Traction control

The lift isn't hurting anything since the truck has zero idea anything is different. Still seems like steering sensor and most likely it was jacked up during the alignment somehow. Techstream isn't going to "tell" you but it'll let you read the important signals (steering angle, accels, yaw rate) to determine what's not making sense.

Toyota didn't understand your problem and take a deep dive. I'd first look for a drop out in your steering sensor going lock to lock and then double check calibration zeroes and that the yaw sensor reads reasonably. If it's not any of that then back to the drawing board.

 

Thank you very much. As soon as I can get techstream. Hopefully get it working at home I will post the results. Till then I’m gonna drive with auto lsd on since that’s quick easy press rather than holding trac off. With auto lsd I’m not having those traction control flashing or breaks engage

 

Yes, remember it's VSC that's your problem, not TRAC. Turning on auto LSD turns off VSC from 0-30 mph.

Something else that would go along with the steering sensor signal theory that you should check since you did do a lift and alignment is the mechanical parts of the steering system. Check the rack, bushings, tie rods, etc for slop. Have someone turn the wheel while you're under the truck and see if you notice excessive movement or play. Extra slop could be causing the system to see "excessive" steering input for the measured yaw rate and speed.

Another odd question. When VSC intervenes can you tell if it brakes an inside or outside wheel?

 

Yep i know. Was just curious since it was a downpour and when iv'e used auto lsd before i could break traction and flash the traction control light. But i guess thats just using the brakes to act like a limited slip. Its still all new to me. As soon as i can get someone to help i will check the components for slop. Thanks.

As far as which wheel gets the brake applied. I wouldnt have a clue. Lots of times just normal 90 degree turns only the light will flash from the vsc or i feel a loss of power till the light shuts off. When i pull into the parking lot i'm typically not on the gas just coasting in and the breaks pulse grind while engaging.

 

SAS seems like the most likely culprit. Scope the signal and then recreate the conditions. You should see something funky.

 

You got it. So when you break traction with auto LSD turned on the corrective action by the truck is braking the slipping wheel and not engine cut as that's the purpose of auto LSD, to not use engine cut for recovery of a slipping wheel (like a traditional LSD would work). The light flashes because the auto LSD system is doing its thing and that is proper function of the traction control system.

I'm definitely now leaning a little towards checking the play in your steering system before thinking the steering sensor is not working right. The sensor would be an uncommon failure from my experience but still entirely possible. At least play in the steering is a simpler fix and likely a cheaper fix.

Techstream will still help with all this, but you may end up needing another truck for comparison purposes if nothing jumps out as obvious.

 

Awesome thank you guys i will see if i can find anything or get assistance. My cable to try and load techstream is supposed to be here today as well.

 

You can't traditionally scope it because the steering angle sensor outputs steering angle over the CAN bus so unless you sniff the CAN bus, know the message ID, and know the conversion to engineering units you won't get anywhere. That's where techstream comes in.

 

Sorry, meant 'meter' not 'scope' I haven't looked at an SAS on one of these, isn't it a voltage output? You should be able to watch that and see a drop/spike in signal voltage if the sensor is dicky.

 

Negative, not a voltage output from the sensor. The spiral cable assembly (steering angle sensor) outputs a message on the CAN bus indicating its sensed position.

 

Ahhh... okay, disregard, not going to be a practical DIY approach, but a bi-directional scan tool should allow you to read the SAS data stream and spot any glitches.

You could also scope it just to make sure the network data stream looks viable.

 

Very hard to record in a parking lot steady but I got some details. The steering angle sensor is or seems to be reading correct. All values for yaw and steering were zero when sitting still. I drove circles in the parking lot till I got the light to kick on. Hard to tell but like mentioned. Around 360 degrees of steering while accelerating and I was only going 7 to 10 mph the light kicked on. The yaw rate was 30 to 40 degrees. One of the pictures I snapped because it was a right turn into the parking lot and a split second the left from wheel traction engaged.

 

This is an interesting thread, hope you find a solution. Being a tech my self (I specialize in European cars unfortunately) I feel your pain. These are the types of things I deal with regularly. Like previously stated you might need to hook up with another Tacoma owner and compare sensor data. The sucky part of not having any codes is what ever data or inputs the system is currently getting is seen as “valid data”, so as far as the car is concerned everything is functioning fine.

Sorry if this has been mentioned or already checked but make sure the ABS sensors aren’t dirty, make sure they aren’t loose and maybe check the yaw rate sensor and make sure thats not physically lose either. I hate to admit I don’t even know where the yaw rate sensor is located on our trucks but I’ve seen on the vehicles I’m familiar with where they’re mounted under the back seat or under the center console and the 6mm bolt backed off and the damn thing is producing erratic data.

 

Joined this community due to this same phenomena happening with my truck. @Teal_6, what’s the latest on your search?

 

Still currently hunting. Since then I’ve added a speed calibration unit. Which really didn’t help that I could tell besides correct my speedometer. Really didn’t expect it to help the problem. I did find that the lift shop installed a sway bar relocation kit. I removed the kit and still just barely had clearance. This seemed to help. Next week I’m gonna try and get more caster since currently I’m at 1.5 degrees on stock components. My belief is that it’s the yaw sensor and I’m getting too much body roll. The alignment shop said that due to the low caster on the lift which makes it very twitchy responsive steering It could be tripping yaw. Fixing the sway bar helped affirm this theory. When I ran techstream, all the times the traction control flashed while doing circles in the parking lot or turning to merge into traffic my steering angle was around 360 and the yaw angle was. 30 plus degrees

 

Not sure if you found this thread, but yaw sensor recalibration or a custom approach at the end were mentioned.

https://www.tacomaworld.com/threads/traction-control.475324/

In case it could be any help, my situation is as follows. 2009 TRD Sport dbl cab 4WD. 3” front and 1” rear spring lift (mall crawler), 285/70/17 Pro Comps on Icon Compression wheels. No sway bar relocation kit. The issue only occurs above 30-35 mph when turning right on twisty roads. Grinding noise, pushing the truck in a straight direction, and noise/alarm. I haven’t noticed power cut, but it could be occurring.

What is interesting is, when slightly turning left on a mild downslope, all road noise and vibration at the wheel goes away.

 

Thanks. Yep I believe I’ve seen it. Done the manual calibration probably 5 times and techstream vsc calibration a couple times and still didn’t help

 

Why is it folks modify a pretty well engineered suspension system the gripe when problems like this arise?

 

Funny how that works

 

Because this seems to not be a normal easy problem especially when many Toyota dealers sell the trucks with the little bit of lift I’ve done. But thanks