my daughter's 2009 sienna has the vsc & trac lights "on".
Tried holding down holding down vsc button to reset,,, did not reset !!!,, lights stay on.
Can anyone offer me any advice how to proceed or what to check to remedy problem.
You mention that check engine light isn't on. This may be a clue, in the sense that when the check engine light is truly not on (as in, the bulb in the cluster is not removed or burnt out - which unfortunately I have encountered in the past), and both the VSC and TRAC lights are on, there is a narrower range of what could have caused it.
Before I go on, i guess an obligatory disclaimer: if you don't happen to have an obd2 reader of any kind, please do consider stopping by autozone, just to see if they can scan it for free.
I had worked on two different '08 Siennas in the past, where the engine light wasn't on, but both the VSC and TRAC lights were on. Obviously I have no idea what code is going to read out of your daughter's Sienna's ECU, but if I had to throw out some suggestions - i have a couple at the top of my mind.
One is a cylinder misfire. This could have occurred just once (not necessarily a recurring issue), and so there is a chance that simply clearing the code (you don't need an obd2 reader for that - just a paperclip), both of the lights will disappear.
Another one is the "zero point calibration" issue. Signals from the individual wheel speed sensors (ABS), as well as the deceleration and yaw sensors differ from what the ECU expects (I believe it expects both a certain voltage and resistance to be within range for each sensor), so both the VSC and TRAC lights may come on.
Without going too far out with what may or may not be the issue here - can you think of any additional information regarding this, even if it doesn't seem relevant on the surface? For example, have the strut towers (shocks, springs, or both) have been worked on recently? Any other suspension work done? Alignment? Anything else that may have taken place prior to the lights coming on?
I hope, of course, this is just a glitch - in the sense that both lights end up clearing and that the issue is not a serious one.