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 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 0.7 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 3.5 to 4.0 V when the throttle valve is fully opened.

This data is used for EGR control, etc.

A012JOUE01
*1 Magnet
*2 Hall IC
*3 Throttle Position Sensor
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 less than 0.2 V for 3 seconds (1 trip detection logic).

  • Throttle position sensor

  • Open or short in VLU circuit

  • Open in VCVL circuit

  • ECM

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

  • Throttle position sensor

  • Open in EVLU circuit

  • VCVL and VLU circuits are short-circuited

  • ECM

 Comes on DTC stored
Related Data List
DTC No. Data List
P0122 Throttle Sensor Volt %
P0123

Tech Tips


  • Throttle Sensor Volt %: Throttle position sensor output voltage is converted using 5 V = 100%.

  • When fully closed: 14% or less.

  • When fully open: 70% or higher.

  • When the ignition switch is turned from off to ON, the throttle valve fully opens once.

  • When the ignition switch is turned from ON to off, the throttle valve fully closes once.

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


    • Intake booming noise

    • Black smoke

    • Lack of power

    • Vibration at engine stop

    • Turbo overspeed, turbo damage

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.

A012GNEE08

CONFIRMATION DRIVING PATTERN

DTC No. DTC Detection Drive Pattern
P0122 Ignition switch ON for 3 seconds
P0123

WIRING DIAGRAM

A012K8KE01
*a Throttle Position Sensor (Built into Diesel Throttle Body Assembly)

CAUTION / NOTICE / HINT

Note

After replacing the ECM, the new ECM needs registration (Click here) 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 diesel throttle body assembly 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
      B25-5 (VC) - B164-97 (VCVL) Always Below 1 Ω
      B25-6 (VTA) - B164-119 (VLU) Always Below 1 Ω
      B25-3 (E2) - B164-96 (EVLU) Always Below 1 Ω
      B25-5 (VC) or B164-97 (VCVL) - Body ground Always 10 kΩ or higher
      B25-6 (VTA) or B164-119 (VLU) - Body ground Always 10 kΩ or higher
      B25-3 (E2) or B164-96 (EVLU) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF THROTTLE POSITION SENSOR)


    1. A012FQ7C04
      *a

      Front view of wire harness connector

      (to Diesel Throttle Body Assembly)

      Disconnect the diesel throttle body assembly connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      B25-5 (VC) - B25-3 (E2) Ignition switch ON 4.98 to 5.02 V
      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. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs

    5. Turn the ignition switch off for 30 seconds or more.

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

    7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    8. Read the DTCs.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Result Proceed to
      DTC P0122 or P0123 is output A
      DTC is not output B

    B

    END

    A

  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. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs

    5. Turn the ignition switch off for 30 seconds or more.

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

    7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    8. Confirm that the DTC is not output.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Proceed to
      NEXT

    NEXT

    END