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


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)

CHECK ECM TERMINAL VOLTAGE (VC TERMINAL)

REPLACE DIESEL THROTTLE BODY ASSEMBLY

READ VALUE USING INTELLIGENT TESTER

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 0.7 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 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, Gdj150,155.1Kd-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
Ignition switch ON 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
Ignition switch ON 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, Gdj150,155.1Kd-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, Gdj150,155.1Kd-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 RM0000012XK0ARX.html) and initialization (LandCruiser RM000000TIN08CX.html).
HINT:
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)

  1. Disconnect the throttle position sensor 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
    C73-1 (VC) - C91-8 (VCVL)
    		Always
    		Below 1 Ω
    C73-3 (VTA) - C91-3 (VLU)
    		Always
    		Below 1 Ω
    C73-2 (E2) - C91-9 (EVLU)
    		Always
    		Below 1 Ω
    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    C73-1 (VC) or C91-8 (VCVL) - Body ground
    		Always
    		10 kΩ or higher
    C73-3 (VTA) or C91-3 (VLU) - Body ground
    		Always
    		10 kΩ or higher
    C73-2 (E2) or C91-9 (EVLU) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the throttle position sensor connector.

  1. Reconnect the ECM connector.



NG
Go to step 6
OK


2.CHECK ECM TERMINAL VOLTAGE (VC TERMINAL)


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

  1. Disconnect the throttle position sensor connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    C73-1 (VC) - C73-2 (E2)
    		Ignition switch ON
    		4.5 to 5.5 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to throttle position sensor)

  1. Reconnect the throttle position sensor connector.



NG
Go to step 5
OK


3.REPLACE DIESEL THROTTLE BODY ASSEMBLY

  1. Replace the diesel throttle body assembly (for Bank 1 or Bank 2) (LandCruiser RM0000013ZD02OX.html).


NEXT


4.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

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

  1. Clear the DTCs (LandCruiser RM000000PDK1DJX.html).

  1. Enter the following menus: Powertrain / Engine / Data List / Actual Throttle position or Actual Throttle position #2.

  1. Check the movement of the throttle valve when idling the engine after starting it from ignition switch ON.

    OK
    Condition
    		Tester Display
    Ignition switch ON
    		-5 to 5%
    Idling
    		0 to 90%


OK
END

NG
Go to step 5

5.REPLACE ECM

  1. Replace the ECM (LandCruiser RM0000013Z002CX.html).



NEXT
Go to step 7

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.

  1. Clear the DTCs (LandCruiser RM000000PDK1DJX.html).

  1. Turn the ignition switch off.

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

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

  1. Confirm that the DTC is not output again.


NEXT

END