Trac off and VSC off lights illuminated. Truck took over and almost made us wreck!!!

[bliggity]

So I’m driving with my wife this weekend and the trac and vsc light came on over a speed bump. I shut the truck off then restarted, vsc and trac lights were off, started rolling and immediately they came back on. Roughly 20 miles later we were driving on a flat road cruising at 50mph and the truck took over! I heard a beep and all of a sudden I was out of control. It was like an abs wheel speed sensor told one of the wheels to lock up. I turned the wheel to the right to compensate and it would then pull right then I would go left and it did this for 5 or so seconds. If you would have been behind me you would have thought I was trying to purposely flip the truck. Needless to say my wife and I were very shaken up.

I took the truck to a friend that has a repair shop and we scanned all modules and nothing pulled up. Not even in the abs module. I racked the truck and inspected and pulled all the abs wheel speed sensors but nothing seemed wrong with them. The vsc and trac lights will be off when I start the truck, I can push the "trac off" button and it illuminates trac off on the dash and I can turn it back off. When I pull the truck forward the trac off and vsc off lights come on within an inch of moving and I am then locked out from using the "trac off" button and the lights will stay on until I shut the car down. I also tried to recalibrate the yaw sensor but no luck either. No check engine light.

Any insight would be great. I'm pretty upset that my 4runner could do something like this, I couldn’t imagine if I’d been on the interstate I may not be typing this message.

 

[DC runner]

Have you checked the actual ABS cables to each tire? Kinda sounds like a loose wire.

 

[bliggity]

I checked the plug to the abs sensor but didn't think about following it back. I'll throw it on a lift and see. Thanks

 

[xxaarraa]

Oh man, sounds scary. Glad you and family are OK.

 

[TRDCal]

If vsc is triggering on speed bumps then it sounds like you might need "zero point calibration"

 

[aha2988]

x2 on the "zero point calibration"

 

[bliggity]

I tried the zero point calibration twice and the lights come back on after 1/4 mile or so.

 

[MarkieG]

Similar thing happened to me just this morning while driving to work - not as severe as your situation though. Glad you are okay.

I was cursing about 40mph approaching a red light. The intersection is concrete and extends 100 yards past all the crosswalks down the intersecting roads at which point the road surface turns into asphalt. When I drove over the surface change from asphalt to concrete there is a slight bump down and the Runner automatically applied the abs, but no lights or warning beeps came on. I had to stop applying pressure to the brakes then reapply, but it felt like cruise control was on and taking over the car! I drive over speed bumps in me neighborhood all the time (not at this speed) and have never had issues.

Needless to say, when I didn’t expect this to happen it gave me a brief rush of panic. I’ve got to get this checked out- let you know if I find anything.

 

[zonianbrat]

As much as I dislike "most" dealerships. If something like that happened to me I'd be raising hell at the dealer and making them figure it out since it is clearly a safety issue. Please do not think I doubt your own abilities to figure it out and fix the problem. But that is scary crap when your truck takes control and almost makes you roll.

 

[KidVermicious]

Glad you guys are ok. No offense, but every time I see a thing like this I'm glad I own a truck that doesn't try to do my driving for me.

 

[Cyrcle]

Glad you guys are ok. No offense, but every time I see a thing like this I'm glad I own a truck that doesn't try to do my driving for me.

I hear that! Makes me nervous to be in the market for a new truck. Wish I could get something with good ABS, good all-around air bags, proper crumple zones, AND NOTHING ELSE.

 

[Krazynative]

Similar thing happened to me just this morning while driving to work - not as severe as your situation though. Glad you are okay.

I was cursing about 40mph approaching a red light. The intersection is concrete and extends 100 yards past all the crosswalks down the intersecting roads at which point the road surface turns into asphalt. When I drove over the surface change from asphalt to concrete there is a slight bump down and the Runner automatically applied the abs, but no lights or warning beeps came on. I had to stop applying pressure to the brakes then reapply, but it felt like cruise control was on and taking over the car! I drive over speed bumps in me neighborhood all the time (not at this speed) and have never had issues.

Needless to say, when I didn’t expect this to happen it gave me a brief rush of panic. I’ve got to get this checked out- let you know if I find anything.

@MarkieG... What you experienced was normal ABS kicking in. When you hit the bump with the brakes applied, your wheels stopped rotating quicker than the system likes and thought they were locking up. If you kept the brakes applied you would have noticed normal braking coming back.

There are a few areas that I drive with the same transition at lights. I just release the brakes for that transition and I don't get the ABS thing.

As for the OP's issue, I would take it to a reputable dealer to check out. (Please don't flame me for this recommendation, as this seems to be life threatening)

One question to the OP. When doing the Yaw cal, did you clear the previous cal first? I noticed this step in the original TSB and it is not mentioned in some of the T4R members cliff notes. I have attached teh TSB that I have.

 

[BlackWorksInc]

I would take the vehicle to either a reputable dealership or shop that has the tools to properly work on a Toyota ABS/Traction Control System.

I would guess from what you described so far, there is an issue with the computer/electrical portion of the system and I doubt you will be able to find that on your own without a TechStream and some factory service information. Hell, I wouldn't be able to tell you more than I think its electrical/computer related without having the car here and tools on hand.

I do hope you get it taken care of, that is a serious issue.