ECD SYSTEM(for DPF), Diagnostic DTC:P0122 and 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.

A128639E01

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
Table 1. Related Data List

DTC No.

Data List

P0122

Throttle Sensor Volt %

P0123
Tip:

  • 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.

C129051E08

CONFIRMATION DRIVING PATTERN

DTC No.

DTC Detection Drive Pattern

P0122

Ignition switch ON for 3 seconds

P0123

WIRING DIAGRAM

A165731E04

CAUTION / NOTICE / HINT

Note:

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

Tip:

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

      B3-5 (VC) - B76-97 (VCVL)

      Always

      Below 1 Ω

      B3-6 (VTA) - B76-119 (VLU)

      Always

      Below 1 Ω

      B3-3 (E2) - B76-96 (EVLU)

      Always

      Below 1 Ω

      B3-5 (VC) or B76-97 (VCVL) - Body ground

      Always

      10 kΩ or higher

      B3-6 (VTA) or B76-119 (VLU) - Body ground

      Always

      10 kΩ or higher

      B3-3 (E2) or B76-96 (EVLU) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

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

    1. A275086C03

      *a

      Front view of wire harness connector

      (to Throttle Body)

      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

      B3-5 (VC) - B3-3 (E2)

      Ignition switch ON

      4.98 to 5.02 V

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE ECMClick 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 > 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.

      Powertrain > Engine > Trouble Codes

    8. Read the DTCs.

      Result

      Proceed to

      DTC P0122 or P0123 is output

      DTC is not output
    DTC is not output

    END

    DTC P0122 or P0123 is output

  5. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick 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 > 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.

      Powertrain > Engine > Trouble Codes

    8. Confirm that the DTC is not output again.

    Result

    Proceed to

    NEXT
    NEXT

    END