LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2003 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1122: Electric Throttle Control Performance Problem >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. Turn ignition off. Loosen and retighten 2 engine ground bolts. See Figure . Disconnect ECM harness connector. See Figure . Check continuity between engine ground and ECM harness connector terminal No. 107 (Black wire). See Figure . Continuity should exist. Also, check circuit for short to voltage. If problem is found, repair as necessary. If problem is not found, go to next step.
  2. Reconnect ECM harness connector. Measure voltage between ground and ECM terminal No. 102 (Red wire) by backprobing. Voltage should be about zero volts. Turn ignition on. Battery voltage should exist. If voltage is as specified, go to step  11 . If voltage is not as specified, go to next step.
  3. Turn ignition off. Remove throttle control motor relay. See Fig 1 . Measure voltage between ground and throttle control motor relay harness connector terminals No. 2 and 5 (White/Green wires). See Fig 2 . If battery voltage exists, go to step  5 . If battery voltage does not exist, go to next step.
  4. Check the following:
    • Check fuse No. 63 (15-amp) located in fuse and fusible link box on left side of engine compartment.
    • Check for open or short between throttle control motor relay and fuse.

    Repair as necessary.

  5. Disconnect ECM harness connector. Check continuity of Red wire between throttle control motor relay harness connector terminal No. 3 and ECM harness connector terminal No. 102. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  7 .
  6. Check the following:
    • Check for poor connection at Black, 8-pin connector F18 terminal No. 5 (Red wire). See Figure . Connector F18 is located on left side of engine compartment. See Figure .
    • Check for open or short between throttle control motor relay and ECM.

    Repair as necessary.

  7. Check continuity between throttle control motor relay harness connector terminal No. 1 (Blue/Orange wire) and ECM harness connector terminal No. 26 (Orange wire). Continuity should exist. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  9 .
  8. Check the following:
    • Check for poor connection at Super Multiple Junction (SMJ) connector M15 terminal 15D (Orange wire). See Figure . SMJ connector M15 is located under left side of instrument panel. See Figure .
    • Check for open or short between throttle control motor relay and ECM.
    • Check for poor connection at White, 18-pin connector F53 terminal No. 10 (Orange wire). See Figure . Connector F53 is located near ECM. See Figure .

    Repair as necessary.

  9. Using jumper wires, apply battery voltage between throttle control motor relay terminals No. 1 and 2. See Fig 2 . Check continuity between terminals No. 3 and 5. Continuity should exist. Remove jumper wires. Continuity should not exist. If continuity is as specified, go to next step. If continuity is not as specified, replace throttle control motor relay.
  10. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
  11. Turn ignition off. Disconnect electric throttle control actuator harness connector. See Figure . Disconnect ECM harness connector. Check continuity of Yellow wire between electric throttle control actuator harness connector terminal No. 6 and ECM harness connector terminal No. 101, and Brown wire between electric throttle control actuator harness connector terminal No. 3 and ECM harness connector terminal No. 103. See Figure . Also, check circuits for short to ground, short to voltage or short together. If problem is found, repair as necessary. If problem is not found, go to next step.
  12. Remove air intake duct. Check for foreign matter between throttle valve and throttle housing. If foreign matter is found, remove foreign matter, and clean throttle housing. If foreign matter is not found, go to next step.
  13. Measure resistance between electric throttle control actuator terminals No. 3 and 6. See Fig 3 . Resistance should be 1-15 ohms at 77°F (25°C). If resistance is as specified, go to next step. If resistance is not as specified, replace electric throttle control actuator. Perform throttle valve closed position learning and idle air volume learning. See PROGRAMMING  .
  14. Check for intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. If problem is found, repair as necessary. If problem is not found, go to next step.
  15. Replace electric throttle control actuator. Perform throttle valve closed position learning and idle air volume learning. See PROGRAMMING  .
Fig 1: Locating ECM Relay, Park/Neutral Position Relay & Throttle Control Motor Relay
G00103818Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Identifying Throttle Control Motor Relay Terminals
G00103714Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 3: Testing Electric Throttle Control Actuator
G00103819Courtesy of NISSAN MOTOR CO., U.S.A.
scientia non olet · About LEMON Manuals