On Board Diagnosis Logic

To judge the malfunction, the output from the heated oxygen sensor 1 is monitored to determine whether the rich output is sufficiently high and whether the lean output is sufficiently low. When both the outputs are shifting to the lean side, the malfunction will be detected.

Fig 1: Graphing Normal & Lean Heated Oxygen Sensor 1 Outputs

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

Fig 2: Identifying DTC P1143 & P1163 Conditions & Possible Causes

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