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Home >> Nissan-Datsun >> 2004 >> Altima Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Control System - 2.5L >> DTC P2138: App Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body. Refer to "GROUND INSPECTION ".
      Fig 1: Checking Ground Connections
      G02884924Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : GO TO 2.
    2. NG : Repair or replace ground connections.
  2. CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT 
    1. Disconnect accelerator pedal position (APP) sensor harness connector.
    2. Turn ignition switch ON.
      Fig 2: Disconnecting Accelerator Pedal Position (APP) Sensor Harness Connector
      G02884925Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between APP sensor terminal 2 and ground with CONSULT-II or tester.

      Voltage: Approximately 5V 

      Fig 3: Checking Voltage Between APP Sensor Terminal 2 & Ground
      G02884926Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : GO TO  4.
    2. NG : GO TO 3.
  3. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E21, F34
    • Harness for open or short between ECM and accelerator pedal position sensor
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  4. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-I 

    Check voltage between APP sensor terminal 1 and ground with CONSULT-II or tester.

    Voltage: Approximately 5V 

    Fig 4: Checking Voltage Between APP Sensor Terminal 1 & Ground
    G02884927Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : GO TO  10.
    2. NG : GO TO 5.
  5. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-II 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between APP sensor terminal 1 and ECM terminal 91. Refer to Wiring Diagram .

      Continuity should exist. 

    OK or NG

    1. OK : GO TO  7.
    2. NG : GO TO 6.
  6. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E21, F34
    • Harness for open between ECM and accelerator pedal position sensor
    1. : Repair or replace open circuit.
  7. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-III 

    Check the following.

    • Harness for short to power and short to ground, between the following terminals.
    ECM TERMINALS REFERENCE

    ECM terminal Sensor terminal Reference Wiring Diagram
    91 APP sensor terminal 1 WIRING DIAGRAM 
    47 Electric throttle control actuator terminal 1 WIRING DIAGRAM 

    OK or NG

    1. OK : GO TO 8.
    2. NG : Repair short to ground or short to power in harness or connectors.
  8. CHECK THROTTLE POSITION SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG

    1. OK : GO TO  16.
    2. NG : GO TO 9.
  9. REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR 
    1. Replace the electric throttle control actuator.
    2. Perform "THROTTLE VALVE CLOSED POSITION LEARNING ".
    3. Perform "IDLE AIR VOLUME LEARNING ".
    1. >> INSPECTION END 
  10. CHECK APP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Check harness continuity between APP sensor terminal 4, 5 and ground. Refer to Wiring Diagram .

      Continuity should exist. 

    3. Also check harness for short to ground and short to power.

    OK or NG

    1. OK : GO TO  12.
    2. NG : GO TO 11.
  11. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E21, F34
    • Harness for open or short between ECM and accelerator pedal position sensor
    • Harness for open or short between TCM and accelerator pedal position sensor
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  12. CHECK APP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 106 and APP sensor terminal 3, ECM terminal 98 and APP sensor terminal 6. Refer to Wiring Diagram .

      Continuity should exist. 

    3. Also check harness for short to ground and short to power.

    OK or NG

    1. OK : GO TO  14.
    2. NG : GO TO 13.
  13. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E21, F34
    • Harness for open or short between ECM and accelerator pedal position sensor
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  14. CHECK APP SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG

    1. OK : GO TO  16.
    2. NG : GO TO 15.
  15. REPLACE ACCELERATOR PEDAL ASSEMBLY 
    1. Replace accelerator pedal assembly.
    2. Perform "ACCELERATOR PEDAL RELEASED POSITION LEARNING ".
    3. Perform "THROTTLE VALVE CLOSED POSITION LEARNING ".
    4. Perform "IDLE AIR VOLUME LEARNING ".
    1. >> INSPECTION END 
  16. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    1. >> INSPECTION END 
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