'06 DC VSC system

So now that winter finally hit here, I've gotten the chance to play with my '06 DC in the snow and ice, and have noticed a few things that I'd like clarification on. When I first got this truck, I was comfortable knowing that the VSC would kick in on winding mountain roads, especially if the road surface had any grit on it. But now after a few days in the snow and ice, and the system showing its face more, I'm wondering how all of the different lights play together? For instance, during the summer on the mtn roads, the slippery tire symbol, the VSC symbol, and the ABS symbol would flash and you'd hear the nannies beeping, but the brakes wouldn't pulse unless it was a fast enough turn. Now in the snow, I can get the slippery tire to come on flashing, with NO beeping, the brakes engage and throttle cuts, which seems like it's doing as it should, but here's what I'm wondering.. during the first start of the day, when pulling out, the ABS, VSC, and slippery tire symbols will come on solid, there's no beeping or activation of the brakes, or fuel cut off, and the symbols just stay on solid until the truck is shut off and re started. Does this sound separate from how the system is supposed to function when its actually engaged? Is this signifying an issue with the system? No codes are thrown on a regular code reader, and it doesn't seem like its acting unusually, I'm just confused why the lights come on solid when the system doesn't actually engage or sense slip, and why they flash, but don't beep everytime? Can anyone elaborate on the difference between how these lights and beeps play together? I've been reading alot about it, but it's still a little unclear.. thanks in advance.

 

I'm going to ask this, and not in a snarky way, but have you read your owner's manual? You can download a copy online directly from Toyota for free. I know it's, a crazy place to start and all.

 

I've read the "owners manual" in my glovebox, yes, and really all I got from it was, "contact Toyota". Lol
The "service manual" pdf is 5,000 pages long, and I've been looking in there but haven't found anything yet.
This was the chart I was thinking of though..

 

I think in order for it to start audibly beeping, the truck needs to be acutely sliding. The Yaw sensor would then activate the beeping and braking. At least that’s how it was in both my little scion xB And my friend’s tacoma. I found that VSC was truly a frightening system. It would automatically apply the brakes and cut the power. I think it was purposely designed to crash out a vehicle? Sort of…well exactly like toyota having job security.

 

Okay some new info..
Friday night I was driving out of my neighborhood, and while going straight, my wheel was at 90° from center. I thought I was tripping out, so I got out and looked thinking I had a broken tie rod. I restarted the truck, the lights went away, and I continued on with the steering feeling funny, but no other events. This morning, my partner experienced the same thing just a few minutes ago. She was driving straight, the lights all came on, and she had to keep the wheel 90° to the right, in order to keep the wheels going straight. She shut the truck off, the lights went away, then it Happened again a few minutes later. Same thing, turn it off and back on, lights are gone, steering feels normal. Something is majorly wrong..
Any ideas what is going on here?

 

I’m wondering if it could be a yaw sensor, steering position, or clock spring. Has any work been done to the steering wheel or steering column?

 

The only things I've done to it since I got it last spring was put bilstein 5100's up front ,on the 4th notch, with the stock springs, and went one size up in tires (265/70/17), got an alignment (a shop that does lots of custom Toyota's), and changed the plugs and coils. I haven't done a zero point calibration yet, since I haven't had any issues until the last few days, but maybe that's my next move. What's getting me is the ABS VSC lights coming on solid from the first take off after the truck has been started, even with no slipping. They stay on solid until its shut off, so that makes me think there's something else going on other than the usual functions of the system. This doesn't happen everytime, and there's no pattern to it that I observe. When the steering wheel went 90° while still moving straight, I thought it was in my head until it did it again this morning, twice in a row on dry pavement. Then I knew something is definitely wrong. It stayed that way until the truck was stopped and was shut off. Then once restarted, steering returned to normal, only to do the same thing again minutes later.
I just crawled under it and checked everything visually. Wheel speed sensor wires look good, no broken u bolts on the rear axle, tie rods feel good, etc. I'm reluctant to pull the wheel speed sensors until I soak them with PB for a few nights. They are sealed on there good! The only other things I can think of are bad steering rack bushings, and that I've had a front caliper pulling to the left recently when braking hard. Maybe that has something to do with it? The other thought is maybe a mouse got into my center console and got the yaw sensor wires. Disregarding the dash lights, what would make the steering wheel go 90° while going straight? I know this is a little confusing so hopefully I'm getting my point across.

