2010 Prius: Intermittent Dash Lights & No Regen Braking

Thank you for the info, here’s a longer video showing all…
the booster/accumulator can be heard as well…

 

Did my post, along with the earlier video, clarify how to count the blinks?

 

Yes, thank you, I dont have access to a manual, Ill do more research.

 

If you can count the blinks yourself (kind of the tedious part ), we can help with the codes.

Also, there are a bunch of ways to get access to the repair manual, one might work for you:

Toyota Service Information and Where To Find It | PriusChat

 

All of these are correct, the VSC (on left) is flashing 54.

I’ve ordered a used master/pump and accumulator, hoping a swap will work.

 

I don't think there is a 54 VSC code, but there is a 45, in case you might have flipped the digits. (There is a way to tell—the pause between codes is longer than the pause between digits of the code—but it's easy to miss.)

VSC 45, like ABS 42, just means to pay attention to the ECB code(s), in this case your 69.

 

Yes you’re correct, 45.

Apparently once they are installed we have to do a brake fluid bleed & also a master cylinder calibration, which requires a “good obd sensor” or the toyota software …

 

Sorry, this thread kind of turned into part-yours-and-part-refusedone's. You're the one with the C0210/33 and C1238/38.

Those are both about the wheel speed sensor signal from the right rear hub. If you wanted to just try blindly replacing a part, the right rear hub would be the part. That might not lead to success if the problem turns out to be something else, the wiring from the sensor to the front of the car, for example.

Another way to proceed would be to look up the troubleshooting steps in the repair manual for those codes, and follow those, to help pin down what has actually caused them in your car.

Toyota Service Information and Where To Find It | PriusChat

 

In my case I’ve determined that the accumulator pump keeps kicking on because there is a leak in the master cylinder pump assembly …I can hear a repetitive clicking after the accumulator kicks on, using a mechanic’s stethoscope, it’s coming from the master cylinder assembly ….so I’m thinking I need to replace them both.
I’ve ordered them, and also going to need techstream as apparently it is necessa to run through its “brake bleed/calibration “ to get all the air out of the master cylinder assembly after install.

It sounds like your symptoms were similar so I thought I’d share what I’m planning…

 

Note that you and myselfnjit have completely unrelated trouble codes. You (refusedone) have a C1391/69 code, indicating pressure leakage from the accumulator.

The codes myselfjnit has are C0210/33 and C1238/38, referring to a wheel speed sensor, and C1214/62 about a pressure regulation issue while applying the brakes.

In a way it's unfortunate these two quite different situations are being discussed on the same thread, but it's a forum and that happens sometimes. Just need to work extra hard to keep the two straight.

 

Thank you for your clarification & all of your help throughout! Would you say it’s a safe bet that swapping out both is the way to go here?

 

With your C1391, swapping both units is indeed what an owner with enough money and a "just cover all the bases" mindset might choose to do.

 

Yes, those codes are about the signals from (both) rear wheel speed sensors.

The sensors get power from the skid ECU under the hood, over wires that run all the way back to the rear hubs, and send signals back to the ECU over the same wires. The codes are the ECU saying the signals look funky. So the troubleshooting will pretty much focus on that wiring and those sensors.

There are about 26 pages of troubleshooting steps in the repair manual (13 pages for the "speed sensor circuit" codes 33 and 34, and 13 for the "maybe stuff stuck to sensor tip" codes 38 and 39).

Toyota Service Information and Where To Find It | PriusChat

If a sensor is new and there's still a code (assuming the new sensor is also of good quality), that might cast more suspicion on the wiring if that wasn't checked before.

By the way, you'll see in the repair manual that the ECU offers an extra-sensitivity "please test my newly-installed sensor" mode where you drive a certain test pattern and the ECU grades the sensor signals very strictly. I recommend (like the manual does) always performing that test after changing bearings or sensors. If you do that test and it passes, you can be pretty sure things will be trouble-free. If it doesn't pass, you know right away, not when a maybe marginal signal triggers a normal code weeks later.