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 1 causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the minimum voltage of sensor is sufficiently low during the various driving condition such as fuel-cut.

Fig 1: Output Signal Graph

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

Fig 2: DTCP1146, P1166 HO2S2 -Detecting Condition And Possible Cause Table

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