Tacoma tries to kill me- fires brakes at random

I am so tired of chasing my tail with this truck. I have a ton of after market parts and it ride like crap. Any small bump in the road feels like the truck is going to rattle itself to death. Plus my taco is slowing trying to kill me. The brakes have fired at random a few times and I have no idea why (see below)...
Here is the build list:

OME bp-51s all around: spherical bearings replaced 6 moths ago
Icon tube uppers - delta joints replaced 6 months ago
Dirt King lowers- LBJs replaced multiple times. started with MOOGS and changed to Mevotech ttx and then replaced 2 times after that
Marlin crawler LCA braces welded in
Dirt king UCA double shear welded in
carrier bearing drop installed
LIL B's front bumper with winch
hooligan offroad made sliders- custom made
full RCI steel skids- front to back
fiber glass topper
topper ez lift system
decked drawers
OutGear solutions rear HC bumper with hooligan offroad custom swing out with a 35
Hooligan off road roof rack over the cab and cap
35" wildpeak AT
icon rebound pro wheels
Deaver stage 3 leafs
u bolt flip kit
sumo springs rear
duro bump fronts
archive garage hammer hangars
lil b's cab mount relocate
radiator mount and cab mount replaced with poly bushings
front arb locker
blaze offroad tuned
CV axles replaced with reman CJV reman axles with hd boots

When I'm driving around town any small bump feels like total crap. I have an appointment to take it to a shop in a week but if I can figure it out before then it would save me a bunch of money.

the other major problem is that every once in a while the brakes will fire out of no where. No warning, no repeatability, just out of the blue the brakes will just light me up and bring me to a complete stop. The VCS light comes on and will continue to fire the brakes- it sounds like the crawl control is on, but I am driving 35-55 MPH. I come to a stop, kill the truck, restart it and I can drive away normally, with no lights on the dash. This is obviously very unsafe and needs to be fixed. I have taken it to toytech and they checked my wheel speed sensors and gave the truck a once over and everything checked out just fine sensor wise. They found that the rear backer plate on the driver side is slightly bent and suggested: a backer plate, axle, bearing and all the goodies and seals that go with replacing the rear axle. I put a micro dial on the rear and the axle is not bent and rides true, but the backer is bent for sure. This could be the problem, throwing off the reading of the tone ring to the VSC, but I am not sure. Replacing all this will be over 2k and since the axle rides true and the backer place is the only thing that is bent I am not sold on the 2k replacement. I know I also need to do u joints because i have some vibration at highway speeds but its not terrible, but on the list as well. Its just really weird that I have not idea how or why it happens and cannot replicate it. I did have problems with my cab mount relocate bc the guy who did it melted some wires and they had to be cut out and re-soldered in place with new wires. The replacement wires were taken out one by one, and re-soldered and heat shrunk, one by one- from what i was told... who knows.

If you guys have any recommendations or experience with any similar problems - chime in

cheers

SB

 

The brake issue is definitely something with the master cylinder or wiring / being an off road / and the electronics . I know you have a lot of aftermarket stuff , but if you don’t get anywhere with your appointment I would say possibly go to a good dealer to see what this could be or really looking at the wiring diagram to the M/C . It’s something there for sure

 

I have been going through a similar issue kind of. I'll start by saying for about 3 weeks in January I was chasing down a short in the stop circuit. Found the short in front of the fuse box and was able to fix the short related problems.

Now for the similar issue. Mine would not let me brake when I needed to brake. Happened twice. Once on a highway off-ramp, I hit the brakes and the ABS kicks in stopping the pedal from going down, all the dash lights come up, you can hear the booster pumping sounds a little like grinding. No matter how hard you push it will not brake. I had to use the emergency brake and went off into the grass over a curb. Shut the truck off, started up with no issues, I turned Trac and VSC off, drove the back roads home with no issues. Chalked it up to being a fluke. A week later out of nowhere driving 45 no brakes again, had to take a right turn into a neighborhood at 40 slamming on the brakes and trying to use the E brake. Once I came to a stop, shut the truck off. Tried to start it and this time it would not start. Held it down, it started after a couple secs, the shifter was locked, unlocked it and limped it home with the abs/trac firing while I was driving straight. I was a mile from my house. I immediately started to test it out driving around my neighborhood with my scanner connected reading live data. Nothing unusual came up on the data, wheel speed sensors read the same speed, yaw rate, steering angle, master cylinder temp, master cylinder pressure all came back good within specs and working as expected.

The codes it was reading where --
P05042B -- Brake Switch A/B Signal Cross Coupled
C1425 -- Open in the Stop Switch Circuit

I had short circuit flashbacks and went right to the fuse. Pulled the fuse and it was good, not blown. Put a multi meter on it and noticed the feed side from the brake switch was jumping all over the place while the the other side was a solid reading same as the battery truck was running. I went right to inspect the switch.
While I was inspecting the brake switch I noticed the brake lights where not coming on till the pedal was almost half way down. I adjusted the switch so that they would come on sooner. Went back to the fuse, readings were still jumping so I swapped the fuse with another fuse, no more jumping. While I had the meter reading I wiggled/pulled the fix where the short was, the readings stayed solid. So that removed the short repair from the problem. I went for a test drive with no issues. No ABS lights, no brake warnings, and no brake override malfunctions. This was yesterday. I'm still not convinced its fully resolved.

Now, I did a ton of taking apart, pulling, cleaning, searching, unplugging, installing new parts, fuses, relays and putting everything back together while I was searching for the short.

A couple things I did do while I was putting everything back together.

