the maintenance manual only says they have to inspect transmission for leakage.

it never says transmission fluid needs to be changed.

Lexus Canada says to drain and fill it every 96,000 km (60K mi). Just saying.

no it didn't just took a lot of gas and lack of power a little.
this seem like a tranny problem..but i dont know I had this problem with my old car if it lack of power and struggling on shifting it was due to coil pack I had to replace 2 of
them out of 6 it was the maxima v6

It appears you have 3 issues here........... If I am reading this correct.... your car is an '06 and you have 166,000 miles?? That's alot of miles for an 06, so maybe you need to have it serviced. Fluid issues are a typical cause for the check engine light to come on. Another cause of this, would be your O2 sensors. I have a 98 with 125k miles and O2 sensors is the reason my check engine light is on at the moment. I plan to get this done. As far as the vsc issue, this should be something to do with the speed sensors. That's how I solved my VSC issue. I hope this helps....

Rock

Go to a local auto store, let them plug in the OBDII machine for free and read the codes.

I had this issue and I had to spend close to 800 getting diagnosis and solenoid replaced.

It says VSC no matter what is going on, it's the dumbest error readout ever.

Scan gauge is a very useful tool. Read/clear codes plus monitor numerous engine parameters.