Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit

Engine. Lexus Is250, Is220D. Gse20 Ale20
2Ad-Fhv Engine Control System. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE OF INTELLIGENT TESTER (ACCELERATOR PEDAL POSITION SENSOR VALUE)

CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)

INSPECT ECM TERMINAL VOLTAGE (VCPA AND VCP2 TERMINALS)

REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

CHECK IF OUTPUT DTC RECURS

DTC P2120 Throttle / Pedal Position Sensor / Switch "D" Circuit

DTC P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input

DTC P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input

DTC P2125 Throttle / Pedal Position Sensor / Switch "E" Circuit

DTC P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input

DTC P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input

DTC P2138 Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation


DESCRIPTION

HINT:
  1. This is the repair procedure for the accelerator pedal position sensor.
  2. This electrical throttle system does not use a throttle cable.
  3. This accelerator pedal position sensor is a non-contact type.
The accelerator pedal position sensor is mounted on the accelerator pedal and detects the opening angle of the accelerator pedal. Since this sensor is electronically controlled with Hall-effect elements, accurate control and reliability can be obtained. It has 2 sensors to detect the accelerator position and a malfunction of the accelerator position sensor.
In the accelerator pedal position sensor, the voltage applied to pedal terminals VPA and VPA2 of the ECM changes between 0 V and 5 V in proportion to the opening angle of the accelerator pedal. The VPA is a signal to indicate the actual accelerator pedal opening angle which is used for the engine control, and the VPA2 is a signal to indicate the information about the opening angle which is used for detecting malfunctions. The ECM judges the current opening angle of the accelerator pedal using signals from terminals VPA and VPA2, and the ECM controls the throttle motor based on these signals.

Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit


DTC No.
DTC Detection Condition
(All of following are 1 trip detection logic)
Trouble Area
P2120
Condition (a) or (b) continues for 0.5 sec. or more:
(a) VPA is 0.4 V or less
(b) VPA is 4.8 V or more
  1. Accelerator pedal position sensor
  2. Accelerator pedal
  3. Accelerator pedal rod (arm) deformed
  4. ECM
P2122
VPA is 0.4 V or less for 0.5 sec. or more when VPA2 output indicates that accelerator pedal is depressed
  1. Accelerator pedal position sensor
  2. Open in VCPA circuit
  3. VPA circuit open or ground short
  4. Accelerator pedal
  5. Accelerator pedal rod (arm) deformed
  6. ECM
P2123
Condition (a) continues for 2.0 sec. or more:
(a) VPA is 4.8 V or more
  1. Accelerator pedal position sensor
  2. Open in EPA circuit
  3. Accelerator pedal
  4. Accelerator pedal rod (arm) deformed
  5. ECM
P2125
Condition (a) or (b) continues for 0.5 sec. or more:
(a) VPA2 is 1.2 V or less
(b) VPA2 is 4.8 V or more
  1. Accelerator pedal position sensor
  2. Accelerator pedal
  3. Accelerator pedal rod (arm) deformed
  4. ECM
P2127
VPA2 is 1.2 V or less for 0.5 sec. or more when VPA output indicates accelerator pedal is opened
  1. Accelerator pedal position sensor
  2. Open in VCP2 circuit
  3. VPA2 circuit open or ground short
  4. Accelerator pedal
  5. Accelerator pedal rod (arm) deformed
  6. ECM
P2128
Conditions (a) and (b) continue for 2.0 sec. or more:
(a) VPA2 is 4.8 V or more
(b) VPA is 0.4 V or more and VPA is 3.45 V or less
  1. Accelerator pedal position sensor
  2. Open in EPA2 circuit
  3. Accelerator pedal
  4. Accelerator pedal rod (arm) deformed
  5. ECM
P2138
Condition (a) or (b) continues for 2.0 sec. or more:
(a) Difference between VPA and VPA2 is 0.02 V or less
(b) VPA is 0.4 V or less and VPA2 is 1.2 V or less
  1. VPA and VPA2 circuits are short circuited
  2. Accelerator pedal position sensor
  3. Accelerator pedal
  4. Accelerator pedal rod (arm) deformed
  5. ECM

HINT:
When DTC P2120, P2122, P2123, P2125, P2127, P2128, or P2138 is detected, check the output voltage of the accelerator pedal position sensor by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Accel Position 1 and Accel Position 2.