 

Any play in the steering rack? Crawl under and watch while someone steers back & forth.

 

When this happens, the ABS, VSC, and slippery symbols come on solid, there's no flashing or beeping, the brakes do NOT engage, and the throttle is NOT cut. Those things DO happen when the vehicle is ACTUALLY slipping, and everything seems to function normally then, but I feel there's another issue creeping around with the lights staying solid when there's no slipping. But then there's this 90° steering wheel effect I don't understand..
For now I disconnected the connector on the front of the master cylinder next to the ABS module to turn off the VSC. That should at least be a temporary solution? I know the VSC system ties into alot of other systems so it's a little much to absorb.

 

Not really any noticeable play with the steering rack. The first time it happened I went under while my partner turned the wheel and I didn't see anything unusual. The bushings do look pretty crusty tho, and I have a set of new poly ones I didn't use on my AC, but I know VSC doesn't play well with poly rack bushings, so I probably have to hunt down OEM, and you can only get them when you buy a new rack.

 

Is it possible to jumper the obd2 connector to read VSC codes like you can on a sequoia?

https://youtu.be/KfKsaxzbT1I?si=CwgaWcGig7s5ZJTa

 

The entire steering system on our tundras is 100% mechanically engaged system at all times. So there’s no electric steering, no rubber steering rack belts. Just plain ol’ steel on steel. So if the steering wheel randomly reclocks itself 90 degrees off center sometimes, then randomly reclocks itself back to center at other times, then there are only so many things that can cause that.

- Either the roads are super slippery and you don’t realize that the steering wheel is turned.

-the clamp on the steering column shaft got so loose that somehow the splined fitment is stripping out.

-the teeth on either the rack or pinion gears are stripping out.

-the jam nuts on the tie rods have backed off, allowing the tie rod to loosen up and become unthreaded a bit.

-someone hit a curb and bent a tie rod end.

-somebody at some point swapped out your good bushings for rotted out rack and pinion bushings that already had 900,000 miles on them.

-somebody in the past didn’t install that really thick oversized washer in the correct position on the rack and pinion bushing.

I grab your partner, dosey doe and go back under the truck for a second looksee. Have the key in the ACC position, but don’t start the engine. Turn the steering wheel slowly back and forth, from lock to lock and look for any telltale signs of inconsistencies. Bring a flashlight and possibly a tape measure. Do it on dry ground so that you don’t feel rushed to quickly get back out from underneath…as in, spend as much time as it takes to find the problem.

 

Okay thank you. That was more of what Info I was hoping to hear. I'll go back under and re-check everything and report back. I also feel like the only way for that to happen is for a psychical mechanical problem that I'm not seeing, and the VSC codes are a symptom of It. The lights staying solid these last few days might have been a warning before this actually happened. It would make sense to me that the column splines or the rack gears stripping could be the culprit.
The steering has always felt really good and buttery, unlike my AC that barely feels like had power steering.

 

What sort of cryptic BS decoder did some Toyota engineer design here?

Must be an analog guy…they tend to pull crap like this. I’ve seen it first hand.

They need to stay on their side of the fence.

 

This is pretty much what the tundra steering system looks like. Look for missing or backed off nuts or bolts in any spot where things are clamped down.

 

While I may not have your same issue with the VSC lights, I was having the steering doing weird stuff and feeling unsafe. Had the wife do some steering wheel maneuvers while I watched every joint under the truck, and it revealed several things for me. Namely I saw my entire steering rack shift almost a full inch off center each time she turned the wheel, and even more so at full lock. Also I noticed some concerning movement in the tie rod joints, mostly on the driver's side. My steering wheel would be turned almost 90 degrees like you described just to keep the truck straight either in the neighborhood or on the hwy. Felt like I had no alignment and the truck would pull to the right or it would "wonder" in the lane on the hwy, and me having to make exaggerated steering corrections.

