I have a 2011 ls 460. it did have the actuator replaced. I do have the 4 abs, vsc, check engine, slip lights. the lights periodically go off. it does show code 1256. brakes are soft but stop fine. been doing this for 5 months. any advice on fix would be appreciated! do i need to have brakes bled?

 

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Regarding your question if it is true that the VSC message shows up when the brake actuator is bad, my answer is yes. A bad brake actuator always tiggers the error code(s). However, the soft brake may not necessarily indicate a bad brake actuator. It could be that that the brake system has air in it and needs a brake bleeding. It's difficult for me to comment on the ugly noise you heard because I need to hear it before I can offer valid suggestions. My overall recommendation is that, if you are not a DIYer, skip this car because the ugly noise coming from underneath the car could mean bad suspension components, which will cost money to repair by the dealer or an indy shop, in addition to the cost for replacing the brake actuator. On the other hand, if you are a DIYer and can do the work yourself, and if the rest of car is in good shape at the right price point, the cost for replacing the brake actuator and the suspension components is reasonable. A new brake actuator costs about $1200. A set of non-OEM control arms costs a few hundred dollars.
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Code C1256 usually indicates a problem with the brake actuator pressure sensor. A 2011 LS460 is still within Lexus warranty for the brake actuator. You should take advantage of Lexus warranty and have your actuator checked and replaced by the dealer free of charge.
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yyymmm I ordered a brake assembly from feebay. It included the motor assy and the actuator. Supposedly it has a 30 day refund / 90 day warranty. For what I bought it for I wouldn't be terribly upset if only the motor is good. I should have a chance to install in on Wednesday. I'm sure I'll be back with questions

Regarding the pressure voltage reading the only one I was familiar with in techstream was the accumulator sensor it was .56v
Is it one on this page you were referring to? I'd like to check the voltage before I remove the actuator.

 

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A guaranty of 30 days of refund is a good deal in the event that it is doesn't work. What brake actuator part number is on your brake assembly? Yes, you are correct that your Techstream screen shot shows that your accumulator pressure output from the brake actuator is 0.56 volts, which is outside of the normal brake accumulator pressure range. Earlier, I mentioned that the normal range for brake accumulator should be 3.2-4.0V. However, recently, I came across a service manual for LS460, which says that for early models of LS460 (2007-2009), the normal brake accumulator pressure output range should be 2.6-3.8 volts. I'd greatly appreciate if someone on the forum could help clarify it. In any case, your accumulator's 0.56V output indicates that your brake actuator is not normal. After you have replaced the brake actuator assembly, check if your accumulator pressure output voltage is in normal range. You could also test if there is any leak on the brake actuator assembly lines by the following steps:

1. Connect your Techstream to your car
2. Turn the engine to "On" position (not to start the engine)
3. Read the accumulator pressure output (it should be in the normal range)
4. Then, depress your brake 4-5 times
5. With your foot off the brake and when the accumulator motor stops, check your brake accumulator pressure output voltage

If your accumulator pressure doesn't drop more than 0.2 volts, there is no leak and you did a good job.
Please keep us posted about your outcomes. Good luck.
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Here you go.

 

Ok! This is what I am dealing with and I believe you hit on the answer. I took to Lexus and they said code 1256 was brake pump assembly and not actuator. Is the brake pressure system sensor a separate or part of the actuator? That will give me the firepower to argue over the fix. they said it 2 different systems and this part, they dont consider part of the actuator! Thank you so much for the valuable information!

 

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Since your 2011 LS460 brake actuator assembly is still under Lexus 10-year special warranty, you may try to press your dealer to replace the actuator assembly under the warranty. Technically, the brake booster pump has a separate part number (47070-50040) from the brake actuator.
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[QUOTE=yyymmm31;10734150]----
Code C1256 usually indicates a problem with the brake actuator pressure sensor. A 2011 LS460 is still within Lexus warranty for the brake actuator. You should take advantage of Lexus warranty and have your actuator checked and replaced by the dealer free of charge.
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Thank you again for your advice and help! Regarding the accumulator, the brakes seem to work fine. Is the ABS completely disabled? If so, does it do any damage to car while driving with light on? I may be working on Lexus for awhile and plan on driving it in the interim!

