2. Check Harness Continuity

1. Turn ignition switch OFF.
2. Disconnect BCM and auto trunk control unit connector.
3. Check continuity between BCM connector M4 terminal 1 and auto trunk control unit connector B110 terminal 5.
   1. 1 (G/Y) - 5 (G/Y) : Continuity should exist  .
4. Check continuity between BCM connector M4 terminal 1 and ground.
   1. 1 (G/Y) - Ground : Continuity should not exist  .

OK or NG 

1. OK : GO TO 3.
2. NG : Repair or replace harness between BCM and auto trunk control unit.

Fig 1: Checking Harness Continuity

Courtesy of NISSAN MOTOR CO., U.S.A.