Vehicle Skid Control (VSC) Extremely Sensitive (Advanced Troubleshooting)

Background: I have had the Truck for over 5 years and I have never had a problem with VSC. I could take turns very aggressively and it would only come on when the tires were about to break loose. The only exception is tight mountain roads, it seems to get more sensitive if I'm going up or down hills and take a tight curve. I've had many different suspension setups and different tire sizes. The system has always been the same, never changes. It works very well, especially off road where it has saved my ass more times than I can count.

Current situation: Ok, so @papasmurf and pulled my steering rack to fix the mounts and then replace the bushings. We disconnected the worm gear box at the rack (bottom of the steering shaft were it meets the rack). We measured and tried to get it centered, but of course, when we re-installed everything my steering wheel was cocked 90 degrees. When I drove it home, my VSC was going crazy on the slightest curves. I took it to an alignment shop and they aligned it and clocked the steering wheel. I assume they adjusted it at the intermediate shaft connection. Afterwards there was no change, VSC is still excessively sensitive. the slightest curves will set it off. Even if I stop and make a right hand turn, like at a stoplight, it will go off.

Then I connected Techstream and found two history codes, one for Steering Angle and another for Rear Speed Sensor (I broke a wire several months ago and repaired it). I checked the Data List for the VSC and I found my Steering Angle Sensor was -24 degrees and my Steering Angle Value was -370 degrees when my steering wheel was centered.

As per the TSB, I did a Zero Point Calibration Data Clearance, a Deceleration Sensor Zero Point Calibration, and finally a Perform Initialization of Steering Angle Sensor. Afterwards, everything was 0.0 except Steering Angle Value, which was 1.5. The Yaw sensor and G sensors, everything was 0.0. The history codes were cleared. However, the VSC sensitivity did not change.

I brought it back to the alignment shop (btw, this is not a normal alignment shop, they do high level work on big trucks RVs and custom/classic cars) and they checked it with their scanning equipment. Everything looked normal and they tried another zero point calibration, but its still sensitive.

Speculate: Let me start off by saying that I am not going to shim the yaw sensor. That is the dumbest idea I have ever heard of. If the sensor is not level because of a lift or whatever, then zero it out and it will read level.

It is possible that my clock spring is 360 degrees off. However, I thought if that happened then it would break and I wouldn't be able to read steering angle? If it was off 360, but not broken, then its reading zero now so shouldn't it be good to go?

I do not have any codes or trouble lights showing. No history codes either.

Is it possible that the system does not like to be level? Maybe I should jack up the rear or the front, then level it so that I'm driving normally with like, say 1.0 or 2.0 degrees plus or minus?

That is literally all the ideas I have. I thought about taking it to the dealer, but I am not sure what else they would do besides a Zero Point. And I do not want to gamble and pay them to experiment.

I know there are some smart guys on this forum that do deep troubleshooting and work on these trucks. Anybody have any ideas? If you know somebody that might be able to help, tag them or PM me their phone number.

Thanks fellas! If you figure this out for me, drinks will be on me for the entire night!

 

Sorry to hear about the troubles Alex. Given that @papasmurf has pulled his rack like 3 times, I'm wondering if it's something else. I know, you change one thing and have a problem.....check the thing you changed. But it's sounding like you've checked pretty well. Anything else that it could be?

 

My only thought relative to the clock spring is if it was off one full rotation and then zero pointed in software, is it possible the spring tension is different and causing an inaccurate reading of steering angle? Like it’s tighter or softer maybe?

 

The only two possibilities I can come up with are:

Malfunctioning Clock Spring, although I don't know how to prove this. It's live streaming the proper steering angles.

the sensors do not like to actually be "level". This is why some people shim the sensor. Maybe I need to raise one end of the truck and then zero it so that when it is actually level, the sensors read something other than 0.0. This theory seems weak to me also. What would be the point of a zero calibration if you didn't want it to be 0.0 when its level?

I don't think so. The senor should read accurately throughout its range. Its either operational or its not. I'm not showing any codes or trouble lights. But this it the only piece of electronics that was affected by the steering rack swap so it is possible that its bad. The problem is, I have to prove it somehow before I spend time and money to swap it.

 

Check this out. The steering angle sensor can read several thousand degrees. So multiple rotations of the steering wheel. So it's basically a hall effect sensor (uses magnets)

 

LOL decided to double tap this argument i see LOL

 

UPDATE:

So I've never been able to get this fixed.Recently I broke some teeth on my steering rack and I had to install a new one. Well, because I was doing this I decided that would be a good time to replace the clock spring so I bought one. But it turns out that the CLOCK SPRING is a separate part from the STEERING ANGLE sensor haha Well I decided not to bother with the clock spring since it doesn't seem like that would have any thing to do with my problem. I replaced the rack and got an alignment.

