Could be that it just needs reset. Codes remain until reset. Also it could be a bad or failing oil pressure switch which is like a $10 dollar part. As long as you don't see oil dripping out the issue may not be serious but the vechicle is 21 years old.
Thank you. I know the vehicle is old, however, we are just not in the position to purchase any vehicle that cost much, as we are in failing health and the only income that we have is not much because we live on disability.The vehicle seems good otherwise and is perfect for our mobility issues. We just cannot afford to make a huge mistake, but we do need transportation, and of course there is a risk involved with any vehicle of that age. It has a good reputation for being a good high mileage vehicle and we cannot afford much else. It does not look as if it has been abused and seems to be in good shape otherwise. Thank you for your help.
well, the one light for oil comes on every 3k miles. Using a long chop stick poke through the hole in the clear plastic cover over the dash area and press the little button in there to reset the 'change oil' light.
If the 'oil level' light is on see this link: http://www.toyotanation.com/forum/85-previa-forum/331202-engine-oil-level-light.html
also notice the overflow oil container under the hood and fill it if necessary.