1. Follow "BEFORE SERVICE PRECAUTION" before performing any work operations to prevent fuel from spilling from the fuel system. (See BEFORE SERVICE PRECAUTION [ZJ, Z6, LF].)
2. Disconnect the negative battery cable.
3. Remove the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION [ZJ, Z6, LF].)
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.