VSC (or ABS?) spontaniously engaging and loss of acceleration...
 

Hello all,

My car is doing something very odd, and very frightening... It started with a lack of acceleration. The car would not rev past 2500 RPM, no matter how far I pushed the accelerator. Also, the transmission would not "kick down", again, regardless of throttle position.

This happened a few times, but the one that REALLY scared me was when the ABS spontaneously engaged and a loud buzzer came on in the dash. The car immediately pulled HARD to the left, almost running me into another lane...

To give you all some background, I had just finished a complete front and rear suspension/bushing/tie rod/etc replacement and had just had the car aligned (It was WAAAAY out of alignment, like 45 degree steering wheel). It was working fine for about 10 miles. I filled up, drove about a mile, and then the lack of acceleration issue happened. It seemed to resolve itself when I came to a stop so I could make it home. The next day I took it out and got a few miles before it happened again.

Then, out of the blue, and driving at about 30-40 MPH the ABS spontaneously engaged, making the car pull hard to the left. When this was happening (for about 2 seconds), the traction control light was on and a warning buzzer was going off in the dash...

I'm not sure how the suspension/alignment/fueling would play into this, but I don't think this this was a coincidence... The car had exhibited NO issues like this before, and other than the "slick road icon" flashing when the ABS module cycles, there are NO warning lights on the dash.

ANY help would be GREATLY appreciated as I'm scared to drive this thing right now...

A zero point calibration should help reset the steering angel sensor. You can do this yourself, big thread on here about it. After ZPC procedure is complete drive straight at 40mph for 10 seconds or more to complete the reset.

For the acceleration problem , check for blown ETCS fuse, loose battery cables, or similar.

Thanks, was planning to do the ZPC after work this evening. Is the thought that these two items are not related to one another through a common system? Does VSC have access to both ABS and throttle?

Did you do all that maintenance yourself? Or did you pay a guy? I'm going to assume that in the process of ripping all the front-end stuff apart he snapped one of the ABS sensors off or broke it or didn't plug it back in or something but I'm willing to bet that there's a sensor somewhere thats whacked out should try and get it up in the air and take a good look at everything under there make sure everything is plugged in and nothing is snapped or broken.

not exactly related in my third gen my four-wheel drive stopped working I even posted a forum of here A bunch of years ago about it it ended up being unplugged from something I was doing and forgot to plug it back in.

It's a little different but I just did all of that same maintenance on my car Lexus ES granted that's a car the chances of breaking one of those sensors during that maintenance was very high considering their location.

Did the work myself, except for the Alignment which my local Firestone did (and the steering wheel is still off by 1 or 2 degrees).

I never disconnected the wheel sensors, but I also don't explicitly recall verifying their connections either.

That being said, could wheel speed sensors throw off the acceleration as well, or is that something that's unrelated?

I wouldnt think so but maybe i would assume that a speed sensor would just throw speedo off but ive only had my 4th gen for a few days i know in the older ones it wouldnt make a difference...

Something similer happened to my buddies mustang it ended up being a plugged catalytic converter.... I never trust a tire shop there is one here in wisconsin that i had proof on would break your vehicle so you would have to go back especially if the customer was a woman.... Plus they also hire young very stupid kids to do the work.... If it where me i would be blaming the tire shop....

You probably said it already but do you have any dash lights on? Maybe get it plugged in and see if something comes up.

I'm going to also step in and suggest a Zero Point Calibration. I've talked with others in similar situations and that resolved the issue.

In short, your vehicle thinks that it's in a more dramatic angle/position than it really is, and kicking in safety features to compensate for a problem that isn't there.

Well, after a LOT of digging around it does looks ZPC is the route to go. I'm have been traveling so I haven't done it yet, but based on this TSB:

http://4runnerclub.com/i/4r_files/fs...SB-0020-08.pdf

it's required anytime you do an alignment or chassis components have been replaced...

I replaced EVERYTHING front and rear and did an alignment, so I'm certain this is the issue now.

I just need to find a level spot to do the actual calibration. My driveway is level left/right, but I need to jack the front of the car up about 4 inches to make the running boards level.

In addition, this thread on the 5th Gen forum should prove useful as I need to do ZPC on the DAC as well:

Yaw Rate and Acceleration Sensor Zero Point Calibration

Wait, hang on.

You want to do the test on level ground -- you are correct. (I usually use a parking lot.) However the truck should be sitting on that ground "as it drives." If you jack up the truck when you do this procedure, you'll get an incorrect calibration.

What you're teaching the truck by doing a ZPC is "This is what the truck looks like when sitting on flat and level ground." To make an exaggerated point -- if you performed the ZPC when the truck had a flat tire in the rear left, the truck would then think that the front right end is dipping forward several degrees in that corner once the tire was repaired.

Understood, what I was trying to say is that my driveway is sloped downward about 3-4 degrees. To compensate I could jack up the front until the car is level and then do the ZPC.

Other option would be to just drive to a nice level parking lot and do it there.

Jacking up the front and then using wood blocks under the tires to get it level and then remove the jack/s could possibly work but the tires need to be supporting the weight of the truck, even then it could still be off and would be best to drive to a level spot so the front tires are settled to their rolling configuration and not just let down off a jack onto a level spot because the alignment will be slightly off until the vehicle moves/roll in a straight line a bit.

Update
 

Hello all,

Sorry for the delay, I thought I replied to this a LONG time ago...

I thought I should close this out by stating that I got the car to a level area and did the reset, and all has been well ever since. That was 5+ months ago now and I haven't seen the issue since. Thanks for everyone's assistance!