-
Accelerator pedal position expressed as voltage output
Accelerator pedal position expressed as voltage output
Accelerator pedal position expressed as voltage output
Accelerator pedal position expressed as voltage output
-
Accelerator pedal released
Accelerator pedal released
Accelerator pedal depressed
Accelerator pedal depressed
Trouble Area
Accelerator Position No. 1
Accelerator Position No. 2
Accelerator Position No. 1
Accelerator Position No. 2
VCP circuit open
0 to 0.2 V
0 to 0.2 V
0 to 0.2 V
0 to 0.2 V
VPA circuit open or ground short
0 to 0.2 V
0.9 to 2.3 V
0 to 0.2 V
3.4 to 5.0 V
VPA2 circuit open or ground short
0.5 to 1.1 V
0 to 0.2 V
3.0 to 4.6 V
0 to 0.2 V
EP circuit open
4.5 to 5.0 V
4.5 to 5.0 V
4.5 to 5.0 V
4.5 to 5.0 V

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit


INSPECTION PROCEDURE

NOTICE:
After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).
1.READ VALUE OF INTELLIGENT TESTER (ACCELERATOR PEDAL POSITION SENSOR VALUE)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch ON (IG) and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Accel Position 1 and Accel Position 2.

  1. Read the values.

    Standard voltage:
    Accelerator Pedal
    		Accel Position 1
    		Accel Position 2
    Released
    		0.5 to 1.1 V
    		0.9 to 2.3 V
    Depressed
    		3.0 to 4.6 V
    		3.4 to 5.0 V


OK
Go to step 5
NG


2.CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit

  1. Disconnect the A26 sensor connector.

  1. Disconnect the A49 ECM connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    VCP2 (A26-1) - VCP2 (A49-56)
    		Below 1 Ω
    EPA2 (A26-2) - EPA2 (A49-58)
    		Below 1 Ω
    VPA2 (A26-3) - VPA2 (A49-54)
    		Below 1 Ω
    VCPA (A26-4) - VCPA (A49-55)
    		Below 1 Ω
    EPA (A26-5) - EPA (A49-57)
    		Below 1 Ω
    VPA (A26-6) - VPA (A49-53)
    		Below 1 Ω
    VCP2 (A26-1) or VCP2 (A49-56) - Body ground
    		10 kΩ or higher
    EPA2 (A26-2) or EPA2 (A49-58) - Body ground
    		10 kΩ or higher
    VPA2 (A26-3) or VPA2 (A49-54) - Body ground
    		10 kΩ or higher
    VCPA (A26-4) or VCPA (A49-55) - Body ground
    		10 kΩ or higher
    EPA (A26-5) or EPA (A49-57) - Body ground
    		10 kΩ or higher
    VPA (A26-6) or VPA (A49-53) - Body ground
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.INSPECT ECM TERMINAL VOLTAGE (VCPA AND VCP2 TERMINALS)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit

  1. Disconnect the A26 sensor connector.

  1. Turn the engine switch ON (IG).

  1. Measure the voltage of the sensor connector.

    Standard voltage:
    Tester Connection
    		Specified Condition
    VCPA (A26-4) - EPA (A26-5)
    		4.5 to 5.5 V
    VCP2 (A26-1) - EPA2 (A26-2)


NG
REPLACE ECM
OK


4.REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

NEXT


5.CHECK IF OUTPUT DTC RECURS

  1. Clear the DTC (Click here).

  1. Start the engine.

  1. Drive the engine at idle for 15 seconds or more.

  1. Read the DTC (Click here).

    Result:

    Display (DTC output)
    		Proceed to
    P2120, P2122, P2123, P2125, P2127, P2128, or P2138 is output again
    		A
    P2120, P2122, P2123, P2125, P2127, P2128, or P2138 is not output
    		B


B
END
A

REPLACE ECM