Then I went to Baja. Well, on day 2 I started The Truck and my dash lit up. I connected techstream and found a bunch of codes; wheel speed sensor, engine bank 1 and 2 rich, etc. Long story short, during troubleshooting, we decided to do another Zero Point (on perfectly level ground) to try and reset a wheel speed sensor. After that I had no more codes everything was good. The VSC sensitivity was gone! I thought I fixed the problem, but it only lasted for a few miles then it came back. So now I am truly stumped. Here are the known factors and some questions:

• My clock spring is definitely bad because my horn does not work. However, the Steering Angle Sensor is a different part. When I view the Steering Angle with Techstream, I can see it reading the steering angle properly.
• Why does the VSC sensitivity go away after a Zero Point, but then come back? Is there a period of time after a zero point that the truck is learning or something? Do I have to drive the truck in a particular fashion after a Zero Point? Like maybe drive it straight or flat level surface or something?
• The Service Manual contradicts itself. To reset the Steering Angle Sensor, you have to disconnect the battery. However, in one section it says to disconnect the battery LAST, in another section it says to disconnect it FIRST. @n2deep has the same problem as I do and he's done it both ways and neither has fixed it for him.

Anybody have any ideas??? This problem is driving me crazy. The Truck is basically in limp mode unless I disable VSC because it brakes on every turn. so I have to remember to disable it all the time, but thats a pain in my ass plus I really want my VSC back.

 

I also found out the angle sensor was an integrated, but separate (and expensive) part while changing my clock spring cable.

I suspect your problems started when the alignment shop reclocked your steering wheel. Does a Zero Point calibration reset the steering angle stored in the ECU to zero when you do the calibration? When you say you measured, I'm guessing that was at the tie-rod ends?

There is a method in the service manual for adjusting the steering wheel position (follows rack replacement procedure): A line is drawn on masking tape across top of steering wheel, drive straight 100m (358') at 35 mph, measure the steering wheel offset distance, convert that distance to steering wheel degrees, then make changes at the tie-rod ends. I doubt the alignment shop followed that procedure; I bet they simply rotated a splined joint somewhere along the steering shaft. I would follow up with exactly what the alignment shop did. By doing a zero point calibration after their "reclock", you may have inadvertantly "shot yourself in the foot".

What I would do (bwdik): If the steering shafts are marked with center (match) marks, I would reset the shaft marks after positioning the rack in the center position, center the wheel using the service manual procedure, reset the steering angle with the wheels straight ahead (can't find SM procedure for this, but it has to be there), clear all the codes, do a new Zero Point calibration, and pray.

Edit: @osidepunker Once you done everything above to reverse the changes made previously, it's possible you may also have to remove the angle sensor from the back of the spiral cable assembly (while replacing that), and adjust the ring back to the arrows (zero position) to match all the other changes you've undone. The ring is indexed to the steering column once it has been zeroed.

If all this doesn't fix it, you'll probably have to send it back to the factory to have it "rebuilt". jk.

 

• Yes, the Zero Point procedure resets the steering angle stored in the ECU to zero. I have verified this using techstream
• I did the Zero point after the alignment and still had sensitive VSC. There is no reason why you can't clock the steering wheel at the shaft as long as you reset the steering angle sensor. This is the correct way to do it as per the Service Manual.

This might have something to do with my problem. I wonder of the steering angle sensor works together with the clock sensor somehow? I have been assuming that the steering angle sensor is not bad because I am able to read the steering angle in real time using techstream so its seems like it should be working

 

On my first new car, intelligence-challenged techs messed up the steering wheel position with an azz-pit alignment, and then deformed the steering wheel into a bow-tie trying to pull it to reclock the wheel to fit their alignment. The entire story is too long to tell.

Logically, it seems like that should be true unless there is something we don't understand the entirety of the Zero Point calibration. The procedure I'm referencing starts on page 9305 of the 2015 SM. Not sure why they would put it in if all the tech had to do was disconnect a shaft coupling and rotate the wheel.

The two parts are both providing unique functions. I can't see that there is any need for them to work together beyond being simply indexed together to rotate with the steering wheel shaft.

The spiral cable is not providing anything beyond electrical continuity as far as I can tell...you simply have to center it to keep it from breaking when you turn the steering wheel from lock to lock. The fact that yours seems to have been fine before, and is now broken, says that someone got it out of center position. I also doubt that the steering angle sensor is faulty because it appears to have been working fine before the rack replacement, and nothing changed (except the alignment and reclocking of the wheel by the shop). I don't know if a steering angle sensor has ever gone bad...it's a pretty simple, bullet-proof design.

