I also had the same problem today. My
car is Highlander '02 64K miles V6 Limited.... Both the engine light and VSC light went on. I had the oil/filter changed a few days ago at the dealer. I'm so glad I found this forum! After reading about the vacuum hose I went out to my car and found it the problem. But, knowing what I knew I decided to take it back to the dealer to see how honest my trusty dealership really was. Turns out they admitted it was thier fault and that they overlooked checking the hose that caused my lights to go on. There are honest dealers out around for the most part. For anyone reading this in the Chicago area the dealership I'm talking about is Elmhurst Toyota.
Thanks!