sienna check engine light

2000 Sienna 82500 miles.

Last night the Check Engine light came on while I was driving. There was about a quarter tank of gas in the car. I filled it up and tightened the gas cap well. Told my wife about the gas cap and she said she didn't know to click it several times. I'm hoping that is the problem.

The light has remained on for several On/Off cycles of the van. Google searches tell me it will clear after so many cycles but I see different answers about that. Tomorrow I will take it to Advance Auto and get a free OBD II scan done to find out what it is.

What should I expect to discover and how should the light be reset to see if it returns again?

Reply to
badgolferman
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They will tell you whats up. if it was just the gas cap it would have gone off by now. dont just have them turn it off. take it to your dealership!

Celica00GT

Reply to
Spam Catcher

Although a loose gas cap is the most common cause of a check engine light, you may have some other cause.

Yes, the light should be reset to see if it come on again.

Reply to
Ray O

I have had the code scanned. P0440 Evap Emission Control System. The code has been erased to see if it returns. In five miles I haven't seen it yet.

The Auto Zone mechanic says it might be a charcoal canister tube leak. If this is true, where would I find this canister and what should I look for? Any other thoughts? Thanks.

Reply to
badgolferman

Good news - an Evaporative Emission Control System trouble code is usually caused by a loose or missing gas cap. Evaporative emissions are the vapors that escape from the fuel tank and are controlled with a charcoal canister. The charcoal absorbs the vapors and are then drawn off to be burned in the engine. The fuel system is sealed and as fuel is consumed, a slight vacuum forms. If the charcoal canister develops a leak or the hoses that lead from the fuel tank to the canister develop a leak, the vacuum does not form and a check engine light comes on. Of course, if the gas cap is loose, left off, or has a bad gasket, the vacuum won't form in the tank and the check engine light comes on.

This trouble code will eventually clear itself on its own after the vehicle has been operated a few times after the gas cap has been tightened or you can clear it with the code scanner.

Be sure to tighten the gas cap until it clicks several times - these instructions are probably printed on the gas cap but few people (including me) read the gas cap.

Reply to
Ray O

Thanks for your input, Ray. I am confident your diagnosis is correct. Toyotas seem to be self-healing in most cases.

Reply to
badgolferman

IF the trouble was that the gas cap was not secured, then you should get codes in the family of P0440.

Reply to
Jeff Strickland

P0440 is the code that you should see if the gas cap is not fitted securely.

The guys at AutoZone did you right, they reset the code and sent you on your way.

Reply to
Jeff Strickland

Actually it was a girl holding the scanner...

Reply to
badgolferman

Even better.

Reply to
Jeff Strickland

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