1. Follow "BEFORE SERVICE PRECAUTION" before performing any work operations to prevent fuel from spilling from the fuel system. (See BEFORE SERVICE PRECAUTION.)
2. Disconnect the negative battery cable.
3. Remove the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION.)
4. Perform the following procedure to verify the fuel tank airtightness.
5. Plug the fuel pump unit pipe and port B.
6. Level the fuel tank.
7. Apply a pressure of 3 kPa {22 mmHg, 0.8 inHg} to port A and wait for a while.
8. With the pressure still applied, verify that there is airflow from port C and the pressure is 0-3 kPa {0-22 mmHg, 0-0.8 inHg}.
9. Apply a pressure of -0.5 kPa {-3.7 mmHg, -0.1 inHg} to port A and wait for a while.
10. With the pressure still applied, verify that there is airflow from port C and the pressure is 0- -0.5 kPa {0- -3.7 mmHg, 0- -0.1 inHg}.
11. Apply a pressure of 3 kPa {22 mmHg, 0.8 inHg} to port A and wait for a while.
12. With the pressure still applied, verify that there is no airflow from port C.