Diagnosing Violent-Jerking Steering Issue (VGRS) (1 Viewer)

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Dec 10, 2018
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Location
Denver
I will preface this by stating that this is not an issue of loose wheel bearings trigging ABS system to grab a tire. This one has @2001LC and I somewhat stumped. I've also gone through most of the VGRS related threads and found good info to inform investigation but no conclusion yet. Paul has had the truck for the day and we'd like pick the forum's brain to see if we're on the right track.

2003 LX - pretty heavy with lots of bits and bobs.

IMG_6001.jpeg


Symptom: While driving at almost any speed over 20mph, the steering wheel will start to shake, then "violently" jerk the vehicle to the passenger side. It will then settle a little, shake more, then repeat. If you stop the truck and let it settle down, it will take a brief hiatus before starting again. It also seems to get worse the longer you drive at speed. It is unsafe to drive in this state and I had it towed back from Glenwood Springs.

What We Know:
  1. Wheels bearings/knuckles were rebuilt by @2001LC about 2000 miles ago and were checked again today at his shop. Still tight.
  2. SPC Upper ball joints were replaced in May.
  3. 1 new 555 lower ball joint replaced during last knuckle rebuild and the other tested to be ok.
  4. LAND CRUISER steering rack put in by Slee in 2020. Steering always felt heavier after rack was replaced, but seemed to function ok. No leaks currently and ATF flushed once per year. Tie rods seem fine. VGRS light has always turned on at start and turns off as expected.
  5. Fresh Wheels and tires put on last week. Alignment also performed. I drove it to Grand Junction and issue presented on the drive back. Thought it could have been an unbalanced wheel but that doesn't seem to be the case. Control Arms bolts are tight.
  6. VGRS Light remains OFF. Paul plugged into tech stream today and it showed no major errors. He also unplugged the VGRS ECU, took for a test drive, but problem remains.

So with all that said, the front end suspension components seem to be in good shape, leaving only the PS system/VGRS to be the culprit. As there are no VGRS codes and light is OFF, we are guessing malfunction of the VGRS actuator on the intermediate shaft, but don't have a way of verifying. Does is seem like this guess is on the right track? Anyone with a similar experience?

And further - this part is EXPENSIVE. It looks like some folks have replaced the intermediate shaft with the LC parts and they fit, but VGRS light remains on dash and inconclusive if this affects ABS, TRAC, etc.

Looking for any advice here before forking out 3-4k on a guess.

Thanks!
 
Do you have after market control arms? Possibly the castor angle is not adjusted correctly. This could lead to "death wobble" which sometimes behaves like you note. It happens only at some speed b/c it is a dynamically constructive interference (basically builds with speed). Sometimes inputs can momentarily stabilize or destabilize it.

 
I do have SPC uppers and I suppose a cam could have slipped, but I thought death wobble wasn’t really a thing on IFS. Caster was set to about 3.1 on each side.
 
You give a fair bit of history, but when did the vibration/wobble/veering start?
 
Sorry! About 350 miles and the day after alignment/new wheels tires. Tires went on Friday, issue appeared Sat.
 
Before I’d start pointing the finger at VGRS, I’d be thinking VSC (any alarms when it veers?), and/or wheel/tire/mount issue (still have the old wheels/tires? If not can you beg/borrow/steal a set for troubleshooting?).
 
I’m no tech, but alignment/wheels tire seems like the obvious problem.
I’d lean towards alignment.
 
Before I’d start pointing the finger at VGRS, I’d be thinking VSC (any alarms when it veers?), and/or wheel/tire/mount issue (still have the old wheels/tires? If not can you beg/borrow/steal a set for troubleshooting?).

Thanks guys. I do have the old set of wheels and tires to try and will do that. I think it's also reasonable to check the alignment (and I'm planning on it), but what's so odd is that it gets progressively worse as you drive the truck longer. First ~5min it drives straight as an arrow then the jerking starts to ramp up. Also no alarm chime or VSC flashing when this happens. I've been in a different 100 series with that issue and this is not the same.
 
I feel like a lot of these threads wind up with front steering rack and diff bushings being the culprit. The steering sensors get confused when there isn't a firm anchor for them to detect steering angle, and the system thinks it's at a different steering angle than it actually is.

I trust Slee to do something as simple as a steering rack, but did they replace all the associated rubber bits?

If that all looks good, then the next question - does it "feel" like more of a mechanical pull (like death wobble or bushing stuff)? Or does it feel more like the computer is sensing something and locking up a wheel etc. which is causing the violent pull?
 
I know this may be a long shot, but have you checked to make sure that your wheel speed sensors are installed flush into the knuckles? A cocked wheel speed sensor can cause all sorts of havoc. A quick check and it's free!
 
Post your alignment sheet-
What brand wheels what model and part number?

Are they fully clearing the front flange and seated on the hub( I test mounted some 5x150 110 bore fuel wheels for a tundra that wouldn’t clear the LC front hub)

Since everything was fine before new wheels and tires-(and alignment)- this is your target range of diagnosis.
 
