On Board Diagnosis Logic

WARNING: This page is about a different car, the 2004 Infiniti M45. However, it is still accessible from the selected car via links, so may be relevant.

This diagnosis detects very small leaks in the EVAP line between fuel tank and EVAP canister purge volume control solenoid valve, using vapor pressure in the fuel tank in the same way as conventional EVAP small leak diagnosis.

If ECM judges a leak which corresponds to a very small leak, the very small leak P0456 will be detected.

If ECM judges a leak equivalent to a small leak, EVAP small leak P1442 will be detected.

If ECM judges there are no leaks, the diagnosis will be OK.

Fig 1: On Board Diagnosis Logic (1 Of 2)

Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 2: On Board Diagnosis Logic (2 Of 2)

Courtesy of NISSAN MOTOR CO., U.S.A.

CAUTION:

Use only a genuine NISSAN fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may come on.
If the fuel filler cap is not tightened properly, the MIL may come on.
Use only a genuine NISSAN rubber tube as a replacement.