BrianB

So I have an '02 5VZFE 4Runner SR5 and had a problem that was pretty similar to the one that TJM described in another thread. Basically I would be driving along and the VSC light would come on and the deet-deet-deet-deet VSC alarm would start screaming. Sometimes it would also kill the throttle, sometimes it would stutter the brakes if I happened to apply them, and sometimes it would just scream its fool head off until I slowed to less than around 27 miles per hour and then it would shut up.

Sometimes it would come back once I sped back up. Sometimes I had to pull over and get to 0 miles per hour in order to keep it from coming back once I sped up. Sometimes it seemed like having a passenger made it worse. It was kind of all over the place and VERY annoying.

Wifey (who is a good diagnostician and mechanic) started doing research - a lot of it here on yotatech - and had all sorts of ideas. Steering wheel position sensor, reset VSC zero point (the suspension is a little worn but not that worn), bad pitch/yaw sensor - all sorts of ideas.

Time drug on and the problem got worse - and by worse I mean it happened more often. At some point I did notice (like TJM did in his thread) that it seemed more common upon returning to normal speed after making a low-speed turn, and/or during a turn if it was one that happens "at speed" (such as a highway on ramp).

With the benefit of some of Wifey's research (specifically the part about the steering wheel position sensor) I had an idea. To test the idea I had Wifey lay on the ground and observe the steering rack while the vehicle was stationary and I turned the steering wheel.

My theory was right. The rack bushings were VERY shot, and when I turned the wheel the rack could move left to right quite a bit.

The reason this causes an issue after a low speed turn or during a high speed turn is that when the rack slips you have to turn the wheel further, which the steering wheel position sensor knows about, but the trajectory of the vehicle doesn't change and the pitch/yaw/accelerometer knows that. The computer then determines that you must be in a skid.

What's really funny is that sometimes I'd just be driving along and it would start screaming and it would keep screaming for like 5 minutes as I went miles down the road. I had to chuckle and ask the computer aloud (it did not answer) "do you really think it is possible for me to skid for 2 miles at this speed?"

Anyway, the long and short of it is we had the rack bushings replaced with 3rd party urethane rack bushings (the dealer said the OEM bushings can't be had except with a new rack) and now in addition to the steering being very responsive and wonderful again, the VSC problems are all gone.

As a side note, eventually the problem got so bad that when in a turn at speed I could feel the rack slip and notice having to crank the wheel a little more to hold the turn. But this was after I had already figured out the rack bushings were the problem. In the early stages of the failure the rack didn't move quite so easy and it took something like a u-turn to move it and induce the issue.

Anyway, I hope that helps save someone a ton of troubleshooting and frustration. If you're having insane VSC issues on your 4Runner have a helper observe the rack while you try to turn the steering wheel both direction. If the rack moves in its mounts, that's probably your issue.

habanero

Nice job for you and the wifey, thanks for posting this up for others.

aowRS