Hello, I went to the mechanic last week because my check engine light was on. The mechanic ran a test and said the only problem was that I had a loose fuel filler cap. When I got the car back the check engine light was off because the mechanic had fixed the problem. However the next day the check engine light came on again. I am asuming that the problem is that the fuel filer cap is loose again. What exactlhy is a loose fuel filler cap and how do I fix it so that the check engine light goes off?
Thanks, Billy
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R
Richard Tomkins
1st. The Check Engine light is turned on by the Engine Computer to indicate a failure of some significance in the automobile that must be addressed to prevent damage or maintain specifications and performance. The Transmission Computer can also send a signal to the Engine Computer to turn on this light.
2nd A mechanic with the proper external diagnostic tool can read the failure code that may give an indication as to what has failed. The mechanic should repair the problem and then reset the light.
3rd A loose Fuel Filler Cap can be a cause that the Engine Computer will turn on the Check Engine Light, because the fuel system on the car must be pressurised and a loose cap means the system is not pressurised.
4th The Fuel Filler Cap is what you unscrew to add Fuel to the car and then should securely tighten, so that it clicks when you turn it.
5th If the Fuel Filler Cap is really looses then you had better increase the amount of force you use to secure it in place and ensure that you are installing it correctly. Consult your owners manual.
6th If the Fuel Filler Cap really is secure, then a failure is being logged by the Engine Computer that must be properly interpreted, take the car to a Nissan Dealer.
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David Efflandt
3 clicks should be sufficient.
It could be some other problem with the evaporative emission system, like something cracked or loose hose. I kept getting similar check engine light code one summer (that dealer thought may have been loose filler cap), but each time it was cleared it did not return for a couple of months. Only code I have gotten lately (95 SE) was an obviously failed injector (1st one was under warranty, this was 3rd time 110k mi).
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Filipp Stepanov
Also make sure the engine is off when the car is being fueled.
Transmission
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john smith
V
vander
Buy a new gas cap at Autozone - around 7 bucks (you want the non vented model).
That fixed my check engine light problem.
Also to reset the light, disc>The computer monitors the evaporative system and a loose gas cap can set
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