Review on NITOYO Locking Gas Cap: Securely Protect Your Fuel with Key Cover Replacement for 10504 and Compatible Models - Express, Silverado, Suburban, Tahoe, Toyota Tacoma, Tundra, 4Runner, Scion, Honda Accord, Civic, Cadillac, Nissan and Mazda by Jeff Pfaff

I have tried several times to properly close and seal. VERY difficult to lock and unlock. ALSO because it didn't close or didn't close tightly, the fuel cap light came on AND immediately afterwards the check engine light came on. Before that the car was in excellent condition, there were no problems. I am SO GRATEFUL that I kept my old gas cap just in case. I replaced it quickly, and when I took it to the mechanic without telling him anything about the gas cap, the diagnostic codes came back saying it was a stored code (meaning I fixed the [gas cap] problem), but usually the codes are related to an emissions leak. I asked if this could be because the gas cap is not properly closed and they said yes, 100%. And my light never came on again! This is an expensive test and reset code. Luckily the mechanic did me a favor. DO NOT USE this product. It will cost you!