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Home >> Nissan-Datsun >> 2005 >> Sentra Base, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control System (QG18DE) >> DTC P1122: Electric Throttle Control Function >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten two ground screws on the body.

      Refer to "GROUND INSPECTION ".

      Fig 1: Checking ECM Ground Connections
      G02450143Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK : GO TO 2.
    • NG : Repair or replace ground connections.
  2. CHECK THROTTLE CONTROL MOTOR RELAY SIGNAL CIRCUIT 

    Check voltage between ECM terminal 3 and ground under the following conditions with CONSULT-II or tester.

    Fig 2: Checking Voltage Between ECM Connector Terminal 3 And Ground
    G02450144Courtesy of NISSAN MOTOR CO., U.S.A.
    ECM CONNECTOR TERMINAL 3 VOLTAGE

    Ignition switch Voltage
    OFF Approximately 0V
    ON Battery voltage (11 - 14V)

    OK or NG 

    • OK : GO TO  8.
    • NG : GO TO 3.
  3. CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect throttle control motor relay.
      Fig 3: Locating Throttle Control Motor Relay
      G02450145Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between throttle control motor relay terminals 2, 5 and ground.
      • Voltage: Battery voltage 
      Fig 4: Checking Voltage Between Throttle Control Motor Relay Terminals 2, 5 And Ground
      G02450146Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK : GO TO  5.
    • NG : GO TO 4.
  4. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E10, F48
    • 15A fuse
    • Harness for open or short between throttle control motor relay and fuse
      • : Repair open circuit or short to ground or short to power in harness or connectors.
  5. CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 3 and throttle control motor relay terminal 3. Refer to WIRING DIAGRAM .
      • Continuity should exist. 
    3. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO 6.
    • NG : Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK THROTTLE CONTROL MOTOR RELAY OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check harness continuity between ECM terminal 104 and throttle control motor relay terminal 1. Refer to WIRING DIAGRAM .
      • Continuity should exist. 
    2. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO 7.
    • NG : Repair open circuit or short to ground or short to power in harness or connectors.
  7. CHECK THROTTLE CONTROL MOTOR RELAY 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    • OK : GO TO  11.
    • NG : Replace throttle control motor relay.
  8. CHECK THROTTLE CONTROL MOTOR OUTPUT SIGNAL CIRCUIT FOR OPEN OR SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect electric throttle control actuator harness connector.
    3. Disconnect ECM harness connector.
    4. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
      Fig 5: Electric Throttle Control Actuator Terminal Continuity Chart
      G02450147Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 6: Disconnecting Electric Throttle Control Actuator Harness Connector
      G02450148Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO 9.
    • NG : Repair open circuit or short to ground or short to power in harness or connectors.
  9. CHECK ELECTRIC THROTTLE CONTROL ACTUATOR VISUALLY 
    1. Remove the intake air duct.
    2. Check if foreign matter is caught between the throttle valve and the housing.
    Fig 7: Identifying Electric Throttle Control Actuator
    G02450149Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK : GO TO 10.
    • NG : Remove the foreign matter and clean the electric throttle control actuator inside.
  10. CHECK THROTTLE CONTROL MOTOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    • OK : GO TO 11.
    • NG : GO TO  12.
  11. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG 

    • OK : GO TO 12.
    • NG : Repair or replace harness or connectors.
  12. 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 ".
      • : INSPECTION END