Check engine light comes on stating fuel cap not closed but cap is secure . I asked this question 3hrs ago and still no response!!!!!!!

Fuel cap is part of the emission system. If is not put back on correctly your light will come on. Removing and installing correctly will cause the light to go off. Make sure cap is secure each time you fuel up. See if that ends the problem. If not try a new cap.

Hi there:
If the gas cap wasn't on properly then the change in pressure would set off a sensor. Put the cap on right or replace it and if the check engine goes away after a few days that was your problem.



You replaced the cap and it will take quite a few driving cycles for the light to go off if that was the culprit. Try disconnecting the negative battery cable for 5 minutes and that might reset the light.


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You might try turning your switch on and off several times. If the fuel cap is on right then it should eventually go out anyway.

P1133 LEXUS - Air/Fuel Ratio Sensor Circuit Response Malfunction Bank 1 Sensor 1 Possible causes Faulty Air/Fuel Ratio Sensor Bank 1 Sensor 1 Air/Fuel Ratio Sensor Bank 1 Sensor 1 harness is open or shorted Air/Fuel Ratio Sensor Bank 1 Sensor 1 circuit poor electrical conection Check exaust integrity

I am not sure I understand what you are asking but I will tell you that is you have a faulty fuel cap or a leaking fule filler neck, this can cause a check engine light to come on. I have seen people leave the fuel cap too loose and the light come on then Screw it tight and the light goes off. Hope this helps

this is normal, you should not have engine running when re-fueling, fuel gauge moves very slowly if key is on while fueling, turn key off and then on and should read proper level.

I had check engine light and TRAC OFF. OBD-II MIL code was P1133 which is Air Fuel Ratio Sensor Response Malfunction and scanned by AutoZone. After disconnecting the battery for 10-15 minutes, the lights went off. I cleaned the gas cap and tightened it firmly. For the last 400 miles, the lights have not come back. When scanning using Snap-on one, no code was detected. I think gas cap was the reason for the lights.

Hi:
The check fuel cap light is tripped when your cap has been loose or off, and the engine is running. Often you need to have the light reset by a code scanner. If you have checked the cap and it is secure, if you reset the code and it comes back, you possibly need a new gas cap.

Have you checked your fuel cap? A loose or leaking fuel cap will trigger an EVAP code. I would start with a new fuel cap, and have your local autozone, or checker, or automotive store clear the check engine light after you replace the fuel cap. Hope this helps

The fuel system is a pressurized system designed for optimum environmental protection. If the fuel cap is loose it will trigger the light to come on. If it is coming on all the time and you can turn it off by tightening the fuel cap, it's probably time for a new fuel cap. The internal pressure relief valve in the fuel cap itself may have gotten old and is not holding the right amount of pressure or is vibrating loose. Try replacing the fuel cap and seal, and see if this fixes the problem. Make sure you bring the old one in with you to the auto parts store so they can make sure it is an exact match. If the fuel cap is worn out, it may not pass state inspection. (I'm not sure if your state checks for that, but NJ does) Good luck and don't forget to rate! Thank you!