Toyota Tundra Forum : “Check engine light keeps returning”

If the light is on - there should be codes
If there are NO codes the computer is losing power
If there are codes what are they

Yes, there have been codes everytime. The last time it registered 5 codes and all the suspect parts were diagnosed and all proved to be in perfect working order. For some reason, I think the charcoal cannister keeps appearing as one of the codes.

Clear codes with the battery
Next time the light goes on - Go to autozone Immediately and have the codes read. ( Free Service)
What is happening is one code is causing multiple other ones and makes it very difficult to
diagnose.

I have the extended warrantee so It doesn't cost me a penny to take it to the dealer but its getting to be repetitious. The light came on recently so I took it to Advanced Auto Parts and got a free reading. The code was PO442 vac leak. The gentleman at the store said it is usually associated to a bad gas cap which I had replaced a week after I drove the truck off the dealership about 2 years ago and the problem didn't return till about a year ago.

Forgot to add to my post that I purchased a new gas cap for $16 so hopefully the problem is gone, if not I will be back to the dealership and a complaint to Toyota will be made.

P0442 is a EVAP issue which the dealer if they have the proper equipment should be able to diagnose relatively easily.
If not take it to a certified Emissions repair technician in your area - ( He will have a smoke machine ) and get it fixed and have
Toyota pay the bill  :)

The gentleman at Advance AP also mentioned the smoke test. I'll see what happens with the gas cap. Thanks for your input.

bet you money its the o2 sensor like it is on most vehicles with that mileage........it think it's a conspiracy with car owners to make it come on near 36,000 miles so that you will either buy extended warranty or bring it into the garage to get it fixed and pay 90 dollars for a o2 sensor when you can get online and get a fake o2 sensor for 95 and never replace it again.

Stick to bikes my friend :)