LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2008 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P1148 To P2A03 >> DTC P2101: Electric Throttle Control Function >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis 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: Identifying Body Ground Screw
      G05739665Courtesy 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 INPUT SIGNAL CIRCUIT-I
    1. Check voltage between ECM terminal 3 and ground under the following conditions with CONSULT-III or tester.
      VOLTAGE REFERENCE CHART

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

    OK or NG 

    OK: GO TO  9.

    NG: GO TO 3.

    Fig 2: Checking Voltage Between ECM Connector 3
    G05739666Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-I
    1. Turn ignition switch OFF.
    2. Check voltage between ECM terminal 104 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

    OK or NG 

    OK: GO TO  6.

    NG: GO TO 4.

    Fig 3: Checking Voltage Between ECM Terminal 104 And Ground
    G05739667Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-II
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E122.
    3. Check harness continuity between ECM terminal 104 and IPDM E/R terminal 47.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO 5.

    NG: Repair open circuit or short to ground or short to power in harness or connectors.

  5. CHECK FUSE
    1. Disconnect 20A fuse.
    2. Check 20A fuse for blown.

    OK or NG 

    OK: GO TO  8.

    NG: Replace 20A fuse.

  6. CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-II
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E119.
    3. Check harness continuity between ECM terminal 3 and IPDM E/R terminal 6.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO  8.

    NG: GO TO 7.

  7. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E2, F32
    • Harness for open or short between ECM and IPDM E/R

      Repair open circuit or short to ground or short to power in harness or connectors.

  8. CHECK INTERMITTENT INCIDENT

    Refer to "HOW TO CHECK TERMINAL " and "INTERMITTENT INCIDENT ".

    OK or NG 

    OK: Replace IPDM E/R. Refer to "REMOVAL AND INSTALLATION OF IPDM E/R ".

    NG: Repair or replace harness or connectors.

  9. 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 .

      CONTINUITY REFERENCE CHART

      Electric throttle control actuator terminal ECM terminal Continuity
      5 5 Should not exist
      4 Should exist
      6 5 Should exist
      4 Should not exist
    5. Also check harness for short to ground and short to power.
      Fig 4: Identifying Electric Throttle Control Actuator Harness Connector
      G05739668Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 10.

    NG: Repair or replace.

  10. 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.

    OK or NG 

    OK: GO TO 11.

    NG: Remove the foreign matter and clean the electric throttle control actuator inside.

    Fig 5: Identifying Electric Throttle Control Actuator And Throttle Valve
    G05739669Courtesy of NISSAN MOTOR CO., U.S.A.
  11. CHECK THROTTLE CONTROL MOTOR

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 12.

    NG: GO TO  13.

  12. CHECK INTERMITTENT INCIDENT

    Refer to "HOW TO CHECK TERMINAL " and "INTERMITTENT INCIDENT ".

    OK or NG 

    OK: GO TO 13.

    NG: Repair or replace harness or connectors.

  13. 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