ABS Brake warning lights

I'm fighting a similar problem on 2004 w/ 83kmiles. Red "Brake" light and ABS light and ((!)) lights are on all the time. I checked fluid level, a bit on the low side, so added a little bit. Problem still there. Jacked a wheel at a time and checked brakes on each wheel. Found Hydraulic brake on right rear was not working, but the brakes on the other 3 wheels worked OK. I checked the brake actuator in the right rear and found both pistons to work very freely, with no leaks. I don't know where to look next. Does anyone have any ideas.
I saw one person reported a problem with a connector on a brake pump. He fixed by simply disconnecting and reconnecting. Where is this pump located and how do you get to it?
How many independent hudraulic circuits are on the Prius?

 

I am assuming that your method of checking the brakes is to raise up a wheel, then have a helper depress the brake pedal while you try to spin the wheel. Am I correct?

If the RR brake is not working, then it sounds like the brake actuator assembly needs to be replaced. This is a squarish assembly located near the firewall in the engine compartment, that has multiple hydraulic lines going into and out of it. The assembly contains several solenoids that route the flow of brake fluid. Each wheel has two solenoids associated with it. My guess is that one of those solenoids for the RR brake is stuck.

It's really not a DIY job to replace due to the need to use the Toyota diagnostic laptop when bleeding air out of the system, recommend you have a Toyota dealer tech verify the diagnosis and repair. My guess is that this repair will cost ~$2K.

 

Thanks, Patrick. Yes, I did use a second person to press the brake pedal while I manually spun the jacked-up wheel.
Is there any way to know that the problem is the solemoid valve versus a problem with the control system giving a bad signal to the solenoid valve?

 

Without any warning yesterday the ABS, (!) and alarm went off... Brakes are hard and not safe to drive. Based on what I have read the Brake Actuator, Hydraulic Brake booster of some combination of things have gone bad and I am looking at a $2,500 to $3,000 repair bill. Is any of this covered by my extended warrantee?

 

This should be covered by your Toyota extended warranty. Odometer reading?

 

The odometer reading is 68,500... just under the 70,000 limit I think.

 

Thanks ... It was covered by Toyota Extra Care Policy... The cost $2,485.. So the investment in the extended warranty was worthwhile.

The policy covers the care til 2011 or 75,000 miles.

I still have concerns about the batteries and the cost of replacing them. I had to replace the primary or standard battery.. 5 yrs old and was weak... cost $219 including a labor charge?

I love the car, drives great. I am thinking of a conversion kit to make it a plug-in with more batteries. Do you have any information ont this?:der:

 

Regarding the 12V battery, most Toyota dealers sell that part for ~$130 or so. If you paid $89 for labor that is pretty good, some dealers are not ashamed to charge $300+ for the job.

Regarding the cost of the traction battery, if that fails outside warranty my advice would be to purchase a salvage battery from a recent model year Prius, for <$600 or so.

I don't have recommendations regarding PHEV except to offer this observation: If you are concerned about the cost of battery replacement, why would you convert the car to PHEV, which results in greater reliance on batteries with a shorter useful service life?

 

Ditto Patrick. Also, PHEV conversions cost about $10,000.

 

I should have replied to my own message sooner. I took the car into our Prius dealer with a letter explaining everything I tried. They checked the ABS computer in the car and found only the "low-fluid" indication that I had reported previously. They reset the ABS computer and did nothing else. They checked the brakes while the car was jacked up as well as a short road test. The brakes worked fine without replacing ANY hardware!!!!

I was happy that I did not have to pay for a new master cylinder or any other parts, but I was frustrated that the penalty for the brake fluid being a bit low was so severe to cause all the brake panic lights to come on. This I believe is an ABS computer software issue that should be fixed, if it hasn't already been done. 4/28/11 DoctorL

 

I should have replied to my own message sooner. I took the car into our Prius dealer with a letter explaining everything I tried. They checked the ABS computer in the car and found only the "low-fluid" indication that I had reported previously. They reset the ABS computer and did nothing else. They checked the brakes while the car was jacked up as well as a short road test. The brakes worked fine without replacing ANY hardware!!!!

I was happy that I did not have to pay for a new master cylinder or any other parts, but I was frustrated that the penalty for the brake fluid being a bit low was so severe to cause all the brake panic lights to come on. This I believe is an ABS computer software issue that should be fixed, if it hasn't already been done. 4/28/11 DoctorL