Wondering who might have experienced Check engine light & VSC light on, car drives fine, no drop in fuel economy, my mechanic said it is associated with some engine design problem, should take it to dealer, engine need to come off, Lexus should cover it? But my car is already out of warranty, I am not sure if dealer will cover it?

 

Have you done ANY research at all? Judging by your post count I'm gonna say no and the answer to your question is to RESEARCH.

 

Sounds like a carbon buildup problem

 

I have came across posts on carbon build up issues with the IS250, have you encounted the same issues?

 

The carbon issue is very common, tons of information on it.

 

If it is the "carbon issue" it is covered for 9 years, unlimited miles.

 

Did you just change your Valve Cover gaskets seals? If so, have your computer reset or removedyour negative battery for 60 seconds. This may turn your VSC light off.

I did a valve cover gasket seal repair and my vsc light came on. I turned the light off with my OBD II tool and it did not come back on.

 

There is a lot of problem relate to CEL and VSC. We need more info to able to help you out. By the way, did your "traction light" come on as well? Best way is stop by at your local auto store and ask them to scan for error code.

 

^^ scanning is your best bet. I had the same problem, the vsc and the check engine light came on at the same time. Got it scanned at autozone and it turned out to be bank 1 sensor 1 was out. Changed that bad boy out and all codes went away.

 

I am having the same issue after changing plugs and valve cover gaskets. The code is P0154 which indicates the Bank 2 Sensor 1 is unhappy. But, I replaced the sensor and erased the code and the code comes back. Sometimes it also shows P0153 which is 'receiving slow switching' from the sensor. I watched the switching on my scanner and it is in tolerance and seems to happen every few seconds which is what it is supposed to do. It's frustrating to do a simple repair job and have it create more problems....when I know I put it back together right. I've done a lot of research and a lot of people have had similar problems...but no one ever posts what they did to fix it.