I started with the rack bushings and replaced them with the red poly bushings from energy suspension (and coated them with copious amounts of silicon grease). Night and day difference in the steering performance and feedback.

With your VSC lights and all, I would wonder if you have a bad/dirty sensor somewhere on one of the wheels. I recall watching a video on youtube about a guy who was having problems with his VSC system causing dangerous counter measures unexpectedly on mountain roads. He had the big "unicorn" electronic brake booster with the integrated ABS module. He rigged up a toggle switch to the VSC plug on the ABS module and made the problem go away. The lights stayed on, indicating the system not functioning, but he did not have the dangerous counter steering. I can't find the video but it was alarming to watch when he demonstrated while driving.

I will also add, my traction control and VSC light come on when the check engine light is triggered. I have an O2 sensor that "is slow to respond" according to the Toyota tech that ran a diagnosis on the truck before I bought it (toyota service records say the sensors were replaced, but did not fix the issue, tech notes recommended tracing the O2 wire harness for issues but previous owner declined in leu of replacing sensors). Every once in a while it will cause the CEL to come on, and along with it the VSC and traction light, I will plug my hand scanner in, erase the O2 code and all the lights turn off til the next time, which is maybe 5 times since I've had the truck.

 

Yes I do believe I have the "unicorn" brake booster/ ABS module! And I did watch the video you mentioned earlier today. I'm fine with driving around with the connector unplugged, it just sucks we can't turn the system off with a button like the sequoia or 2nd gens, and we have to live with the annoying dash lights. If I knew more about the issues with the system at the time, I might have not bought this particular truck.
As for steering rack bushings, I do have a brand new set of the same energy suspension poly bushings you're talking about, but I thought people had reported having worse VSC sensitivity issues with them, so I haven't put them in yet.
And how you describe the feeling of "losing alignment", that's why I thought initially I had broken a tie rod or something.
I will update more tomorrow after I spend some time underneath.

 

I’ve never heard of having poly rack bushings causing worse VSC sensitivity. I have heard of reports of poly bushings causing more vibrations when they were used for engine mounts (in completely other 4x4 applications though). I’d definitely install those new poly rack bushings that you have.

 

I have not heard that either. I haven't had any issues like that since replacing the three bushing on the steering rack. Only issues I hear of are the squeaking if you don't use the correct grease.

I would start with mechanical function of the steering, checking for issues along that, also hook up a little scanner and just see if there are any codes that could be triggering your dash lights (it's the easiest thing to look at). My 00' tundra CEL bulb went out back when I had it. It had several codes, but ignorance is bliss I suppose. Maybe your CEL isn't coming on but something else is triggering it that might show up as a diagnostic code.

 

So update, I was just able to get the problem to return without triggering the VSC codes by going extra slow through my neighborhood. Now it's consistently off 45° to the right, it's never gone to the left (the first few times seemed worse at 90°).
No codes are coming up on the obd2 with a regular code reader. The check engine light definitely works, as it function checks when you turn the key on. I was looking into how to test for ABS codes like the sequoia by jumpering the contacts in the obd2 connector and counting the flashes on the dash to see if that gives me any other clues.
This sounds like what whodatschrome said, a bad stripped out rack, or the intermediate shaft splines. I'll be under it here soon to look more.

 

Process of elimination. On to the next....

 

Okay I spent all afternoon under it trying all kinds of different things, I think I finally figured it out..
It was a loose passenger rear control arm bolt! The whole rear part of the arm would slop around changing alignment at random. It all makes sense now.
I had an alignment done a few months ago when I got new tires, and I knew I should have double checked they torqued all the cam bolts. I feel a little silly I didn't see it sooner. Whoever did the lower control arms last was lazy and didn't wanna move the steering rack out of the way to put the rear cam bolt in, so they put them in backwards (from the front). This shredded the steering rack boots.
I'm planning on doing the steering rack bushings soon anyway, they were really crusty, but had no movement. They're gonna be a nightmare to get out. Maybe torch?
I'll also be redoing the LBJs and LCAs with OEM (currently moog from previous owner) with JBA UCAs and ome coils as well.
Thanks everyone for sticking it out with me! I appreciate the kind feedback and wealth of knowledge here on the forum.

 

eeesh, that'll do it