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Marty, ASE Certified Technician
Category: Car
Satisfied Customers: 54027
Experience:  ASE & Bosch Certified Master Tech. Over 30 years experience.
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message Check fuel filler..engine alarm light lights..american models

Resolved Question:

Dear Mechanic

I get the message Check fuel filler cap.
if this happens twice the engine alarm light lights up and the dealer has to remove this
I replaced the filler cap, but the problem still exists.
what can this be.
It appears to be a problem related to American models, which is my car.
the dealer explained, he did not see this before and has no cure

please help
Submitted: 5 years ago.
Category: Car
Expert:  Marty replied 5 years ago.
Hi, the fuel filler cap message does not necessarily mean that the cap is loose or faulty. The message actually means that there is a large leak in the fuel tank evaporative system. When a large leak occurs the computer assumes that the cap has been left off but the problem can actually be caused by a broken vapor line or a leak in one of the valves in the vapor system. If the fault code has been erased and you continue to get the warning message your fuel tank evaporative system needs to be tested for leakage with a smoke machine. The smoke machine puts smoke into the vapor lines so that any leaks can be found easily by looking for the smoke escaping. Most shops have the ability to perform this test.

Let me know if you have any questions.
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