ECD SYSTEM, 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 assembly and detects the opening angle of the throttle valve. This sensor is an electronic sensor and uses Hall-effect elements.

When the throttle valve is fully closed, a voltage of approximately 0.4 to 1.0 V is applied to terminal VLU of the ECM. The voltage applied to terminal VLU of the ECM increases in proportion to the opening angle of the throttle valve and becomes approximately 3.6 to 4.2 V when the throttle valve is fully opened.

The ECM determines the vehicle driving conditions from the signals input to its VLU terminal.

B003KDZE21
*1 Throttle Position Sensor
*2 Magnet
*3 Hall IC
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0122 Throttle / Pedal Position Sensor / Switch "A" Circuit Low Input Throttle position sensor output (VLU) is below 0.2 V for 3 seconds (1 trip detection logic).

  • Throttle position sensor

  • Open or short in VLU circuit

  • Open in VC circuit

  • ECM

 Comes on DTC stored
P0123 Throttle / Pedal Position Sensor / Switch "A" Circuit High Input Throttle position sensor output (VLU) is higher than 4.8 V for 3 seconds (1 trip detection logic).

  • Throttle position sensor

  • Open in E2 circuit

  • VC and VLU circuits are short-circuited

  • ECM

 Comes on DTC stored

Tech Tips

If DTC P0122 and/or P0123 is stored, the following symptoms may appear:


CONFIRMATION DRIVING PATTERN

P0122, P0123
DTC Detection Drive Pattern Ignition switch to ON for 3 seconds

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 of the sensor circuit and illuminates the MIL.

B003QQ2E02

WIRING DIAGRAM

B003MF1E01
*a Throttle Position Sensor

CAUTION / NOTICE / HINT

Note

After replacing the ECM, the new ECM needs registration (See page ) and initialization Click here.

Tech Tips

Read freeze frame data using the GTS. Freeze frame data records 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, and other data from the time the malfunction occurred.

PROCEDURE


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


    1. Disconnect the throttle position sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C113-1 (VC) - C114-18 (VC) Always Below 1 Ω
      C113-3 (VTA) - C115-29 (VLU) Always Below 1 Ω
      C113-2 (E2) - C114-28 (E2) Always Below 1 Ω
      C113-1 (VC) or C114-18 (VC) - Body ground Always 10 kΩ or higher
      C113-3 (VTA) or C115-29 (VLU) - Body ground Always 10 kΩ or higher
      C113-2 (E2) or C114-28 (E2) - Body ground Always 10 kΩ or higher

    4. Reconnect the throttle position sensor connector.

    5. Reconnect the ECM connector.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. CHECK ECM TERMINAL VOLTAGE (VC TERMINAL)


    1. B003RZPC40
      *a

      Front view of wire harness connector

      (to Throttle Position Sensor)

      Disconnect the throttle position sensor connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      C113-1 (VC) - C113-2 (E2) Ignition switch ON 4.5 to 5.5 V

    3. Reconnect the throttle position sensor connector.

      Result
      Proceed to
      OK
      NG

    NG

    GO TO STEP 5 Click here

    OK

  3. REPLACE DIESEL THROTTLE BODY ASSEMBLY


    1. Replace the diesel throttle body assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  4. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.


      Powertrain > Engine > Clear DTCs

    4. Enter the following menus: Powertrain / Engine / Data List / Actual Throttle position.


      Powertrain > Engine > Data List
      Tester Display
      Actual Throttle Position

    5. Check the movement of the throttle valve when idling the engine after starting it from ignition switch to ON.

      OK
      Condition GTS Display
      Ignition switch ON -5 to 5%
      Idling 0 to 90%
      Result
      Proceed to
      OK
      NG

    OK

    END

    NG

  5. REPLACE ECM


    1. Replace the ECM.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 7 Click here

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.

      Result
      Proceed to
      NEXT

    NEXT

  7. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

    2. Clear the DTCs.


      Powertrain > Engine > Clear DTCs

    3. Turn the ignition switch off and wait for 30 seconds or more.

    4. Turn the ignition switch to ON for 3 seconds.

    5. Enter the following menus: Powertrain / Engine / Trouble Codes.


      Powertrain > Engine > Trouble Codes

    6. Confirm that the DTC is not output again.

      Result
      Proceed to
      NEXT

    NEXT

    END