Check Fuel Cap Assembly

(a) Check that the fuel cap is correctly installed.

(b) Confirm that the fuel cap is tightened until a few click sounds are heard.


If an EVAP tester is available, check the fuel cap using the tester.

(1) Remove the fuel cap and install it onto a fuel cap adaptor.

Connect an EVAP tester pump hose to the adaptor, and pressurize the cap to 3.2 to 3.7 kPa (24 to 28 mmHg) using an EVAP tester pump. Seal the adaptor and wait for 2 minutes. Check the pressure. If the pressure is 2 kPa (15 mmHg) or more, the fuel cap is normal.

(c) Reinstall the fuel cap.


Test Results

Suspected Trouble Areas

Proceed To

Fuel cap correctly installed



Fuel cap loose

• Fuel cap improperly installed

• Defective fuel cap

• Fuel cap does not meet OEM specifications


No fuel cap


Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

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