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Home >> Infiniti >> 2003 >> I35 >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0122: Throttle Position Sensor 2 Circuit Low Input Or DTC P0123: Throttle Position Sensor 2 Circuit High Input >> Diagnostic Procedure
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Diagnostic Procedure

  1. Turn ignition switch off. Loosen and retighten engine ground screws. See Figure .
  2. Disconnect electronic throttle control actuator harness connector. See Fig 1 .
  3. Check voltage between electric throttle control actuator terminal No. 1 and ground. See Fig 2 . Voltage should be about 5 volts. If voltage is to specification, go to next step. If voltage is not to specification, repair open or short circuit to ground or short circuit to power in harness or connectors.
  4. Turn ignition switch off. Check harness continuity between electric throttle control actuator terminal No. 5 and engine ground. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Continuity should exist. Also check harness for short to ground and short to power. If okay, go to step  6 . If not okay, go to next step.
  5. Check joint connector-20 (F71) and harness for open or short circuit between electric throttle control actuator and ECM. Repair as necessary.
  6. Disconnect ECM harness connector. Check harness continuity between ECM terminal No. 84 and electric throttle control actuator terminal No. 2. Continuity should exist. Also check harness for short to ground and short to power. If okay, go to next step. If not okay, repair as necessary.
  7. Reconnect all harness connectors. Perform "Throttle Valve Closed Position Learning". See COMPUTER RELEARN PROCEDURES - INFINITI article. Go to next step.
  8. Turn ignition switch on. Set transmission selector lever to "D" position. Check voltage between ground and ECM terminals No. 83 (TP sensor 1) and No. 84 (TP sensor 2) under conditions in table. See THROTTLE POSITION SENSOR VOLTAGE  table. If voltages are to specification, go to next step. If voltages are not to specification, replace electric throttle control actuator. Perform "Throttle Valve Closed Position Learning" and "Idle Air Volume Learning". See COMPUTER RELEARN PROCEDURES - INFINITI article.
  9. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Disconnecting Electric Throttle Control Actuator Harness Connector
G00251367Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig 2: Identifying Electric Throttle Control Actuator Terminals
G00251368Courtesy of NISSAN MOTOR CO., U.S.A.
THROTTLE POSITION SENSOR VOLTAGE

Terminal No. Voltage
83 (Throttle Position Sensor 1)
Accelerator Pedal Fully Released More Than .36 Volt
Accelerator Pedal Fully Depressed Less Than 4.75 Volts
84 (Throttle Position Sensor 2)
Accelerator Pedal Fully Released Less Than 4.75 Volts
Accelerator Pedal Fully Depressed More Than .36 Volt
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