 

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Since your dash intermittently displays the ABS/VSC warning message and you periodically have Code C1256, I think that your brake actuator pressure senor has some problem from time to time but the problem is not constant. Based on your description that your brake system appears to be working fine, I think that your ABS is working. I don't think that your intermittent brake actuator sensor problem will damage your car. If and when you have a constant brake actuator problem, your dash will flash with warning messages and your brake will feel heavy and will function abnormally. In my opinion, you should try your best to have the brake actuator sensor problem solved by your dealer under the Lexus special brake actuator warranty. Usually, Lexus dealers are pretty responsive to reports of brake problems because the brake system plays a critical safety function. With or without warranty, your dealer should fix the problem.
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I installed the used one I purchased today. Everything seems to be functioning as it should aside from an intermittent bark / squawk noise. No codes, no lights. More importantly the brakes now work

I do have a few questions about the brake bleed process. I want to use motor pressure to bleed the front brakes. Can I just crack the front bleeders one at a time with the car running and brake pressed to accomplish this?

I used this tutorial when I replaced the actuator and motor assembly. I followed the steps as they were written.Technical Service Bulletin # SB0069-09

Date: 090602

Brakes - Squawk Noise From The Brake Actuator

L-SB-0069-09




It instructs to manually bleed the front brakes. The back brakes it instructs to use the motor system pressure to pump fluid out the bleeder ports. I'm guessing with my intermittent noise I still have some air trapped in the front brakes. I feel like using the motor pressure method to bleed the brakes works better at pumping out the air bubbles the flow rate is a lot faster. Is there some trick to getting the flow rate up when manually pushing the brake pedal to bleed the front brakes? How many times do you typically push the brake pedal for each wheel?

UPDATE:... It's not making any abnormal noises anymore. Crossing my fingers the silence lasts. Thanks again for your help yyymmm31 !

Another update 4-1-20 It is still working fine, no noises. The ebay seller offered to extend the warranty another 30 days if I left a positive review, pretty cool.

 

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Congratulations on your successfully replacing the actuator/pump assembly and fixing the brake problem. Regarding your question about power (engine-on) bleeding of front brakes, I have always adhered to Lexus brake service instruction and bled LS460 front brakes manually after zero-downing the pump. Personally, I wouldn't recommend "power-bleeding" the front brakes. If you feel there is still air in the front brake linings or calibers, I'd just keep manually bleeding until there is no air bubbles coming out and until the brake fluid is clear. In my experience, the manual bleeding of front brakes on LS460 always worked and made front brakes solid and responsive. Just make sure that you zero-down the pump before manually bleeding the front brakes. I fear that power-bleeding (with engine on and without releasing/zero-downing the pressure in the pump) may damage the brake actuator or pump. Also, make sure that your car battery is fully charged whenever you bleed the back brakes as the process consumes a lot of battery energy. BTW, what is the part number of your brake actuator?
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Thank you. The ebay actuator I installed was an old version. p/n 44510-50070 I've put about 50 miles on it. The majority of the time it is silent, every once in a while I get a slight noise. My 2007 does the same thing. I've been sucking out the brake fluid in the reservoir and replacing it when I do my oil changes. Hopefully that prolongs it's life.


. I had to swap the 90 degree plastic fitting from my old actuator onto the ebay one. There is a small screen filter behind that fitting. I'm curious if those who have found the white debris clogging their actuators had any debris in that screen. Both of my screens were clean. It would be neat if someone determined a chemical that would break down the white debris without damaging the internal seals. Maybe something like CLR could be used to flush the actuator. I think clr is water based...Trying to flush the clr water out of the brake lines might not be worth the risk.

 

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Thank you for the information about the actuator part number. That's the original part number on most of 2007-09 LS460's and is the same part number on my LS460. You have gone beyond and ahead of me with the brake actuator. I have not attempted to take it apart and repair it. I think that regular brake fluid change/bleeding every three years is a good preventative measure and can help extend the lifespan of the actuator.
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Thanks to this forum I discovered the extended warranty, went to the dealership and had the actuator replaced on my 2011 LS460 L with 120.000+ miles. Try that with your Mercedes, or almost any other make...