2. Check Ho2S2 Ground Circuit For Open And Short

WARNING: This page is about a different car, the 2004 Infiniti M45. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect heated oxygen sensor 2 harness connector.

Fig 1: Identifying HO2S2 Harness Connector
Courtesy of NISSAN MOTOR CO., U.S.A.
Check harness continuity between HO2S2 terminal 4 and ground. Refer to WIRING DIAGRAM .
Continuity should exist.
Also check harness for short to power.

OK or NG

OK: GO TO 4. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT .
NG: GO TO 3.