Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK ECM (POWER SOURCE OF THROTTLE POSITION SENSOR)

INSPECT THROTTLE POSITION SENSOR VOLTAGE (VLU VOLTAGE)

CHECK DTC OUTPUT

CHECK HARNESS AND CONNECTOR

CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)

CHECK ECM (CHECK RESISTANCE)

REPLACE DIESEL THROTTLE BODY ASSEMBLY

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

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

DTC 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 0.4 to 1.0 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 3.6 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 pieces of information used for EGR control, etc.

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input


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).
  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
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).
  1. Throttle position sensor
  2. Open in E2 circuit
  3. VC and VLU circuits are short-circuited
  4. ECM
HINT:
If DTC P0122 and/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.

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input


WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input


INSPECTION PROCEDURE

NOTICE:
After replacing the ECM, the new ECM needs registration (LandCruiser RM0000012XK0AUX.html) and initialization (LandCruiser RM000000TIN08HX.html).
HINT:
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.
1.CHECK ECM (POWER SOURCE OF THROTTLE POSITION SENSOR)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    C151-29 (VCVL) - C151-20 (EVLU)
    		Engine switch on (IG)
    		4.5 to 5.5 V
    Text in Illustration
    *a
    		Component with harness connected
    (ECM)


NG
Go to step 8
OK


2.INSPECT THROTTLE POSITION SENSOR VOLTAGE (VLU VOLTAGE)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    C151-21 (VLU) - C151-20 (EVLU)
    		Engine switch on (IG)
    		3.6 to 4.2 V
    Text in Illustration
    *a
    		Component with harness connected
    (ECM)


NG
Go to step 4
OK


3.CHECK DTC OUTPUT

  1. Connect the GTS to the DLC3.

  1. Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

  1. Turn the engine switch off.

  1. Turn the engine switch on (IG) for 3 seconds or more.

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

  1. Confirm that the DTC is not output again.

    Result:

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


B
Go to step 8
A


4.CHECK HARNESS AND CONNECTOR


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input

  1. Disconnect the diesel throttle body assembly connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    r5-5 (VC) - r5-3 (E2)
    		Engine switch on (IG)
    		4.5 to 5.5 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Diesel Throttle Body Assembly)

  1. Reconnect the throttle position sensor connector.



NG
Go to step 9
OK


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

  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:

    Tester Connection
    		Condition
    		Specified Condition
    r5-6 (VTA) - C151-21 (VLU)
    		Always
    		Below 1 Ω
    r5-3 (E2) - C151-20 (EVLU)
    		Always
    		Below 1 Ω
    r5-6 (VTA) or C151-21 (VLU) - Body ground and other terminals
    		Always
    		10 kΩ or higher
    r5-3 (E2) or C151-20 (EVLU) - Body ground and other terminals
    		Always
    		10 kΩ or higher

  1. Reconnect the diesel throttle body assembly connector.

  1. Reconnect the ECM connector.



NG
Go to step 9
OK


6.CHECK ECM (CHECK RESISTANCE)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low Input

  1. Disconnect the diesel throttle body assembly connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    r5-5 (VC) - r5-6 (VTA)
    		Engine switch off
    		No short or open
    r5-6 (VTA) - r5-3 (E2)
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Diesel Throttle Body Assembly)

  1. Reconnect the diesel throttle body assembly connector.



NG
Go to step 8
OK


7.REPLACE DIESEL THROTTLE BODY ASSEMBLY

  1. Replace the diesel throttle body assembly (LandCruiser RM0000013ZD02QX.html).



NEXT
Go to step 10

8.REPLACE ECM

  1. Replace the ECM (LandCruiser RM0000013Z002DX.html).



NEXT
Go to step 10

9.REPAIR OR REPLACE HARNESS OR CONNECTOR

  1. Repair or replace the harness or connector.



NEXT
Go to step 10

10.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

  1. Connect the GTS to the DLC3.

  1. Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

  1. Turn the engine switch off.

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

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

  1. Confirm that the DTC is not output again.


NEXT

END