Possible Causes

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 HO2S1 response time is too long. Possible causes are:

HO2S1 circuit open or shorted.
Defective HO2S1.
Defective HO2S1 heater.
Fuel pressure incorrect.
Defective injectors.
Intake air leaks.
Exhaust leaks.
Defective PCV valve.
Defective Mass Airflow (MAF) sensor.

NOTE: Before proceeding, ensure ambient temperature is more than 14°F (-10°C) and battery voltage is more than 11 volts at idle.