Intermittent Brake Issue, TRD Off Road

Man your awesome thanks for that will be tons of help.

yes i have done the zero point many times it seems to eliminate the problem temporarily and other times it has no effect but i have not done it and monitored the accumulator and master cylinder pressures ill have to do that today and see if anything changes

also take your time no need to rush on the diagram just whenever you get some time

 

So i was doing some more research trying to learn myself some new knowledge lol... But i ran across a thread about guys having a similar issue as us and there saying it could be the VVT OCV solenoid and or the screens have you heard of this i checked my screens a few months ago and they were clean but did think of checking the solenoid... https://www.tacomaworld.com/threads/throttle-position-sensor-issue.355551/

 

I believe the guys in that thread are trying to address driveability issues and the solenoids they discuss are first the ones in the automatic transmission and later the thread focuses on the two solenoids that control the oil control valves and hence timing of the intake cam. It might be worth taking a harder look at the pin-outs to the hydraulic booster assembly ECU to see if there are any connects with the engine ECU. I do not currently have a driveability issue.

 

Yea im not a 100% sure what exactly my issue is there are times i think it could be transmission I was getting Lean codes there for a while replaced my canister and fixed a caccuum leak and hasnt been back but i do get random times my truck ticks really bad and loud then itll just go away randomly and startability codes sometimes

 

Is that startability code P1604 by any chance? If so, I created a thread on it sometime back. And yes, it get the code too on occasio, but it too has never sets a MIL.
https://www.tacomaworld.com/threads/code-p1604-strangest-code-ever.350182/
I tink the consensus on that code is to ignore. And I do. After all, TS pops up a dialog box that says "Do Not Diagnose"

Have you had anyone else look at the tick? If you do a search you will likely find that that one of the most common complaints with the V6 is the ticking. Mine has made the ticking noise since new but I went into the purchase knowing that most likely all tick to one extent or another. If you got a ton of miles you could also consider lash of the valve shims.

It certainly would not hurt to check operation and vigorously clean the VVT-i solenoids of the oil control valves and also pull their filter screens and replace with new or clean them extensively.

Take a look at your fuel trims on TS, both long-term and short term. I ended up replacing the intake gaskets, throttle body gasket, cleaned the TB super good, and also pulled the fuel injectors and sent them to be flow balanced. One injector was really bad so I replaced. I also replaced the MAF sensor. This all about 10k mi. back. It has run perfect since other than the hydraulic unit code...

 

Alright this is what i came up with while trying to bleed my brakes with TS started with the rear worked just fine both wheels went to activate the front passenger nothing happens, no fluid no sound so try again still nothing so i try the driver front same thing nothing happens press the pedal fluid comes out so not blocked line so found how to test the solenoids says to hold brake 15seconds activate solenoid and if pedal drops to replace “ABS Actuator” tested all the solenoids and two of them drop to the floor the SFLR AND SRRR solenoids which are the both front wheel… ill add the file of how to test… Now where are these solenoids located im guessing there internal power booster??? And im sure it isnt a cheap fix either..

 

@toytaco112

In 2014 I downloaded from the TIS site what appears to be a revised procedure for bleeding the brakes on models with the hydraulic booster. I use it and has been the most effective for me.

I will try to scan it this morning (they use a lot of different light colors for the text so cross your fingers) and send your way. At the very end of it all they then want you to use TS and individually bleed the fronts, with the bleeders closed, to route air up to the MC, and then bleed the rears, this time with alternating the bleeders open, to get rid of said air.

 

Gotcha that makes since i read that last night while reading up on the whole process trying to figure out what the deal was.. came to the conclusion that the solenoids were not my problem.. went to bleed then without that knowledge a d was fetting lots of air from tthe front obviously from me doing it wrong so going to try and do it again today the new and inproved way.. When I pull up my ABS History on TS infound 2 codes that were under system “BA” whatever that is and both for and when looking at data everything looked fine ill see if i can upload the data later and maybe i missed it or am looking at it wrong

 

@toytaco112

Here is the procedure for bleeding the hydraulic boost system that was revised in early 2014. It applies from 2009 to date of the revision and likely thru the 2015 model.
I had to scan at high resolution to capture the faint colors in TIS so it is readable.

IMPORTANT NOTE: If you review the work procedure box midway on page 1 you will note the procedure is divided into two parts depending on the part replaced:

1. Bleed Brake Line, beginning on page 1. This is for the replacement of a flex hose, disc cylinder or rear brake cylinder.

2. Bleed Brake System, beginning on page 2. This is for when a major component or sub assembly is replaced.

Tip and Gotchya: follow exactly what to do. Only open bleeder screws when it says to. It can be a bit confusing IMHO. For example, on page 2 of Part 2(n) this sentence appears:

"Repeatedly depress the brake pedal several times, and then with the brake pedal depressed, turn FR Line on and bleed air."

This should not be read to mean the the bleeder screw is opened to bleed the air. It is not. Rather, using the TS air is moved internally back to the master cylinder reservoir. A later step that applies to the rear brakes then removes said air from the system.

 

Thanks man ill give that a try and report back later tonight

 

Didnt get a chance to bleed the brakes yesterday using your notes, but I had done the old way I guess and truck has been driving normal now with a very very slight braking at certain times any normal person probably wouldnt even know it was doing it.. So my guess is when i did my brake system and replaced lines i just had alot of air in the lines and probably still have a little more.. Going to drive it another day or so and then bleed the brakes one more time using your notes and hopefully fingers crossed it stays good. Really appreciate all your knowledge and help.. Not many people that will do that nowadays.

 

Keep your eye on what the accumulator pressure is doing. I checked mine a few minutes ago and the code is gone....for now...but pressure still on the lower side of what is considered normal.

BTW, a few years ago I took a close look at the brake fluid following its addition to the reservoir. Sure enough micro-bubbles were present from the cascading of the fluid. Cold fluid seemed to be the worst and when warm the small bubbles would languish less. Now I try to use relatively warm fluid, pour slow, and will often wait for some time following additions before resuming bleeding.

Apparently those extremely small bubbles are very tenacious and like to cling to odd surfaces inside brake lines and other assorted places, and can be tough to break free. I even know guys that use a small hammer to tap on lines and calipers prior to bleeding to help dislodge tiny bubbles.

 

Been watching accumulator pressure and master cyl theybare exackly as before but dont fluctuate as much after bleeding the brakes and truck has been driving much better since

 

What about a transient code? Mine is gone....for now.

 

No codes that i know of will check today and let you know

 

Did you ever replace your master cylinder and or figure out what the problem was???

 

No, its sitting here all boxed up. Been preoccupied this summer so it looks like a winter project.

 

Sounds about right to do list but no time to do it in lol… let me know the results when you do swap it out

 

Shall do. In the interim I think I will get out the scan tool and see if that phantom code is gone.....or back. Still no CEL but that lurking code has to go.

 

No codes on my end but still getting that random feeling the brakes are on… Kind of weird when it happens i can hear that light rotor pad sound when they barely are touching each other, my steering gets a little stiffer, suspension feels like its bottomed out when hitting a bump.. Truck drifts right sometimes…. Fresh alignment 2 weeks ago…. Im lost on what else it could be….. cleaar memory using TS truck perfect for 2 days/ 60 miles or so then starts acting up or sometimes it is perfect for a week sometimes 2…..