We have a 2011 Prius Five with 78K miles. I was a block from home when the dash lit up. I pulled over, stopped, and then drove carefully home. A check of the codes by connecting pins 4 and 13 on the OBD2 connector and counting flashes gave these results: Skid light – 45 PCS – 41 ((!)) – 69 ABS – 42 TPS - 23 21 22 After clearing, the codes have not returned, but we have avoided driving the car except for occasionally moving the car from the street to the driveway to charge the accessory 12V battery. For about 9 months before this happened, we noticed a vibration while braking at very slow speed/creeping forward that worsened over time. We didn’t understand the significance at the time and couldn’t find any information online with the search terms that we used. In addition, we noticed more recently the brake pump running more and more frequently, even when the brakes weren’t being pressed. We suspect some sort of problem with the brake booster. What is the most likely problem, and can anyone recommend a repair shop in the San Diego area? Is it correct to assume that even driving to a repair shop would be unsafe and the car should be towed? Thanks for any feedback that anyone can provide. J & K
ABS 42 and skid 45 are both explained here: Blink (a/k/a Flash) Codes – How to. | PriusChat They both just mean "be sure to go look at the ECB ((!)) codes". ECB 69 is the trouble code C1391 and means the brake accumulator pressure doesn't go up fast enough when the pump runs, or it goes down too fast between pump runs. You already were noticing the pump running extra often, so this code is no surprise. The Gen 3 brake hardware under the hood is split into two packages: The cause of the C1391 and frequent pump running can be in either one, but is often in the upper package (the booster, not the booster pump). That's where most of the valves are that can get leaky with age. You probably can drive to a shop without incident. If the boost pressure drops extra low, you will hear a beepy alarm, and should be prepared to have to press the brake pedal very hard to slow the car. Three of your tire pressure sensors have stopped transmitting. Probably their batteries have conked out. A tire shop can get those sorted. I am no help with any codes on a PCS light.
Wow only 78,000 mi to holy crap I guess it must be more time sensitive than mileage sensitive it seems with these cars I guess in reality yeah 2011 car for me at this state of the game would have 200,000 miles on it so I wouldn't feel too bad about the brakes. But it's 78k I would not be feeling so good personally anyway this is a generation 3 and at this age it seems like mine these cars start to get very expensive seemingly a lot more than some other cars no matter so it's just something you just have to weigh out these two parts will be $1,500 they should be purchased new Toyota recommends them being replaced as a pair so on and so forth everything else on the car is in good shape the door panels on the two front doors look okay they're not caving in where the armrest section is attached to the rest of the plastic the interior's reasonably clean if you care about that sort of thing and all of that I would hope at 78K will be like a new car because for a Toyota 78K is not even broken in good but like I say stuff after 2009 seems to be pretty well planned obsolescence I hate even using that terminology but this stuff just seems like it and then moving forward now even the 2017 to 2022 stuff nah I'm not having it. The generation 3 will probably not be good to you going forward but that is subjective.
Thanks for the feedback! I made an appointment at a local hybrid shop for later this week. I was told that they have Techstream and can use it to determine whether the actuator, accumulator, or both are bad. Does this make sense? I forgot to mention that I cleared the codes—would this make a difference for diagnosis (considering that I already know that there is brake pressure problem due to the brake system 69 blink code)?
Well I'm imagining the codes will come back and short order if the problems are as stated and then when you get it to the place that has the TIS system in place and all that they should be able to read codes do diagnostics etc getting the parts separated for diagnostics is actually quite difficult hence you see Toyota recommending and generally replacing both of the pieces and they come out to about 12 or $1,400 together which is similar to other Toyota models that use similar brake parts like the generation 2 is $1,400 for a new break actuator The generation 3 they split it into two parts and for those two parts is about 12 to $1,400 catching on as we go?. But then you get to like 2016 and in a lot of these cars that whole mess changes to $140 rebuildable part that's available from all kind of suppliers yeah people got sick and tired of being sick and tired or something and the part doesn't look that different I have one out here on a Suzuki aerio very similar looking part mounted on the firewall I can take it off in 5 minutes yeah no kidding and the Suzuki aerio is I don't know 2011 or something 2009 very similar to the time my generation too was made.
OK, thanks. I was wondering if there is other information besides the codes that Techstream provides to help with diagnosis or whether there are additional codes besides the C1391, but it sounds like this may not be the case. I will have to press the shop more on how they can identify which part(s) is/are bad. It could be beneficial if the codes return within the 15-mile drive to the repair shop, but I don’t know if this is a long enough drive for this to happen, and I’d rather not drive the car farther than necessary in this condition.
Why not I drive the heck out of it. Get it to code get all the codes to really narrow it down a mechanics stethoscope is a good idea and then you can listen if you can get the car somewhere where it's quiet You can listen for leaks in the part that doesn't have a lot of electronics. It's a skill and that's about it like I say that's why Toyota generally recommends you just replace the both parts rather than have a problem and then have to do the labor again which is a bit costly just the mounting of the parts The bleeding and nonsense isn't too bad but they're charging for the job and/or the part.
Thanks again to ChapmanF and TomBukt2 for the information and advice. I had both parts replaced since the codes hadn’t returned by the time I drove it to the repair shop. They said that the brake master cylinder is the only bad part the majority of the time, but I decided to have both parts replaced to avoid the possibility of having to pay for labor a second time to replace the pump if needed. It’s great not hearing the pump running very often now. I’m a bit confused about part numbers, though. When I search my VIN on the Toyota parts site, it lists two “Cylinder Assy, Brake Master W/Fluid” parts that are “Exact Fit for your 2011 Prius”: 47050-47150 and 47050-47140. I don’t understand why there would be two different part numbers that would both work. Information on dealer websites varies, but I’ve come across a few that give more specific information saying that the 47150 part is for the model with 17” wheels as mine has, and 47140 is for models with 15” wheels. My invoice from the repair shop lists part #4705047140 for the “Gen-3 Brake Master cyl, Accuator [sic]” (AKA Brake Booster Assembly?). Does anyone know whether it is OK to use this part with 17” wheels, and if not, what problems it would cause? Thanks!
