Diagnostic Procedure For In-Vehicle Sensor

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM: In-vehicle sensor circuit is open or shorted. (44, 46 or DTC B2578, B2579) is indicated on front air control as a result of conducting self-diagnosis.

Fig 1: Diagnostic Procedure For In-Vehicle Sensor

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

CHECK IN-VEHICLE SENSOR CIRCUIT
Are diagnostic codes 44, 46 or DTC B2578, B2579 present?

YES or NO
- YES: GO TO 6.
- NO: GO TO 2.
CHECK VOLTAGE BETWEEN IN-VEHICLE SENSOR AND GROUND
1. Disconnect in-vehicle sensor connector.
2. Turn ignition switch ON.
3. Check voltage between in-vehicle sensor harness connector M32 terminal 4 (LG/R) and ground.
  - 4 - Ground: Approx. 5V.
OK or NG
- OK: GO TO 3.
- NG: GO TO 5.
Fig 2: Checking Voltage Between In-Vehicle Sensor Harness Connector M32 Terminal 4 (LG/R) And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between in-vehicle sensor harness connector M32 terminal 1 (V/R) and front air control harness connector M49 terminal 21 (V/R).
  - 1 - 21: Continuity should exist.
OK or NG
- OK: GO TO 4.
- NG: Repair harness or connector.
Fig 3: Checking Continuity Between In-Vehicle Sensor Harness Connector M32 Terminal 1 And Front Air Control Harness Connector M49 Terminal 21
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK IN-VEHICLE SENSOR
Refer to "INTAKE SENSOR CIRCUIT ".

OK or NG
- OK:
  1. Replace front air control. Refer to "FRONT AIR CONTROL ".
  2. Go to "A/C SYSTEM SELF-DIAGNOSIS FUNCTION " and perform self-diagnosis.
- NG:
  1. Replace in-vehicle sensor. Refer to "IN-VEHICLE SENSOR ".
  2. Go to "A/C SYSTEM SELF-DIAGNOSIS FUNCTION " and perform self-diagnosis.
CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between in-vehicle sensor harness connector M32 terminal 4 (LG/R) and front air control harness connector M50 terminal 32 (LG/R).
  - 4 - 32: Continuity should exist.
4. Check continuity between in-vehicle sensor harness connector M32 terminal 4 (LG/R) and ground.
  - 4 - Ground Continuity should not exist.
OK or NG
- OK:
  1. Replace front air control. Refer to "FRONT AIR CONTROL ".
  2. Go to self-diagnosis "A/C SYSTEM SELF-DIAGNOSIS FUNCTION " and perform self-diagnosis.
- NG: Repair harness or connector.
Fig 4: Checking Continuity Between In-Vehicle Sensor Harness Connector M32 Terminal 4 And Front Air Control Harness Connector M50 Terminal 32
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR MOTOR AND FRONT AIR CONTROL (SELF-DIAGNOSIS CODES 44, 46 OR DTC B2578, 2579)
1. Turn ignition switch OFF.
2. Disconnect front air control connector and in-vehicle sensor connector.
3. Check continuity between in-vehicle sensor harness connector M32 terminal 2 (O/B) and 3 (BR/Y) and front air control harness connector M50 terminal 44 (O/B) and 43 (BR/Y).
  - 2 - 44: Continuity should exist.
  - 3 - 43: Continuity should exist.
4. Check continuity between in-vehicle sensor harness connector M32 terminal 2 (O/B) and 3 (BR/Y) and ground.
  - 2, 3 - Ground: Continuity should not exist.
OK or NG
- OK:
  1. Replace front air control. Refer to "FRONT AIR CONTROL ".
  2. Go to "A/C SYSTEM SELF-DIAGNOSIS FUNCTION " and perform self-diagnosis.
- NG: Repair harness or connector.
Fig 5: Checking Continuity Between In-Vehicle Sensor Harness Connector M32 Terminal 2, 3 And Front Air Control Harness Connector M50 Terminal 44 And 43
Courtesy of NISSAN MOTOR CO., U.S.A.