Code 1346 on 2002 toyota sienna

Take it to a car parts store like Advanced Auto to get their free trouble code reading service.

have an auto parts store scan the computer for you.
They most often do this for free (oreilly auto parts and autozone)

Write down the code they give you. Should start with "P" (po442, P1406, etc)

That will be the problem, and they will most likely offer you the part right there.

Toyota is big about EVAP system trouble codes (chech engine lights)

But it could be anything, so this should be an easy fix.

You can even ask them at the parts store where the trouble part is located.

let me know once you find the problem code and I can help more.

eric

You need to have the computer scanned for trouble codes to proceed.
Let me know what you find out.

take it to auto zone and they will tell you what the check engine light code is and
write me back and i will tell you how to fix it

Scheduled Maintenance Services, for most Cars, has to be done at 30K, 60K, and 90K. Toyota recommend to replace the timing belt at 90K Service.
If you wait, one of two things could happen: Nothing, or the belt could break and you would be out thousands to repair the engine instead of a $400 hundred to replace just the belt. If it breaks, there will be damage done to the valves and various other internal components, which will not covered under warranty. The problem is that the Dealer would charge you between $700-$800 because they would also replace the water pump at the same time. Or you can buy the timing belt and change it by your self. To do so, you nee the Haynes Repair Manual specific for your car, or another equivalent manual.
To be safe, have the timing belt changed before the 95k mile mark ...... AND have the water pump replaced with a NEW one.

VSC and TRAC lights will come on any time the check engine light does to reduce engine load. As such these lights being on may have nothing to do with the why the check engine light came on.

If the check engine light is on, a trouble code(s) has been stored in the computer that points to the problem area. The dealer should have read this code(s) to come up with what was wrong. Did the dealer give you a sheet with the trouble code number on it?

The engine may have variable valve timing, if it is not working the engine will revert back to a fail safe condition so that no damage will occur. But it will not be running a peak performance. Or it could be something with the engine timing system.

If you want to do your own checking, start calling autoparts stores to see if one will read the trouble codes for free, it is an easy job. AutoZone will read codes for free.

Hope this help.

very possible you might have a bad harmonic balancer ( crankshaft pulley). have that checked then go from there with replacing it.

need to recheck timing marks if this started when you replaced t-belt.

yes your out on the timing marks, set it to zero remove the top cover and check the marks

Toyota Specific Trouble Codes
P1135 Air/Fuel Sensor Heater Circuit Response. (Bank 1 Sensor 1)
If you have changed the proper sensor then you may need to have the cam shaft looked at.