On Board Diagnosis Logic

These self-diagnoses have the one trip detection logic. 

Fig 1: DTC P1148 And P1168 Condition/Possible Cause Diagnostic Chart

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

DTC P1148 or P1168 is displayed with another DTC for air fuel ratio (A/F) sensor 1. Perform the trouble diagnosis for the corresponding DTC.