ECD SYSTEM (w/o DPF), Diagnostic DTC:P0122, P0123

DTC Code DTC Name
P0122 Throttle / Pedal Position Sensor / Switch "A" Circuit Low Input
P0123 Throttle / Pedal Position Sensor / Switch "A" Circuit High Input

DESCRIPTION

The throttle position sensor is mounted on the diesel throttle body and detects the opening angle of the throttle valve. This sensor is an electronic sensor and uses Hall-effect elements.

The ECM determines the vehicle's driving conditions from the signals input to its VLU terminal. The data is one of the inputs used for EGR control, etc.

A01BCIME05
DTC No. DTC Detection Condition Trouble Area
P0122

Throttle position sensor output (VLU) is less than 0.2 V

(1 trip detection logic)

  • Throttle position sensor (Diesel throttle body assembly)

  • Open or short in throttle position sensor circuit

  • ECM
P0123

Throttle position sensor output (VLU) is more than 4.8 V

(1 trip detection logic)

  • Throttle position sensor (Diesel throttle body assembly)

  • Open or short in throttle position sensor circuit

  • ECM

MONITOR DESCRIPTION

When the output voltage of the throttle position sensor deviates from the normal operating range (between 0.2 V and 4.8 V) for more than 3 seconds, the ECM interprets this as a malfunction in the sensor circuit and illuminates the MIL.

A01BCSBE05

WIRING DIAGRAM

A01BHZSE02

INSPECTION PROCEDURE

Note

After replacing the ECM, the new ECM needs registration Click here and initialization Click here.

Tech Tips


  • If different DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.

  • Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)


    1. A01BF0WE11

      Disconnect the D1 and D3 ECM connectors.

    2. Disconnect the D50 throttle position sensor connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      VC (D1-18) - VC (D50-1) Below 1 Ω
      VLU (D3-29) - VTA (D50-3) Below 1 Ω
      E2 (D1-28) - E (D50-2) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      VC (D1-18) or VC (D50-1) - Body ground 10 kΩ or higher
      VLU (D3-29) or VTA (D50-3) - Body ground 10 kΩ or higher
      E2 (D1-28) or E (D50-2) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT DIESEL THROTTLE BODY ASSEMBLY (VC VOLTAGE)


    1. A01BEIME05

      Disconnect the D50 throttle position sensor connector.

    2. Turn the ignition switch ON.

    3. Measure the voltage of the throttle position sensor connector.

      Standard voltage
      Tester Connection Specified Condition
      VC (D50-1) - E (D50-2) 4.5 to 5.5 V

    NG

    REPLACE ECM

    OK

  3. REPLACE DIESEL THROTTLE BODY ASSEMBLY


    1. Replace the diesel throttle body assembly Click here.


    NEXT

  4. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester ON.

    3. Select the following menu items: Powertrain / Engine / DTC / Clear.

    4. Clear DTCs.

    5. Start the engine.

    6. Allow the engine to idle for 60 seconds or more.

    7. Accelerate the engine quickly from idling to 2,500 rpm repeatedly for 30 seconds.

    8. Select the following menu items: Powertrain / Engine / DTC.

    9. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P0122 and/or P0123 A
      No output B

    B

    SYSTEM OK

    A

    REPLACE ECM