Fail-Safe Mode
WARNING: This page is about a different car, the 2004 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
When the malfunction A or B is detected in the two consecutive trips, the ECM enters fail-safe mode and the MIL lights up.
When the malfunction C is detected even in the 1st trip, the ECM enters fail-safe mode and the MIL lights up.
Courtesy of NISSAN MOTOR CO., U.S.A.