When I purchased heritage wheels that had some ridge grapplers on them, it did this. My plan of attack was to make sure all ahc levels were correct, alignment was correct, and pressures were correct. I had a little play in a wheel bearing, and my front diff bushing needed to be replaced. Nothing helped more than replacing those tires with a non e rated tire and making sure ahc fender heights were correct. The rear sensor nut had come loose so the angles were wrong, too high in the back. Imo, the tires made the biggest difference. Alignment and balance all was good, new tires, wobble gone. My tire shop that I’ve used for decades reiterated e tires shake the steering wheels many times. That this happened after your new wheels and tires, I would say this is 100% the causation in my personal opinion. Good luck. These trucks are smooth when they have the right gear and setup.
 
To be clear @pili in your OP remark: "This one has @2001LC and I somewhat stumped." It does not have me stumped. It is clearly a VGRS issue, that I've no doubt of. But, I've yet to put the time into determining the "what" & "why it happened". Which we need to know before, before any repairs begin.

We're 98 percent sure VGRS is causing steering issue. We're 80% sure it's the VGRS actuator, that is malfunction. We need further testing to get to 98% sure, on both counts. But before replacing any parts, which is the acid test. Whichwe've assume is the actuator, that failed. We need the why. Because "If" (a big if) the why, due to excessive pressure on actuator, due to use of the non VGRS rack & pinion. We must address that rack also.

Time line:

Last August, Alex reported, to me. Steering hard at low speeds. I said I couldn't comment on that, as he's built heavy with over-sized tires. He said his buddies LX similar yr (VGRS) & build was easier to steer at low speed. I did however point out, he has the wrong rack & pinion. That his is an LC non VGRS not the LX VGRS R&P. He said hard steering began with the LC rack install, which until then though was a VGRS R&P. HUMMMM! I have now driven LX VGRS steering equiped, both with LZ non VGRS rack & pinion & LX VGRS R&P, stock (tires and weight) configuration. I did notice in the one other stock LX I drove with LC rack, it did steering harder at low speed, than those with LX VGRS rack.

@pili (alex) called me while on the road Friday, on steering issue between 35 and 70MPH. The way he describe handle (what he felt), along with new tires/wheels/and fresh alignment. Along with perfect handle drive out of town and off road. For ~350 miles from Den, West on I-70 over the mountains, than off road (dirt service roads mostly). That condition only began on drive back to Denver.

First thoughts were tire balance, loose lugs, alignment. I had him look at wheel balance weights. He found one (LF) out of the five wheels/tires, without any balancing weights. I suggest he check lugs torque, and swap spare to LF. He did. No help!
Note: I looked at wheel (new) without weights. No sign it ever had any.

I also suggested he check wheels bearings. He did and reported them loose. Said he could even hear a sound as rocking at 12 & 6 o'clock.
Note: Subsequently I found wheel bearings, were/are not loose.

He had towed to me.

I found wheel bearings were/are not loose. Checked wheel hub with dial gauge, zero movement on dial and 10lb BPL. What he and heard during standard wheel bearing check. Was, SPC upper ball joints movement. Which may be normal movement IDK, but suspect is normal movement. Which does feel much like loose wheel bearings and "sound" like supper loose wheel bearing, when testing with jack under LCA.

Lugs torque on both FR & FL,okay.

I looked over the front end and it seems in very good shape. Just as it did after I worked on front end & timing belt, etc. last summer. Nothing remarkable, except a non VGRS rack was noted back then or now.

Test drive OH SH*T:

On test drive, it was handle very well no issues, AT FIRST! But after driving on city streets, for about 4 miles, at speed for 20-35 average up to 70 MPH, all good. I then took on the HWY, OH SH*T! Less than a 1/4 mile on HWY, and vehicle suddenly turned to the right about 20 - 30 degree, then steering relax to straight. It repeated this with greater frequency an intensity. I could feel in my hands, gearing hit clucking and back off repeatedly. I instantly knew VGRS manufacture. It was unmistakable, even though, the first I'd ever seen/felt.

I unplugged the VRGS actuator, took another test drive. Same results. I found in takes some driving (warm up) time, before steering gets going wacky. Speed wasn't the factor, as I kept under 35MPH. Turns, did seems to make it malfunction sooner. With VGRS unplugged, it would "seem" it's mechanical in the gears of actuator. But this is something I'm speculating on. I need to study more on the subject. In that, could lack of power/signal to actuator cause these type of reaction. I'll try unplugging my 3 LX's with VGRS, see how they react.

Current thinking is VGRS Actuator will need replacing. But before we order the part. We'll be going through FSM diagnostic tree, see where it points. We'll also re-calibrate all systems. I've ask Alex to have realignment done. As toe is now out. I do think toe out was caused by, action of steering jerking to the right and back (very unsettling to drive). That be best to recenter rack, before alignment. As numbers of teo, indicate rack mounts move to one side. We'll just loosen mount bolts, find relax point and re-torque.

