DTC    P0122    Throttle / Pedal Position Sensor / Switch "A" Circuit Low Input

DTC    P0123    Throttle / Pedal Position Sensor / Switch "A" Circuit High Input

for Preparation Click here


DESCRIPTION

The throttle position sensor is built into 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 3.9 to 4.2 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 inputs used for EGR control, etc.

A128639E05


P0122 
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch is ON
Throttle position sensor output (VLU) is less than 0.2 V for 3 seconds.
(1 trip detection logic)
  1. Throttle position sensor
  2. Open or short in VLU circuit
  3. Open in VC circuit
  4. ECM

P0123 
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch is ON
Throttle position sensor output (VLU) is more than 4.8 V for 3 seconds.
(1 trip detection logic)
  1. Throttle position sensor
  2. Open in E2 circuit
  3. VC and VLU circuits are short-circuited
  4. ECM

Related Data List 
DTC No.
Data List
P0122
  1. Target Throttle Position
  2. Actual Throttle Position
  3. Throttle Sensor Volt %
P0123

HINT:
  1. Throttle position sensor output voltage "Throttle Sensor Volt %" is converted using 5 V = 100 %.
  2. If DTC P0122 or P0123 is stored, the following symptoms may appear:
    1. Intake booming noise
    2. Black smoke
    3. Lack of power
    4. Vibration at engine stop
    5. 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.

A199037E01


WIRING DIAGRAM


A198996E11


INSPECTION PROCEDURE

NOTICE:
When replacing the ECM, the ECM needs Registration and Initialization (Click here).

HINT:
  1. When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the intelligent tester. Then after installing the new ECM, perform all of the initializations/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.
  2. 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.

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


    A199035E01

  1. Disconnect the diesel throttle body assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    B37-5 (VC) - A19-46 (VVLU)
    		Always
    		Below 1 Ω
    B37-6 (VTA2) - A19-45 (VLU)
    		Always
    		Below 1 Ω
    B37-3 (E2) - A19-47 (EVLU)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B37-5 (VC) or A19-46 (VVLU) - Body ground
    		Always
    		10 kΩ or higher
    B37-6 (VTA2) or A19-45 (VLU) - Body ground
    		Always
    		10 kΩ or higher
    B37-3 (E2) or A19-47 (EVLU) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Diesel Throttle Body Assembly)
    *2
    		Front view of wire harness connector
    (to ECM)

  1. Reconnect the diesel throttle body assembly connector.

  1. Reconnect the ECM connector.



NG
Go to step 6
OK


2.CHECK ECM TERMINAL VOLTAGE (VC TERMINAL)


    A199036E01

  1. Disconnect the diesel throttle body assembly connector.

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    B37-5 (VC) - B37-3 (E2)
    		Ignition switch ON
    		4.5 to 5.5 V

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Diesel Throttle Body Assembly)

  1. Reconnect the diesel throttle body assembly connector.



NG
Go to step 5
OK


3.REPLACE DIESEL THROTTLE BODY ASSEMBLY

  1. Replace diesel throttle body assembly (Click here).

  1. Turn the ignition switch to ON.

  1. Turn the ignition switch off and wait for 30 seconds or more.


NEXT


4.READ VALUE USING INTELLIGENT TESTER (ACTUAL THROTTLE POSITION)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch off and wait for 30 seconds or more.

  1. Start the engine and wait for 30 seconds or more.

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

  1. Check the movement of the throttle valve when the ignition switch is turned off from the engine idling.

    HINT:
    When read the values of data list, confirm that PM regeneration is not activating (value of "After Injection Period" is 0) by entering the following menus: Powertrain / Engine and ECT / Data List / After Injection Period.
    If PM regeneration is activating (value of "After Injection Period" is not 0), drive the vehicle until the PM regeneration is complete (value of "After Injection Period" becomes 0).

    Standard:
    Condition
    		Tester Display
    Idling
    		0 to 90%
    Ignition switch off from engine idling
    		Move to 100% once, then return to 0%



NG
Go to step 5
OK

END 

5.REPLACE ECM

  1. Replace the ECM (Click here).



NEXT
Go to step 7

6.REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT


7.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch off and wait for 30 seconds or more.

  1. Start the engine and wait for 30 seconds or more.

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

  1. Confirm that the DTC is not output again.


NEXT

END