On Board Diagnosis Logic

The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the maximum voltage of the sensor is sufficiently high during the various driving condition such as fuelcut.

Fig 1: DTC P1147, P1167 HO2S2 Identifying Correct Voltage Signal Graph

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

Fig 2: DTC P1147, P1167 HO2S2 - On Board Diagnosis Logic

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