good chance the system will try to pressurize, and pop the piston out. My tact in such scenario is disconnect the 12 volt battery cable before doing anything, and when everything is back to gether pump the brake pedal to take out excessive travel, and only then reconnect the battery.

My 2 cents: when you've dropped $30~50K on a vehicle, the Shop Manuals should be available to you, for free.

I was just struggling with rear brakes on a Mazda CX-5 (with electronic parking brake). Should have googled much sooner, but eventually did and found there was a chicken dance for retracting the pistons.

 

To be a little more specific about the risk, it's not so much that the system pressurizing will pop a piston out. The pressure in the system doesn't reach the calipers except when the actuator sends it there (unless the actuator has actually failed and is leaking into a brake line). You know this, of course, because the system pressurizes as soon as you open the driver's door and stays pressurized the whole time you are driving, and if that meant pressure was reaching the calipers, the brakes would be dragging all the time.

However, there is a self-test that the brake system can do while the car is off, and in the self-test it does apply pressure to the calipers, and that sure enough will pop one apart if it happens at the wrong time.

In a Gen 3, you can hear that happen if you listen closely 90 seconds after shutting off the car. It is a click squish click click squish click from the brake pedal area, the very sound of solenoid valves in the actuator opening and closing and directing pressurized fluid out to the brakes.

 

I'd cut him a brake...I mean break.

Mike

 

Right, that's why I linked to the procedure for finding the error codes your scanner didn't show you.

Which you then almost used ...

... by going to a youtube video instead that showed you how to start the same procedure, but ignore the codes being blinked out, and just pump on the pedal to clear them.

Which is why now nobody knows what codes you had.

With any luck, maybe they won't come back, or if they do come back, you'll actually read them.

 

Both of those codes are covered in this link, given above in post #4:

Blink (a/k/a Flash) Codes – How to. | PriusChat

42 on the ABS light and 45 on the VSC light both mean "hey, be sure to look at the codes on the ECB light". That's the one that looks like ((!)).

So, what was that light blinking?

 

C1391 / 69 is a failure to hold fluid pressure in the brake accumulator. Usually there is an internal leak allowing fluid to return to the reservoir, not an external leak where any fluid would leave the car.

The problem can be in either of these units under the hood:



Sometimes a mechanics' stethoscope can pick up the sound of leaking in one unit or the other. The top one is the odds-on favorite, because it just contains many more things that can start leaking.

Do not clear the C1391 code ... that code may make you eligible for free replacement under service campaign ZJB, if your car has under 150k miles and was put in service under 10 years ago. (If you're getting close to your 10-year in service date, see the dealer soon.)

 

The ECB blink code 69 = DTC C1391 "Accumulator Leak Malfunction".

Now you can search this forum for trouble code C1391.

Edit: ChapmanF responded while I was typing my response. See his reply above.

Posted via the PriusChat mobile app.

 

Ive been dealing with the same codes & symptoms, if you find that it is a sensor or something please share. I’m planning on swapping out both pumps pointed out above…

 

There are certain things it kind of can't be. The pump raises the pressure of the brake fluid in the accumulator. Supposing it were running repeatedly like that because of a sensor or something, the pressure would be getting crazy high.

For the pump to be able to keep continually pumping like that, it has to be because the pressurized fluid is going somewhere, so if that symptom's being observed, the C1391 code has to mean what it says it means.