Diagnostic Procedure For Optical Sensor

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

SYMPTOM: Optical sensor circuit is open or shorted. [50 (driver) or 52 (passenger) is indicated on front air control as a result of conducting self-diagnosis.]

Fig 1: Connecting Optical Sensor Between Front Air Control And BCM

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

CHECK CIRCUIT CONTINUITY BETWEEN OPTICAL SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector and optical sensor connector.
3. Check continuity between optical sensor harness connector M402 terminal 1 (LG) and 2 (SB) and front air control harness connector M50 terminal 40 (LG) and 31 (SB).
  Continuity should exist.
4. Check continuity between optical sensor harness connector M32 terminal 1 (LG) and 2 (SB) and ground.
  Continuity should not exist.
  
  Fig 2: Checking Circuit Continuity Between Optical Sensor And Front Air Control
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 2.
2. NG : Repair harness or connector.
CHECK CIRCUIT CONTINUITY BETWEEN OPTICAL SENSOR AND BCM
1. Turn ignition switch OFF.
2. Disconnect BCM connector and optical sensor connector.
3. Check continuity between optical sensor harness connector M402 terminal 3 (P) and BCM harness connector M18 terminal 18 (P).
  Continuity should not exist.
4. Check continuity between optical sensor harness connector M402 terminal 3 (P) and ground.
  Continuity should not exist.
  
  Fig 3: Checking Continuity Between Optical Sensor Harness Connector Terminal And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : Replace optical sensor.
2. NG : Repair harness or connector.