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 in the diesel throttle body assembly and detects the throttle valve (intake shutter) opening angle.

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 judges the vehicle driving conditions from these signals input from terminal VLU, and uses them as one of the conditions for deciding the air fuel ratio correction, power increase correction and fuel cut control, etc.

A01CH7XE10
P0122
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds Open in throttle position sensor circuit for 1 second (1 trip detection logic).

  • Open in throttle position sensor circuit

  • Throttle position sensor (built into diesel throttle body assembly)

  • ECM
P0123
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds Short in throttle position sensor circuit for 1 second (1 trip detection logic).

  • Short in throttle position sensor circuit

  • Throttle position sensor (built into diesel throttle body assembly)

  • ECM

WIRING DIAGRAM

A01CHHUE01

INSPECTION PROCEDURE

Note

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

Tech Tips


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

  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was moving or stationary, whether the engine was warmed up or not, as well as other data recorded at the time of a malfunction.

PROCEDURE


  1. CHECK ECM (VC VOLTAGE)


    1. A01CHEQE75
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      E36-13 (VC) - E36-14 (E2) Ignition switch ON 4.5 to 5.5 V

    NG

    REPLACE ECM Click here

    OK

  2. CHECK ECM (VLU VOLTAGE)


    1. A01CHEQE74
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Throttle Valve Condition Specified Condition
      E36-3 (VLU) - E36-14 (E2) Fully closed 0.4 to 1.0 V
      E36-3 (VLU) - E36-14 (E2) Fully open 3.2 to 4.0 V
      E36-3 (VLU) - E36-14 (E2) Fully closed → Fully open Voltage changes constantly

    NG

    CHECK HARNESS AND CONNECTOR (ECM - THROTTLE POSITION SENSOR) Click here

    OK

    REPLACE ECM Click here

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


    1. Disconnect the ECM connectors.

    2. Disconnect the throttle position sensor connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      T11-1 (VC) - E36-13 (VC) Always Below 1 Ω
      T11-3 (VTA) - E36-3 (VLU) Always Below 1 Ω
      T11-2 (E2) - E36-14 (E2) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      T11-1 (VC) or E36-13 (VC) - Body ground Always 10 kΩ or higher
      T11-3 (VTA) or E36-3 (VLU) - 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 (ECM - THROTTLE POSITION SENSOR)

    OK

  4. REPLACE DIESEL THROTTLE BODY ASSEMBLY (THROTTLE POSITION SENSOR)


    1. Replace the diesel throttle body assembly Click here.


    NEXT

  5. CHECK DTC OUTPUT


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the tester on.

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

    6. Read the DTCs.

      Result
      Result Proceed to
      DTC P0122 and/or P0123 are output A
      DTC is not output B

    B

    END

    A

    REPLACE ECM Click here