ECD SYSTEM (w/ 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 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 0.7 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.

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

A00O84SE01
P0122
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Engine switch on (IG) for 3 seconds 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
P0123
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Engine switch on (IG) for 3 seconds 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

Tech Tips

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


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.

A00O5D5E09

WIRING DIAGRAM

A00O2VVE01

INSPECTION PROCEDURE

Note


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

  • After replacing the fuel supply pump assembly, the ECM needs initialization Click here.

  • After replacing an injector assembly, the ECM needs registration Click here.

Tech Tips

Read freeze frame data using the intelligent tester. 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 (Check for Open)
      Tester Connection Condition Specified Condition
      C73-1 (VC) - C91-8 (VCVL) Always Below 1 Ω
      C73-3 (VTA) - C91-3 (VLU) Always Below 1 Ω
      C73-2 (E2) - C91-9 (EVLU) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      C73-1 (VC) or C91-8 (VCVL) - Body ground Always 10 kΩ or higher
      C73-3 (VTA) or C91-3 (VLU) - Body ground Always 10 kΩ or higher
      C73-2 (E2) or C91-9 (EVLU) - Body ground Always 10 kΩ or higher

    4. Reconnect the throttle position sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. CHECK ECM TERMINAL VOLTAGE (VC TERMINAL)


    1. A00O4ETE11
      Text in Illustration
      *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
      C73-1 (VC) - C73-2 (E2) Engine switch on (IG) 4.5 to 5.5 V

    3. Reconnect the throttle position sensor connector.


    NG

    REPLACE ECM Click here

    OK

  3. REPLACE DIESEL THROTTLE BODY ASSEMBLY


    1. Replace the diesel throttle body assembly Click here.


    NEXT

  4. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the intelligent tester on.

    3. Clear the DTCs Click here.

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

    5. Check the movement of the throttle valve when idling the engine after starting it from engine switch on (IG).

      OK
      Condition Tester Display
      Engine switch on (IG) -5 to 5%
      Idling 0 to 93%

    OK

    END

    NG

    REPLACE ECM Click here

  5. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT

  7. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Clear the DTCs Click here.

    3. Turn the engine switch off.

    4. Turn the engine switch on (IG) for 3 seconds.

    5. Enter the following menus: Powertrain / Engine and ECT / DTC.

    6. Confirm that the DTC is not output again.


    NEXT

    END