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Home >> Infiniti >> 2004 >> M45 >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P0139, P0159: Ho2S2 >> Diagnostic Procedure >> 3. Check Ho2S2 Ground Circuit For Open And Short
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3. Check Ho2S2 Ground Circuit For Open And Short

  1. Turn ignition switch OFF.
  2. Disconnect heated oxygen sensor 2 harness connector.
    Fig 1: Identifying HO2S2 Harness Connector
    G00795894Courtesy of NISSAN MOTOR CO., U.S.A.
  3. Check harness continuity between HO2S2 terminal 4 and ground. Refer to WIRING DIAGRAM .

    Continuity should exist. 

  4. Also check harness for short to power.

OK or NG 

  1. OK: GO TO 5. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT .
  2. NG: GO TO 4.