Originally Posted By: wolfehunter
quint, funny you mention a bad O2 sensor because the check engine light came on a while back so I had the code checked and I have to replace an O2 sensor as well!! Sounds like I need to get busy and change the bad sensor as well as get myself another tire. Thanks again!
Yes the first time I had problems with the system it was an O2 sensor (check engine light and both VSC lights were on). It worked fine for about a month or so after I fixed that, then the VSC lights came back on (no check engine light this time). Unfortunately a regular OBDII scanner cant read the codes the VSC system throws, so I had no way to see what was causing the failure. I then went to the tundrasolutions forum and did some searching and found a way to read the VSC computer codes by jumping a couple of connections on the OBD connector plug. I was getting a brake system pressure imbalance code. This made sense, as the brake pedal had recently started sinking down low while my foot was on the pedal at stoplights. I replaced the master cylinder and bled the brakes, and now the pedal is firm again and the brakes work fine, but the VSC lights are still shining and the code is still there. The at-home procedure for clearing the VSC computer codes doesnt seem to work on my Sequoia, or the sensors are bad giving bad readings. The sensors for this code are thrown by one or both the two sensors on the bottom of the master cylinder. One Toyota mechanic said they had a lot of issues with a few batches of those sensors going bad and detecting a pressure imbalance that wasnt really there, the only solution being to replace them both. Unfortunately there is no easy way to check them myself (that I have found, at least) so I aimed to replace them, until I researched the cost. Now I'm waiting for another Sequoia or Tundra to show up in one of my local junkyards and I'll shotgun it with used sensors until I fix it and figure out how to clear that code (disconnecting the battery doesnt do it either).
I had no check engine light in this truck at all, ever, in 10+ years of ownership until they replaced my frame under the recall, last summer. The check engine light has been on four times since then. Everyone said this would happen.....
I contemplated just removing the VSC warning lights and letting the system remain disabled, until I drove it a few times in some of the snowstorms we had recently. WHOA she became a whole different vehicle with the nanny system off. Almost put it in a ditch more than once. I didnt realize how much the dynamic of the truck was being controlled by that system until it wasnt there. Not a problem, as none of the other vehicles I drive on a regular basis have it and I get around in them just fine, but I do have to drive them very differently in snow than I have ever driven the Sequoia, I just need to get accustomed to driving it without the system there.
I did have the VSC lights go on for one tire that was very low on air, so its very possible your one mismatched tire is causing an issue. But if one of your O2 sensors is bad, that will also keep the lights on.
If you want to do some research on this very trouble-prone system, I would recommend the Sequoia section of the Tunrdrasolutions forum, there are many, MANY threads on VSC problems. Many, many, MANY threads......