On Board Diagnostic Logic

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.

Malfunction is detected when an excessively low (P0462) or high (P0463) voltage is sent from the sensor is sent to ECM.

Fig 1: DTC Detecting Condition Chart

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