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.

ECM receives two signals from the fuel level sensor circuit.

One is fuel level sensor power supply circuit, and the other is fuel level sensor ground circuit.

This diagnosis indicates the former, to detect open or short circuit malfunction.

Fig 1: On Board Diagnosis Logic Chart

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