SFI SYSTEM, Diagnostic DTC:P2120, P2122, P2123, P2125, P2127, P2128, P2138

DTC Code DTC Name
P2120 Throttle / Pedal Position Sensor / Switch "D" Circuit
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
P2125 Throttle / Pedal Position Sensor / Switch "E" Circuit
P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
P2138 Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation

CAUTION / NOTICE / HINT

Tech Tips


  • These DTCs relate to the Accelerator Pedal Position (APP) sensor.

  • This ETCS (Electronic Throttle Control System) does not use a throttle cable.

DESCRIPTION

The APP sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type sensor. It uses Hall-effect elements in order to yield accurate signals, even in extreme driving conditions, such as at high speeds as well as very low speeds. The voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0 V and 5 V in proportion to the amount the accelerator pedal is depressed (throttle valve opening angle). A signal from VPA indicates the actual accelerator pedal position (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the APP sensor itself.

The ECM monitors the actual accelerator pedal position (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

A005VPWE38
DTC No. DTC Detection Condition Trouble Area
P2120 VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).

  • APP sensor


  • ECM
P2122 VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1 trip detection logic).

  • APP sensor


  • Open in VCP1 circuit


  • Open or ground short in VPA circuit


  • ECM
P2123 VPA is 4.8 V or higher for 2.0 seconds or more (1 trip detection logic).

  • APP sensor


  • Open in EPA circuit


  • ECM
P2125 VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).

  • APP sensor


  • ECM
P2127 VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1 trip detection logic).

  • APP sensor


  • Open in VCP2 circuit


  • Open or ground short in VPA2 circuit


  • ECM
P2128

Conditions (a) and (b) continue for 2.0 seconds or more (1 trip detection logic):

(a) VPA2 is 4.8 V or higher.

(b) VPA is between 0.4 V and 3.45 V.

  • APP sensor


  • Open in EPA2 circuit


  • ECM
P2138

Condition (a) or (b) continues for 2.0 seconds or more (1 trip detection logic):

(a) The 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.

  • Short between VPA and VPA2 circuits


  • APP sensor


  • ECM

Tech Tips


  • When any of these DTCs are output, check the APP sensor voltage using the intelligent tester. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No.1 and Accel Sensor Out No.2.

    Trouble Area

    Accel Sensor Out No.1

    When AP Released

    Accel Sensor Out No.2

    When AP Released

    Accel Sensor Out No.1

    When AP Depressed

    Accel Sensor Out No.2

    When AP Depressed
    VCP circuit open 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V
    Open or ground short in VPA circuit 0 to 0.2 V 1.2 to 2.0 V 0 to 0.2 V 3.4 to 4.9 V
    Open or ground short in VPA2 circuit 0.5 to 1.1 V 0 to 0.2 V 2.6 to 4.5 V 0 to 0.2 V
    EPA circuit open 4.5 to 4.9 V 4.5 to 4.9 V 4.5 to 4.9 V 4.5 to 4.9 V
    Normal condition 0.5 to 1.1 V 1.2 to 2.0 V 2.6 to 4.5 V 3.4 to 4.9 V

  • Accelerator pedal positions are expressed as voltages.

  • AP stands for Accelerator Pedal.

FAIL-SAFE

When DTC P2120, P2121, P2122, P2123, P2125, P2127, P2128 or P2138 is stored, the ECM enters fail-safe mode. If either of the 2 sensor circuit malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue being driven. If both of the circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles. Fail-safe mode continues until a pass condition is detected and the engine switch is turned off.

WIRING DIAGRAM

A005WK4E01

INSPECTION PROCEDURE

Tech Tips

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.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (ACCEL SENSOR OUT NO.1 AND ACCEL SENSOR OUT NO.2)

    A005UH6E01

    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No.1 and Accel Sensor Out No.2.

    4. Read the value displayed on the tester.

      Standard Voltage
      Accelerator Pedal Operation Accel Sensor Out No.1 Accel Sensor Out No.2
      Released → Depressed → Released 0.5 to 4.5 V 1.2 to 4.9 V
      Difference between Accel Sensor Out No.1 and Accel Sensor Out No.2 is greater than 0.02 V Difference between Accel Sensor Out No.1 and Accel Sensor Out No.2 is greater than 0.02 V

    NG

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

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

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

    A005STRE02
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Accelerator Pedal Position Sensor)
    *2

    Front view of wire harness connector

    (to ECM)

    1. Disconnect the A2 Accelerator Pedal Position (APP) sensor connector.

    2. Disconnect the A40 ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A2-6 (VPA) - A40-55 (VPA) Always Below 1 Ω
      A2-5 (EPA) - A40-59 (EPA)
      A2-4 (VCPA) - A40-57 (VCPA)
      A2-3 (VPA2) - A40-56 (VPA2)
      A2-2 (EPA2) - A40-60 (EPA2)
      A2-1 (VCP2) - A40-58 (VCP2)
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A2-6 (VPA) or A40-55 (VPA) - Body ground Always 10 kΩ or higher
      A2-5 (EPA) or A40-59 (EPA) - Body ground
      A2-4 (VCPA) or A40-57 (VCPA) - Body ground
      A2-3 (VPA2) or A40-56 (VPA2) - Body ground
      A2-2 (EPA2) or A40-60 (EPA2) - Body ground
      A2-1 (VCP2) or A40-58 (VCP2) - Body ground

    4. Reconnect the APP sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (VCPA AND VCP2 VOLTAGE)

    A005UFIE02
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Accelerator Pedal Position Sensor)

    1. Disconnect the A2 APP sensor connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A2-4 (VCPA) - A2-5 (EPA) Engine switch on (IG) 4.5 to 5.5 V
      A2-1 (VCP2) - A2-2 (EPA2)

    3. Reconnect the APP sensor connector.


    NG

    REPLACE ECM Click here

    OK

  4. REPLACE ACCELERATOR PEDAL ASSEMBLY


    1. Replace the accelerator pedal assembly Click here.


    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Clear DTCs Click here.

    4. Start the engine.

    5. Allow the engine to idle for 15 seconds.

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

    7. Read DTCs.

      Result
      Result Proceed to
      DTC P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 output A
      No DTC output B

    B

    END

    A

    REPLACE ECM Click here