When I first examined my angle sensor, I realized there was no physical limit to how much the rotor would move...it simply measures 0-360 degrees, then starts over again. I had no idea the ECU was counting rotations and keeping track up to 3200 degs. I rationalized that the ECU is not really interested in anything beyond a few degrees off zero. Imagine the front wheels suddenly being 90 degs from straight; I doubt there's any ABS or limited slip function that could help you with that.

Anyway, I'm way out of of my depth here. Just some thoughts. Good luck.

Edit: Actually, iirc there are like 3.5 turns from center to lock (or lock to lock?). Your front wheels being at 90 degs (not physically possible) would be more than 3.5 X 360 degs.

 

Any update on this? I've been having a similar issue for a month or so.

 

I still actively have this problem. I haven't had a chance to really dig into it. But in the next couple weeks I plan on attacking it

 

Bear with me guys. I still have this issue but I havent had a chance to get serious about it. I am going to dig into my OV Tune and then the VSC problem is next on my radar. I should be able to get serious about troubleshooting this in the next few weeks.

 

Tell me more about that wheel speed sensor code from when you were in Baja. (Post 7)

Was the sensor replaced, or pulled and inspected?

Have you monitored wheel speed sensor signals with techstream while driving at very low speeds? All wheel speed sensors should read down to 1 mph, if any drop to a zero speed signal when others are still reading 2+ mph you have an issue, and you won’t necessarily get a fault code for it. Make sure they are reading correctly for fwd /reverse rotation too.

If any don’t read right, it might not be a faulty sensor though. Iron filings (from a wheel bearing failure) stuck to a sensor can cause a poor signal, as well as damage to the magnetic reluctor ring in the wheel bearing.

 

I'm not sure why I got a speed sensor code in Baja. That was last March and I have not had another code since then.

I have monitored the wheel speed, put The Truck on blocks, and turned a wheel by hand. I didn't do all four wheels, I just wanted to see how sensitive the speed sensor is. Yes, it reads down to 1 mph

I chalked it up to an anomaly as it hasn't returned

 

wait, are you suggesting my VSC problems might be a faulty speed sensor? Maybe one that isn't necessarily throwing a code?

 

That’s exactly my idea. VSC activates based on steering angle, yaw rate, and wheel speed signals. You’ve been looking hard at the steering angle which makes sense with how your issue started, but I wouldn’t overlook a speed sensor issue as being a possibility.

 

gotcha. Thanks man. Ok, I'll put it on blocks and turn all the wheels by hand, forward and reverse, and look for any weird readings. Anything else I can do to verify all the sensors are legit?

 

You can have someone watch the readings in techstream while you drive at a snail’s pace, instead of jacking it up. You can check that all 4 signals are equal when you’re driving in a straight line that way. Either way should give you a good idea though.

Keep us updated.

 

Ever figure this out. Im having a similar issue after installing slightly bigger tires (275/70-18) and also finding out that the alignment shop didn't do the ZPC. But ended up having Toyota re do the alignment and the ZPC. But still on a turn, corner or when trying to accelerate hard I still get the VSC slip light and it kills the power.

 

Well, I'm not sure. A few weeks ago, I finally replaced the clock spring and centered the steering angle sensor. Then I did a zero point. When I drive and check the sensors on techstream, all the values appear normal. All the steering angle values are centered and agree with each other, the G force values are all normal, ie 0 when not moving and normal values when moving.

Off road, the skid control feels like it kicks in like it used to. Take a turn too fast and it will come on. So in that sense I have fixed my problem. I like having it on off road for when I take a turn too fast it will save me from running off the trail. It doesnt seem overly sensitive compared to what it was like before I broke the clock spring and caused all my problems.

However, its more sensitive than it used to be on twisty mountain roads and certain freeway off ramps. I dont understand. And to be honest, I am at a loss as to what to check next so I have kind of given up

 

I totally forgot to check this. I did replaced a speed sensor a few weeks ago because I broke the connector on a bush. But this thread reminded me to check them at low speed like you suggested.

 

I am having the same exact issue. I figured it was just due to the lift and or wheel size setup. I just turn off VSC when I hit the mountain roads now

 

Yeah its bothering me, but I cant pin down whats causing it. I refuse to believe it has something to do with a lift, because I have had many different suspension setups including the current setup and I did not have problems before

 

Yeah im almost thinking it has something to do with the Yaw/Pitch sensor then?

 

but those sensors are reading correctly. If Im driving flat and level and straight, they show zero. If I take a turn they increase. Hard turn where they kick in the yaw shows about 10, climbing a hill the pitch shows about a 1, steep is 2 or 3. Stopping hard around 5 maybe

seems to me like they are reading correctly but idk

 

Good point, I need to figure out how to get this software so I can check mine.

 

Bringing this back from the dead. Did you ever get it resolved or did you just get a new truck? Haha my issue happened after I went to 35s and level kit. Been driving with the issue for many years. I've done the reset multiple times and even tried the shimming and resetting...