Probable Cause
WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
Malfunction is detected when ECM does not operate in closed loop. Possible causes are:
- Front Heated Oxygen Sensor (HO2S) circuit open or shorted.
- Defective front HO2S.
- Defective front HO2S heater.