He just had alignment done last week, and had re-checked today by shop other than set last week. Toe is evenly out of spec to one side. Good caster for the SPC UBJ & UCA, and has about 1" rake, good rack bushing and gears seem fine (2 yr old R&P). (no wondering issue on HWY.)

22-12-14 after steering issue.jpeg
 
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Makes more sense with the rack description, if it’s not correct. Hopefully he gets his other wheels on the eliminate that.
 
We may find re calibration is all that needs, we hope!

Once we know what's wrong, if not just calibration. If it is a part failure. We also need to determine why.

"If" failed actuator. Was any outside force causing malfunction or resulting in shortening its usable life.

It's the non stock parts we'll be looking at first, as top consideration.

1st being the non VGRS rack. That fact it seems steering becomes harder at slow speed with non VGRS rack. One possible conclusion, would be excessive force on VGRS actuator. Add larger tires and heavy weights, to the mix. Hummm, new tire push it over the edge! HUMMMMMM
 
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I found this reference in FSM to heat. Worth noting since we're seeing issues after steering use, for some time. It has not happen, from a cold start up.
"When protecting the VGRS system from heat. (The system is suspended to prevent the VGRS
actuator motor or ECU from heating up. The system returns to a normal condition when the temperature
of the VGRS actuator motor returns to the operating range.)"

Also worth a note: The Actuator, needs power to activate a solenoid which unlock actual from fail safe. Loss of power and it is locked in Fail safe for safe and noraml feel driving mode. We had no change in malfunction steering, when actuator unplugged.

I did hook-up tech stream and check for any DTC, NO VGRS DTC, NO CEL or NO VGRS light (VGRS light does work, during key on self check).

The DTC you see below, have been active since AHC delete, is my understanding.

I've not done a comprehensive system diagnostic. This is just some pictures I snapped while in tech stream. Wherein I did turn steering wheel lock to lock and hold near each lock (lock than relax off lock 1 deg and hold 3 seconds or more). But I did not follow any procedure. So numbers out of spec, may be meaningless.

IMG_2134.JPEG

RH turn (- deg)
IMG_2135.JPEG

LH turn (+ deg)

IMG_2136.JPEG
 
The DTC you see below, have been active since AHC delete, is my understanding.
Probably not really relevant to the issue that you’re chasing, but I believe the 3 AHC DTC can be made to go away, by unplugging the bottom two connectors on the AHC ECU. The 4th body DTC appears to be a “rain sensor” (even less relevant to your issue).
 
By reading through the symptom, I would prioritize check and do a process of elimination on the following (in no particular order):
• if castle nut for both upper and lower ball joints are tight
• if inner and outer tie rods are tight
• if rack end pinion bushings have no play
• if steering shaft u-joint is tight
• if upper and lower control arm are tight
• basically rule out the mechanical hardware aspect related to the steering system

• if possible, lift/jack the vehicle four wheels and run it see if you can replicate the symptom w/o load on the wheels

Once I rule all these out, I’ll move on to the software/component part of the VGRS.
 
By reading through the symptom, I would prioritize check and do a process of elimination on the following (in no particular order):
• if castle nut for both upper and lower ball joints are tight
• if inner and outer tie rods are tight
• if rack end pinion bushings have no play
• if steering shaft u-joint is tight
• if upper and lower control arm are tight
• basically rule out the mechanical hardware aspect related to the steering system

• if possible, lift/jack the vehicle four wheels and run it see if you can replicate the symptom w/o load on the wheels

Once I rule all these out, I’ll move on to the software/component part of the VGRS.
Thanks! All has been checked: by Alex while on the road after, 2 alignment shop one before and now another after, by me last summer and after event.
Except: "if possible, lift/jack the vehicle four wheels and run it see if you can replicate the symptom w/o load on the wheels" Funny, I just did this for one of my 07LXs, with rotation very mild scraping sound. Darn if it would yield a sound, on stand running wheel spinning.

All tight and in excellent working order. In fact, I ride a ride along on my test drive. He commented; He wish his felt and handled as well". Until we jump on HWY, and steering went wild. Then is was white knuckles for us both. Got off HWY ASAP.

No work preformed in in last few thousands mile or months. Except: wheels/tires and alignment. Done 350 miles trip out which no issues what so every, until on way back from some mild off-road time (service road).

Again, are hopes are calibration issue. But are hopes were a bit weakened. When condition repeated, when actuator unplugged.
 
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I suggested the thread be posted. To fish not only for solution, but more so for others with same issue. In particular, those with a LC Rack & Pinion (non VGRS R&P) in a VGRS system (LX 03-07). Maybe we need a title change or new thread.

Alex & I are both very interested in any difference, changes or issue with steering. When LC R&P used in a VGRS system (LX 03-07). As anyone with an LC R&P in a VGRS system should be.

This includes:
Hard steering at low or stopped speed.
Over or under steering at any speed. But mostly high speed over-steering.
Similar steering malfunction, in any VGRS system.

I found that the VGRS Actuator P/N changed in mid 04 model, then again two more times (total 4 P/N's). Was this to correct defect? if so what was issue?.
 

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