Same ol' VSC, Brake, ABS Warning lights

I have no idea what you can or cannot do regarding automotive repairs.

However, if you are serious about DIY, you need Mini VCI so that you can retrieve the DTC logged by the skid control ECU. If you don't have the DTC then you really have no idea what is wrong with the car.

It would also help if you are precise regarding exactly what warning lights are on. Take sharp photos of the warning lights and any warning icons in the upper left corner of the MFD, and post.

 

There are a few things you can do regarding DTC C1253:

1. Find the ABS MTR and ABS MTR 2 relays. Remove each relay and check the relay by applying 12VDC to the relay coil terminals and measuring resistance across the switched terminals. The resistance should be 0.5 ohm or less after accounting for the digital multimeter lead resistance. Use the ohmmeter to determine which are the coil terminals (resistance will be ~100 ohms or so.)
2. If the relays are good, then you will need to replace the brake actuator. You can buy a used one for ~$200 or so. You will need to remove the sheet metal cowl tray (which houses the windshield wiper motor) for access to the brake actuator.
prius brake actuator 2008 | eBay
3. If you get to #2, then I suggest you subscribe to techinfo.toyota.com so that you have access to the factory repair manual info.
4. You will also need Mini VCI to refill the brake lines with DOT3 brake fluid and get air out of the system. This is the Mini VCI that I had bought:

So if you mess up, it is not the end of the world - you can have the car towed for help. However it sounds like this is well within your comfort zone if you do the needed homework and have the proper tools and Mini VCI available.

Use the multimeter to measure the 12V battery voltage when the car is IG-OFF. A new 12V AGM battery fully-charged will measure 13.0V. A discharged battery will measure 12.0V. See what the battery measures. If it is below 12.6V, put the battery on a charger, 4A charging position if available, overnight.

I noticed that the fuel gauge is reading one bar, so fuel should be added in the very near future. You don't want to run out of fuel with the other problem that the car already has.

Good luck.

 

1. Yes, you need a 12VDC source. You could use two 6V lantern batteries wired in series, as an example. You need to engage the relay coil to make sure the relay actually works. Using your finger doesn't count because your finger is not going to be there to hold the relay contacts closed when the car is being driven.
2. Look on amazon.com for Mini VCI.
3. If you are going to buy a battery charger, get one specified to work with 12V AGM batteries. Another charger will not bring the battery voltage as high as it needs to be to be fully-charged. You need a charger that will produce at least 4A charging current.

Why is the fuse box missing its cover? Is this an accident vehicle that had been totaled, repaired and resold? If so, that might help to explain why the car has this problem now. It is really not helpful to have the electrical circuits exposed to water splashing in under the engine compartment.

You ask how unsafe the car is to drive. It is as unsafe as any other vehicle whose braking system might give out at any moment.

 

How many miles has the car been driven since the two relays were replaced? If the DTC does not come back after 500 miles have been driven, then you can declare victory.

One possibility would be that the brake actuator pump motor runs much more than normal. This demonstrates that the system is not maintaining hydraulic pressure to the extent that it should.

 

Well, if no warning lights are on then I would say that all is good.

 

I think you should hold the letters until next week when you've logged a total of 500 miles without any problems. If the problem reoccurs soon and you need professional help, you may regret burning your bridges.

 

For future reference, when my actuator was failing, the pump would run every 10 seconds or so while I was driving and not braking, but the brakes otherwise worked fine except for losing the brakes twice when I jumped in the car and put it in reverse right away after starting; it didn't have time to pressurize the brakes. The first symptom I noticed was that the pump seemed to run longer after I shut off the car, more than the usual few seconds.

 

I'm new on this forum & I live in Singapore but I'd like to share some info which might interest you all.
I have a 2nd Gen Prius imported from Japan. A few months ago, the chirping sounds started & the mechanics said that the brake actuator is dying. A fortnight ago, the ABS, VSC & brake warning lights came on & the alert sounded. I searched & found that there was a recall for this very problem on Toyota Japan website - toyota.jp/recall/kaisyu/150708.html entitled プリウスなど7車種　ブレーキアクチュエータの修理 which means Prius & 7 other models - Brake Actuator Repair. The phrase "平成15年から平成24年に生産したプリウスなど　7車種の一部車両につきまして、下記内容の修理（無料）を実施させていただくことに致しました。" is saying "Repair (free-of-charge) is in order for Prius & 7 other models manufactured from 2003 to 2012". "ブレーキ頻度の高い厳しい使われ方により、ブレーキアクチュエータのソレノイドバルブシール部が摩耗し、フェールセーフモードに入り、警告灯点灯、警告音吹鳴、ブレーキの効きが低下することがあります。当該現象が発生し修理をご用命の場合、下記の通り無料にて修理対応致します。" means "Due to frequent use of the brakes, the valve seal of the solenoid in the brake actuator gets worn & the system will enter a fail-safe mode with warning lights & sound. Braking performance will be degraded. When such phenomena occur, and repair becomes imperative, you should follow the instructions below to get repairs done free."
The part 【 従来の保証期間 】新車を登録した日から5年または10万Km以内 → 【 無料修理対応期間 】平成29年12月末迄：全車無料修理. 平成30年 1月以降：新車を登録した日から9年以内 says that the 5 years or 100,000km warranty is superceded by a free repair period ending Dec 2017 after which this recall applies within 9 years of registration of all new cars. The table of 7 models has Prius at the top of the list. プリウス ZA-NHW20 DAA-NHW20 NHW20-0001002～NHW20-0133242 平成15年 8月～平成16年10月 Aug 2003 to Oct 2004, NHW20-3000002～NHW20-3589297 平成16年 9月～平成23年12月 Sep 2004 to Dec 2011 and NHW20-7000000～NHW20-7894049 平成16年10月～平成21年 3月 Oct 2004 to Mar 2009. My car chassis number is NHW20-3410902 so it is covered under this recall. Yet when I wrote to Toyota Motors for the repair to be done, they claimed that my car (based on VIN) was not part of the recall. I challenged them as I did not reveal my VIN to them. Until now, they are not responding to me. As there are many similar failures, I suspect that Toyota is trying to protect its reputation in its home market but is hoping that nobody else notices that they are treating overseas customers as second class.
Any one has any ideas what we should do to correct the situation?

 

Thanks for paying attention to the Toyota JDM market and recall info. It looks like this bulletin was issued in 2015? I doubt you have any recourse since the JDM warranty likely is limited to vehicles physically located in Japan.

Those of us in North America hopefully will see TMS USA issue a TSB on this issue soon.

 

I have the same lights on in my 2012 Prius C, brake fluid level it's where it is supposed to be, they turned on while i was driving on the highway at 65 mph, the vehicle brakes normally, just that it does not have regenerative braking now. Could it be an ABS sensor or something? like a wheel speed sensor, of course i have not scanned it yet.