This website has the recomendations for all fluid changes. smg.toyotapartsandservice.com/index.php
you should change oil on you car every 5000 miles
Each 5k miles.
How to change the oil filter on a 2009 Camry V6?
100K miles transmission oil flush & change.
If you drive normally change it every 5,000 miles if you use Conventional oil or every 8,000 if you use Synthetic.
See topic "Engine Oil Replacement Reminder Light (for vehicles sold in U.S.A.)" on page 124 of your Owner's Manual.
4 Quarts
A 1999 Toyota Camry needs four quarts of oil :-)
The Check Engine Light has nothing to do with oil changes. It is on because the ECU has detected a problem with the emissions system.
Follow the manufactures recommendations or change it every 7,500 miles if you drive normally.
3000 miles
On my 04 Camry that means it's time for an oil change.