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 lean output is sufficiently low. When both the outputs are shifting to the rich side, the malfunction will be detected.

Fig 1: Graphing Heated Oxygen Sensor 1 (With & W/O Malfunction)

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

Fig 2: Identifying DTC P1144 & P1164 Conditions & Possible Causes

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