4. Check Ho2S1 Connector For Water

1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 1 harness connector.
   Fig 1: Identifying HO2S1 Harness Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check connectors for water.

   Water should not exist. 

OK or NG 

1. OK: GO TO 5.
2. NG: Repair or replace harness or connectors.