Failed To Air Bleed brakes with Techstream

You can search for the procedures on here PC. There are some good brake jobs.
I have experienced similar issues with my tech stream too. What I do is after I'm done bleeding the front brakes as a conventional vehicle is done(by removing the abs motor relays to disable the rear brakes), I then reinstate the relays back, and bleed the rear.
Since the tech stream always gives an error of not being able to bleed the rear brakes, here's what you do.
1. Turn ignition to ON, not ready
2. Remove rear wheels, and place on jack stands
3. Have a help apply the brakes once to the floor
4. Use a 8mm socket to bleed the air out of the system by loosening the bleeder valve.
5. Do same for the other side, and you're done.
6. The rear brakes are always difficult, if not done well.

PS: always bleed brakes in the orientation recommended by your car.
Bleed FL>FR; RL>RR pattern.

 

Forget the tech stream. I have encoubtered such problems too, when it gets to that stage it says "failed".
You bleed the front brakes like a normal car.
1. Get a helper, and have him pump the brake pedal several times.
2. While you're at the front, locate the bleed nipple, and ask your helper to press the pedal to the floor, and hold it there.
3. Use an 8mm socket or spanner to loosened the bleed valve, until the air bubbles in system comes out.
4. Do this procedure several times with your helper until no air in the system.
5. Clear the lights kit up on the dashboard, and you're done.
6. Remember to always have enough brake fluids in the reservoir before and after bleeding.

 

Hi ,

It seems as if you're kind of ignoring what the car is telling you. It is not able to hold pressure, because there is a leak within your brake actuator. This does not have to be an external leak, where fluid escapes and you find it outside the car. It is more likely an internal leak, where one of the valves in the actuator is not closing completely, and fluid is leaking from the pressure accumulator back to the reservoir.

There's no point in putting off replacement of the actuator until you can successfully bleed the busted one. That isn't going to happen. Better to go ahead, put a working one in, then bleed that.

-Chap

 

Great. Keep us posted on your fix though.

 

Yes, do keep us posted. And if you have a code come back, it is helpful to post the actual code—a letter and four following characters—which I don't see has been posted yet in this thread. The little one-liner descriptions you've been using might come up on the scan tool next to the code, but it's important to remember those are not complete explanations of what the code means and will often misdirect you. The best understanding of the situation comes from looking up the actual code's workup section in the manual.

-Chap

 

Since you already have another pump why don’t you change it out and then try to bleed the brakes? It’s free and if the pump is the problem you will know.

 

No matter what you do, that actuator must be replaced. It seems like you like trying unrelated things, despite the obvious signs that the actuator of the brake isn't OK.
Replace that abs pump! Don't keep wasting your time.

 

A few points:

1. You have a Gen 2 Prius, so the pump is not anything you can separately replace anyway. In that generation, it is part of the brake actuator assembly, which is also where all of the solenoids and pressure sensors you may be thinking of are. You might, for intellectual reasons, be curious about further fault tracing down to one of those pieces, but in any case you fix it by replacing the assembly.

2. Diagnostic codes have "detecting conditions" that are laid out in the manual in more detail than you might think. Even a code that has "pump" in the little fortune-cookie line that might show up on a code reader or in google, is not necessarily specifically about the pump. It's about the computer noticing something odd about the expected results of running the pump, which could turn out to be a sticky solenoid, wiring issue, etc. That is, a lot of the questions you're asking (and, better yet, the steps to answer them) are already written into the workup for the code, as you'd find out if you looked it up in the manual.

3. There is another resource called the "New Car Features Manual", which is separate from the Repair Manual but available the same way. It's the place to find the basic overview of any system in the car, diagram of the parts, what it's there to do, and how it does that. You're asking a lot of questions of the form "well, if X were the problem, wouldn't the behavior be Y?" and those kinds of questions are very valuable in diagnosis, so it's good you're thinking that way. But for those kinds of questions to really help you, you can't be pulling them out of the air; you need to have the diagrams in front of you so when you're asking "wouldn't X really have Y effect", you are honestly looking at the system in question to see if it would have that effect or not. And when you do that, those sorts of questions can lead you very quickly to solving the issue.

-Chap

 

Well, it's not so much a matter of "easier", it's that you already have troubleshot as far as it's practical to go. Any further troubleshooting would be about actuator assembly subcomponents that you can't buy. Were you thinking to take one apart and repair it? It would be worth posting about such a project ... so far I am unaware of any success reports (or even attempt reports) of that on PriusChat.

And if you really wanted to be the first to try to disassemble and repair an ABS actuator and then trust your safety to it, more time spent with the manuals would definitely be in order.

On the other hand, replacing it should not be too daunting, as long as you're up to the rather lengthy steps of getting to it. I do not believe it has to be "reprogrammed". You might use Techstream to check the firmware version of any that you put in, just to see if it's the latest. I don't know if I would ever try to reflash one using a cheap dongle; that might be a step best left for a dealer visit, where they have the official Drew Technologies one.

Cover all the brake line ends (with plastic!) immediately after disconnecting; similarly protect the ports of the replacement actuator until ready to connect the lines. Avoid any fabric gloves, shop rags, etc,, that could shed small fibers.

The Techstream bleed procedure (the longer one for "after actuator replaced", if it gives you a choice) will be the best way to get everything set after the replacement is installed.

-Chap

 

I was wondering if someone could lend me some advice (PLEASE) on a similar issue but with the exact same codes (C1252, C1256)? I am working on an '05 that had blown the 25 amp ABS-1 fuse and also the ABS-2 soldered fusable link. I replaced those and had the same problem so I replaced the abs actuator pump assy. (twice), the skid control ecu and the four abs relays and bled the brakes twice. The reason I replaced the abs relays is because the whole time there has been a recurring clicking noise coming from what seems like one or both relays. I've also tried the obd pin method to clear the codes several times. Any help or advice on what steps I can take to find the problem would be greatly appreciated! Thank you.

 

So I'm in a similar position. I have an 08 prius .I changed the drum brakes and in the process let the fluid out of the cylinders. I got the brakes back on and drums. If I bleed the back brakes only will thatthat be
the fix

 

How did the dealer repair go and what was wrong with your repair attempt? I have the same error codes and am planning my repair and am learning a great deal from your experience.