I removed the resistors form the Meso tail lights and I installed a factory clock spring/steering wheel angle sensor. While I had the interior taken apart I noticed the clock spring/sensor where not factory. I did zero it out and calibrate it.

If you have resistors in the tail lights remove them, also check the stop fuse to see what it's reading on both sides, and check how much you have to press the brake pedal for the lights to come on. I would take an in depth look at the repaired wiring, and if you decide to change the fuse in the box try to find a factory fuse. With some of the cheap aftermarket fuses the blades are thinner which can cause a connection issue.

Tracking down issues that come and go is a pain, good luck. I hope it all works out. Keep us posted.

 

The brakes sound like u have a faulty collision camera that’s malfunctioning. Try unplugging it and clean the connector with some electronic cleaner .

 

As far as ride quality is concerned, you added a bunch of extra weight, poly bushings where soft rubber was used before, and coilovers that replaced bushings with bearings, the end result is an awesome truck that sucks to drive to/from work every day. If you want it to ride like it was stock, then leave it stock, don't throw money at the issue expecting a smooth comfortable ride, you'll end up broke with the same ride quality you have now, my advice would be to maybe have the coilovers tuned for your specific set-up if you haven't already. The braking issue could be any number of things, the change in ride height, dirty/faulty FCS components, or it could likely be related to whatever shorts were caused by the guy who welded in the Cab mounts.

Anecdotally, My stock 2019 off road will occasionally flash the red "BRAKE!" warning and beep at me but has yet to actuate the brakes unexpectedly, but that is a concern of mine that one day the truck will unexpectedly brake hard at highway speeds or at any other time where braking would lead to an accident. maybe find a good ADAS specialty shop to diagnose the issue if the dealer is of no help.

 

He has a 16. Thought that started in 18?

 

yep, definitely not a feature on 16s nor does it sound like that issue IMO.

 

Total crap means? Bouncy? Harsh? Squishy?
Where are your adjustable compression and rebound settings?
How many miles in them?
What are your tires wearing pattern?

 

The ECU is getting signals that makes it think you are sliding out of control. Multiple inputs involved. Here's from another TW thread:

 

This is most probably what the issue is, the truck thinks you're in a full skid.

If you really want a head scratcher all that data runs through the gauge cluster also. So if the cluster gets un plugged almost every computer takes a dump.

 

Right on - thanks for the comment. I don't trust my dealers around here, they have messed my truck up on 2 separate occasions. I haven't tried Mountain States yota yet but I hear they are far better than the dealer I originally went to. thanks again

 

Classy! thanks for the comment man- love your channel on YT. I will do some hunting and see what I can turn up. I am not the best at electrical so I will enlist a buddy and show him your post. Thanks for the comment and advice.

 

all the parts I threw at the truck were out of necessity- I broke, damaged or wore out components and replaced with aftermarket upgrades. I wheel the shit out of the truck and daily it. I guess I am not surprised that I have problems and can usually fix them on my own but since it is non- repeatable and happens out of the blue its really tough to DIAG. Plus its electrical which I really suck at. I will look into your suggestions. Thanks for the comment

 

bring a lighter and some beer and lets burn this bitch! j/k I will get it figured out sooner or later or you will never hear from me again bc the truck ends up in a guardrail or rear ended by a Semi on the highway bc the brakes fired out of no where.

I will look into your suggestions- thanks for the comment .

 

Feels harsh. Settings are on the soft/ slow side- kinda in the middle.

Miles- no idea. I got them used but rebuilt from ARB direct. Someone on here sold them while ARB was rebuilding them bc it was going to be 12 weeks for the rebuild so he bought new ones and sold me the old ones. ARB shipped them direct to me after rebuilt. Driver side is brand new after 4wp destroyed the bearing eye when they were pressing out the spherical bearings, this was about 3 months ago. Pass side is old but with fresh bearings.

tires are wearing normal

 

killer info here- I did have to replace my steering angle sensor a while back- that could be the culprit. I replaced it with NON OEM not knowing this is all tied together and I was being cheap. I might yank that out and stuff in an OEM. Thanks for the comment!

 

To chime in, it could also be a wire associated with the master cylinder that's chafed. Vibration/bouncing could cause it to move and short out randomly, or maybe just enough to trigger a response from the ecu. Definitely an aggravation pulling apart and inspecting wiring harnesses, but given that the wheel speed sensors are involved, I'd start at each wheel, then work your way back up to where they go through the firewall. If you had to pull parts of the dash for the steering column sensor, something could have been chafed/pulled while working under there- but it may be the non-oem sensor. Were you having this issue before that was replsced?

 

well after my harness got cooked from the cab mount relocate I had a handfull of issues. some evap stuff, steering angle sensor and a few others. After the wires were repaired the issues went away for a while. Then I had the brakes firing out of the blue issue. It all has to stem from the harness on the DS right above the cab mount getting cooked. it does make me think that there is a short somewhere because I didnt have an issue for a long time and then the day we got rain, the brake issue popped up. So some water bridged a connection somewhere and made everything freak out. I will dive into it and update to what I find. Thanks

 

Just to add to this for future searchers because it doesn't sound like your particular problem. When my brother lifted his truck he didn't notice his park brake cable was on a bind, this would cause the brake lock up and ABS sounds. Just going through a gutter or any slight articulation would cause the truck to lock up. I don't remember if any dash lights came on but it would beep like it does when it tries to correct itself from a slide. Something simple to check out too.

 

just to push back a little bit, I have an Icon Stage 8 kit and it rides 100000% better than the truck did stock.