C1256 low pressure accumulator- ABS beep

Holy Crap, this is an old thread! Feel free to start a new one.

 

Thanks for the info, and yes I meant "hydro". Can you tell me which relay and/or fuse supplies power to the ABS module and the Accumulator pump? I think ive checked everything, Im just trying to be thorough and make sure I haven't missed anything.

 

Those two HYDRO MTR relays are what serve the accumulator pump. HYDRO MTR NO.1 relay is fed from ABS NO. 3 fuse, HYDRO MTR NO. 2 is fed from ABS NO. 2 fuse, both of which are in the "Engine Room Main Wire and Engine Room J/B (Engine Compartment Left)".

The actuator itself is fed by ABS NO.1 fuse and ABS SOL RELAY, both located in "Engine Room R/B No.2 (Engine Compartment Right)".

What's your issue? Do you have access to the wiring diagram?

You might be interested in a post I made a couple years ago about exactly how the system monitors the performance of the accumulator pump.

-Chap

 

The ABS solenoid relay is green, in the passenger side fuse and relay box. Labeled ABS|Tec|Relay. 2 sets of numbers on it
88263-24030
056708-9800

From my 03 Prius. Hopes that this helps.

Putting mine back in, now.

 

Thanks for the info. All the relays and fuses test fine. Next question, toyota part number for the accumulator pump assembly. Or can the pump be easily removed from the assembly and replaced?

 

You can look for a thread by rlin78, who was able to replace the unit without having to evacuate-and-recharge the A/C, by taking a leisurely ~ ten hours to do it.

What's up with your pump? Have you checked? Seized? Drawing too much current? Drawing too little? Getting inadequate voltage?

-Chap

 

im talking about this
4707047020 https://sep.yimg.com/ca/I/yhst-19630673577839_2267_69861962

problem im having is inconsistent brake. Sometimes its solid, sometimes its soft, sometimes I have to pump it up. No air in the system, not losing fluid. Abs and brake light only come on if if its soft and i force it to the floor. Sometimes though its solid and i can stand on the pedal and not lose any pressure.

 

Yes, that is what we're talking about.

That's a good description of symptoms, but I was asking whether you had gone further in identifying what is causing them. An electric pump motor could potentially seize (usually recognizable because it draws higher current than normal), or it could have brush wear (and maybe draw lower current than normal), or could be ok but suffering from inadequate power reaching it, or an inadequate ground connection. In an earlier post I linked you to a description of how the brake computer monitors all those possibilities so as to be able to tell them apart if you ask it. I was wondering if you had.

Pinning down whether the problem is the pump itself or something up- or downstream may help you, because if you rule out the pump, you save not only the price of that animal, but possibly ten hours of elbow grease.

-Chap

 

I am having same problem .. did u had any luck solving this problem?

 

I never got it fixed. I know its not the most cost effective way but im gonna throw some parts at it. Gonna order a used brake abs, booster pump, and accumulator assembly off of Ebay. Found the whole assembly for 120 bucks.

 

When I got my $400 02 from texas, replacing the pump assembly solved all problems with the brakes. I bled my brakes with a vacuum tool from Harbor Freight. There is hope. My pump was $25 from a junkyard.

 

Which pump? From what I can tell, there is two. One in the abs block assembly and one that the accumulator attaches to. I've never had it apart to really tell what is what. Only from limited view in the engine bay and pictures online.

SM-N960U ?

 

Mine was the one with the accumulator. I got a replacement from the local Pic a Part for basically chump change, bench tested it, took the old one out of my car, bench tested it (DOA) and used the one from the yard to replace it. Bled with a vacuum tool from Harbor Freight (used compressed air to create vacuum) and all was good. Didn't require techstream to bleed them either.

I will admit, I lost all the R134a doing the brake pump, tho. I have a vacuum pump and an a/c manifold for evacuating and refilling, tho.

 

I too have a vacumm pump and refrigerant manifold guages. maybe I'll take it as an opportunity to do maintenance on the ac system, see how much a new dryer, orrifice tube, pag oil, etc.

update: Did alittle online searching. Can get a Denso expansion valve for less than 30 bucks shipped, and a new desicant type dryer kit for under 20. so that with some psg oil and r134a should be all thats needed.


SM-N960U ?

 

Did this solve your issue? Im having the same problem.

 

Bob
I have the same problem with my car the ABS VSC is on and the brake are working fine how I can solve the problem

 

Hi,i have been following your post especially about the prius accumalator,my prius has almost the same problem,the C2156 code and the C2152 C2153,the low pressure from the accumalator,the rear breaks do not work,my accumalator os labeled "do not replace"and i have seen somewhere online that only a few percentage of cars that have sucha accumaltors that does not to be replaced,my question is ,what should be my next step?can i service or repair it?

Posted via the PriusChat mobile app.

 

Hi Bob, I know this thread is quite dated but I'm having a hard time finding info on this subject. I have a gen 1 with 133K and I started getting intermittent ABS/Brake light warnings (with a spongy brake pedal) a few months ago. the lights would always reset with a recycle of the system from Off to Ready. Yesterday they wouldn't turn off so I had to drive home with the spongy brake pedal. Now my problem is, where do I start with the troubleshooting? The fuses all look good but I have not tried to test the relays yet. On the Toyota wiring diagrams I only see a box labeled Hydraulic Booster. Are the pump and Accumulator in that box?

I'm stuck out here in Hawaii with no salvage yards to rescue me from the Toyota scalpers so any and all help would certainly be appreciated.

Thanks,

Ray

 

Sorry, it has been years since I was last in that area and it is miserable!

There is a difficult connector to reach to test the motor. You'll need to rig up a 12V 'jumper' to verify the hydraulic motor works. If it doesn't, replacing th part is extremely difficult. But if you don't have a salvage yard option, the replacement part cost will likely exceed the value of the car.

Bob Wilson

 

Hi Ray,

Do you have the trouble codes from the brake system yet?

If you read this post you will see that the car has a computer that monitors the operation of that motor very closely, and can give you a wealth of information just for the asking that would otherwise have you skinning your knuckles trying to reach difficult connectors to test.