ABS, brake and traction lights are on, but only sometimes!

I have 2013 Prius gen II. On one the coldest days of this winter ABS, brake and traction lights came on. Took the car to the Autozone near me for reading error codes. The Autozone guy tried to read error codes but couldn't and said this could be because some of the sensors got covered with ice. Couple of days later when weather got warmer I checked if the lights were still on. They were on at first, but after a couple of miles of driving they disappeared. So I thought the autozone guy was right and now everything is fine. But after some time the lights came on again even if the weather was not freezing. Then again disappeared. Three days ago they came on again only for a short time. I decided to find out what was going on and bought Mini VCI cable and Techstream. Scanning shows the code C1466 - Rear Speed Sensor RH Circuit. Does anyone know what that is? If something was faulty, then the lights should be constantly on, right?
Any help is appreciated.

 

Yesterday I cleared the error code with a pin method and the error code is gone for now. I don't know if it ever comes back or not. Before I posted the first post I went to a car wash. Maybe it was just a dirty sensor and it was cleaned by car wash and that's why the error is gone. Could it be just a dirty sensor or is it too far from being cleaned by car wash?

 

Thank you bisco.
So far so good. No lights are on for the last couple of days. But I still wonder what could trigger that error code and disappear. Yes, I will keep an eye on it and report back if it reappears.

 

Ok, the lights are on again. They are not constantly on, but sometimes on and sometimes off. Where is that hub and how do I replace it?

 

Thanks, I'll try that. I watched some YouTube videos about replacing speed sensors for other different cars, but could not find any video specifically for Prius. All of them were pretty straightforward, remove the wheel, locate the sensor, remove the bolt holding it, unplug the wire from the other end and remove the sensor. But in Prius the sensor is covered with a some metal frame and I could not find bolts holding it. You're right, I do need a repair manual for that project.

 

This video really helped to understand:

 

I thought my car was gen 3 too, but when I went to Toyota dealership for software update, the guy working there said it was gen 2. I watched some gen 2 wheel hub change videos, I noticed that gen 2 rear wheels don't have calipers at all whereas mine has. That means mine is not gen 2. Probably Toyota guy was simply wrong and I mistakenly gave him a benefit of doubt

 

I replaced the rear right wheel hub and now those three lights are on all the time. I checked with Techstream, the same error "1466 Rear wheel sensor RH Circuit" pops up.
Any ideas?

 

I'll try that too, if I find a not busy person, thanks. Meanwhile I ordered wire harness from ebay. I just did not want to believe that it could be because of the bad connection as the problem appeared only when I press on brakes. I was quite sure that it had something to do with the sensor itself. Are there any fuses to check additionally? I'll replace the harness and see if that solves the problem.

 

I replaced the harness, but nothing has changed. Then I thought maybe computer has to learn about the new bearing and reset the lights with pin method but the lights came on again. I checked the ABS fuses under the hood, all of them look fine. Then I checked with Techstream's Active test, as suggested by TMR-JWAP, I get all sorts of readings (reminder: my issue is with rear right sensor):



When I was changing the hub assembly I noticed that parking brake cable was not very tightly attached to the caliper, I mean it was fairly easy to remove its metallic round head from the caliper's hook. But it's not loose, just not very tight. Could that be the sign of something?
Any ideas are appreciated.

 

I don't know why but I was focused on the wheel acceleration part and did not even notice that each wheel speed data was there. That's a miss on my part. Thank you for pointing that out. You're right, RR wheel is 0 all the time. Is there any way to check if the new hub's sensor is working? I know one way would be to install that hub on the left side and see if it shows any values there, but that's a lot of work for just checking and plus I may mess up a good hub assembly on that side. I just don't want to move on to ECU before I know the sensor is not broken.

 

I am returning the hub that I bought through amazon. I watched some YouTube videos on how to check if speed sensor works or not. Such as this:

Turns out it can be checked simply by measuring AC voltage when spun, mine does not change at all and stays in 0. I hope this is the culprit, because I really don't want to dig into the skid control unit as it is allegedly located deep in the engine compartment and have to remove a lot of things to get to that.