Outline Of Diagnosis: Notes

Check if there is a leakage in fuel system or not, and perform the function diagnosis of valve.

Fig 1: Evaporative Emission Control System Diagram

Courtesy of SUBARU OF AMERICA, INC.

In this system diagnosis, check for leakage and valve function is conducted by changing the fuel tank pressure and monitoring the pressure change using the fuel tank pressure sensor. When in 0.04 inch diagnosis, perform in the order of mode Z → mode A → mode B → mode C and mode D; When in 0.02 inch diagnosis, perform in the order of mode A → mode B → mode C → mode D and mode E.