ECD SYSTEM(w/o Gear Shift Indicator), 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.

The data is used for EGR control, etc.

A004S99E45
*1 Throttle Position Sensor
*2 Magnet
*3 Hall IC
P0122
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds

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 VC circuit

  • ECM
P0123
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds

Throttle position sensor output (VLU) is more 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
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 more.

  • 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.

A004SPCE12

WIRING DIAGRAM

A004TXIE94
*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 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)

    A004UD7E01
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Throttle Body)
    *2

    Front view of wire harness connector

    (to 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 (Check for Open)
      Tester Connection Condition Specified Condition
      B7-5 (VC) - B39-97 (VCVL) Always Below 1 Ω
      B7-6 (VTA) - B39-119 (VLU) Always Below 1 Ω
      B7-3 (E2) - B39-96 (EVLU) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      B7-5 (VC) or B39-97 (VCVL) - Body ground Always 10 kΩ or higher
      B7-6 (VTA) or B39-119 (VLU) - Body ground Always 10 kΩ or higher
      B7-3 (E2) or B39-96 (EVLU) - Body ground Always 10 kΩ or higher

    4. Reconnect the diesel throttle body assembly connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. CHECK ECM TERMINAL VOLTAGE (VC TERMINAL)


    1. A004S2IE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Throttle Body)

      Disconnect the diesel throttle body assembly connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B7-5 (VC) - B7-3 (E2) Ignition switch ON 4.98 to 5.02 V

    3. Reconnect the diesel throttle body assembly connector.


    NG

    REPLACE ECM Click here

    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 the intelligent tester to the DLC3.

    2. Clear the DTCs Click here.

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

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

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

    6. Read the DTCs.

      Result
      Result Proceed to
      P0122 or P0123 A
      No output B

    B

    END

    A

  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 ignition switch off for 30 seconds or more.

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

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

    6. Confirm that the DTC is not output again.


    NEXT

    END