Disengaging my ABS

There is only one electronically controlled brake system, and if it’s leaking, it needs to be fixed. The fail-safe design is meant to give you enough warning to make repairs before braking performance is seriously degraded, not to let you ignore the problem.

If the warning lights are on, ABS has already been disabled. As Toyota writes in the Repair Manual (more info), “When a malfunction is detected in the brake control system, the skid control ECU turns the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights come on, as well as prohibits ABS, BA, TRAC and VSC operations” (emphasis added).

Has the dealer checked if the repairs might be covered under Toyota’s Customer Support Program ZJB, for which DTC C1391 was one of the symptoms, or other programs or safety recalls?

 

I feel your pain, just had same happen to my 2010 and the stealership wants $3500+ to fix it. Have you addressed you issue? I plan to deal with it myself but need to find the parts for a better price.

 

To you have any trouble codes present?

 

as Ihave found: the dash lights up and u hear thecontinuous loud tone ... but the C codes arent picked up by normal (obd2 code readers) ...(at least on gen2)

 

That’s not a surprise: the regulatory mandate for OBD II covers only engine and emissions diagnosis. As far as I know, Toyota had (and has) no obligation to provide any standardized means to read DTCs from the skid control ECU, for which their current solution is the Toyota Techstream diagnostic system.

Without a Techstream system (or a third-party equivalent), you can still read many brake-related DTCs as blinking patterns using the TC-to-CG method, discussed extensively in other threads.

 

so i found the TS and got the system read for ABS/VSC/TRAC :
2 items:

C1252 "Hydro-Booster pump motor"

C1256 "Accumulator Low Pressure" (which also had FF data)

The pump running longer and more frequently than normal to maintain pressure is consistent with failed pump symptoms - I was hearing a pump noise and wondering what it was ..

 

A person on a budget would next work through the roughly ten pages of simple tests in the repair manual, in order to pin down what actually caused those codes, and then fix that.

A person with no budget would probably look at those fortune-cookies shown with the codes, assume the problem was the actuator, replace that, and then backtrack and do the tests if that didn't fix the problem.

 

dang brake section sho nuf do b a long mutha .. 240 pgs .. -- but it will be a simple 10 page diagnostic .. and a miracle may happen .....

 

There is nothing wrong with getting familiar with the whole section, and you learn a lot about the brakes that way, but yeah, once you flip to the page for the codes you have, it's about ten pages of workup to pin down the cause.

 

Yes.. its deep .. its a big system .. one would not feel too motivated unless already being prodded by the need to use the car hammpered by the brake ....

I see the brake system has it's own power supply.. brake control power supply ? who would have thought brakes have an additional power source ? -- has anybody heard of this going bad ? like an aux battery that lasts 5 yrs or less... when the car is 16 yrs old .. u have to wonder ...

 

Got mentioned just recently in a different thread ... that's a Prius v thread, and the system is different there, but it mentions some differences with Gen 2, and the Gen 2 power supply, near the end of that post.

 

interesting.. there is alot of safety and redundancy built into this amazing piece of tech called prius : currently, I will attempt to address the C1256 'accumulator low pressure' error.
I have disengaged the 12v and will then pull the 2 MTR relays as outlined on BC-117 and then check for the voltages there - this is a 'wire harness check at the engine room relay block-battery' -
i think i was supposed to try and clear the DTC's prior .. --- well .. that brake buzzer is annoying enough to make anybody not want to drive the car ...

... as predicted .. the wire harness checks out fine with proper voltages in those 2 relay connectors.

I was able to clear .. and the c1252 didnt come back .. however the 1256 did and the annoying continuous tone that comes with it ...

 

u can buy just a pump .. or u can buy the whole 'block' ... if the pressure is down isnt this the pump .. or is it the thing that's leaking that caused the pump to work overtime and fail ?

just the pump ... with the 12v connector .. small aluminum block and output
2004-2007, 2009 Toyota Prius ABS Pump - Genuine W0133-1769993