SFI SYSTEM (w/ Secondary Air Injection 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

DESCRIPTION

Tech Tips


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

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

The Accelerator Pedal Position (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, and 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 operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (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 opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

A01BDHYE04
DTC No. DTC Detection Conditions Trouble Areas
P2120

VPA fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more

(1 trip detection logic)

  • Accelerator Pedal Position (APP) sensor

  • ECM
P2122

VPA 0.4 V or less for 0.5 seconds or more when accelerator pedal fully released

(1 trip detection logic)

  • APP sensor

  • Open in VCP1 circuit

  • Open or ground short in VPA circuit

  • ECM
P2123

VPA 4.8 V or more for 2.0 seconds or more

(1 trip detection logic)

  • APP sensor

  • Open in EPA circuit

  • ECM
P2125

VPA2 fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more

(1 trip detection logic)

  • APP sensor

  • ECM
P2127

VPA2 1.2 V or less for 0.5 seconds or more when accelerator pedal 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):


    1. VPA2 4.8 V or more

    2. VPA 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):


    1. Difference between VPA and VPA2 0.02 V or less

    2. VPA 0.4 V or less and VPA2 1.2 V or less

  • Short between VPA and VPA2 circuits

  • APP sensor

  • ECM

Tech Tips

When any of these DTCs are set, check the APP sensor voltage by selecting the following menu items on an intelligent tester: Powertrain / Engine and ECT / Data List / Accel Sensor Out No.1 and Accel Sensor Out No.2.

Trouble Areas

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 5.0 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 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V
Normal condition 0.5 to 1.1 V 1.2 to 2.0 V 2.6 to 4.5 V 3.4 to 5.0 V

Tech Tips


  • Accelerator pedal positions are expressed as voltages.

  • AP denotes for Accelerator Pedal.

MONITOR DESCRIPTION

When either of the voltage outputs of VPA or VPA2 deviates from the standard range, or the difference between the voltage outputs of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction in the APP sensor. The ECM then illuminates the MIL and sets a DTC.

Example:

When the voltage output of VPA drops below 0.4 V for more than 0.5 seconds when the accelerator pedal is fully depressed, DTC P2122 is set.

If the malfunction is not repaired successfully, a DTC is set 2 seconds after the engine is next started.

FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are set, the ECM enters fail-safe mode. If either of the 2 sensor circuits malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue driving. 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 ignition switch is turned to OFF.

WIRING DIAGRAM

A01BEJRE01

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using an intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


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


    1. A01BDFBE10

      Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to the ON position and turn the tester ON.

    3. Select the following menu items: Powertrain / Engine and ECT / Data List / Accel Sensor Out No.1 and Accel Sensor Out No.2.

    4. Read the values displayed on the tester.

      Voltage
      Accelerator Pedal Operations Accel Sensor Out No.1 Accel Sensor Out No.2
      Released 0.5 to 1.1 V 1.2 to 2.0 V
      Depressed 2.6 to 4.5 V 3.4 to 5.0 V

    OK

    CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS) Click here

    NG

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


    1. A01BBRDE01

      Disconnect the B1 Accelerator Pedal Position (APP) sensor connector.

    2. Disconnect the B9 ECM connector.

    3. Measure the resistance.

      Resistance (Check for open)
      Tester Connections Specified Conditions
      VPA (B1-6) - VPA (B9-18) Below 1 Ω
      EPA (B1-5) - EPA (B9-20) Below 1 Ω
      VCPA (B1-4) - VCPA (B9-26) Below 1 Ω
      VPA2 (B1-3) - VPA2 (B9-19) Below 1 Ω
      EPA2 (B1-2) - EPA2 (B9-21) Below 1 Ω
      VCP2 (B1-1) - VCP2 (B9-27) Below 1 Ω
      Resistance (Check for short)
      Tester Connections Specified Conditions
      VPA (B1-6) or VPA (B9-18) - Body ground 10 kΩ or higher
      EPA (B1-5) or EPA (B9-20) - Body ground 10 kΩ or higher
      VCPA (B1-4) or VCPA (B9-26) - Body ground 10 kΩ or higher
      VPA2 (B1-3) or VPA2 (B9-19) - Body ground 10 kΩ or higher
      EPA2 (B1-2) or EPA2 (B9-21) - Body ground 10 kΩ or higher
      VCP2 (B1-1) or VCP2 (B9-27) - Body ground 10 kΩ or higher

    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)


    1. A01BD8LE01

      Disconnect the APP sensor connector.

    2. Turn the ignition switch to the ON position.

    3. Measure the voltage between the terminals of the ECM connector.

      Voltage
      Tester Connections Specified Conditions
      VCPA (B9-26) - EPA (B9-20) 4.5 to 5.0 V
      VCP2 (B9-27) - EPA2 (B9-21) 4.5 to 5.0 V

    4. Reconnect the APP sensor connector.


    NG

    REPLACE ECM

    OK

  4. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY


    NEXT

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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to the ON position and turn the tester ON.

    3. Clear DTCs Click here.

    4. Allow the engine to idle for 15 seconds.

    5. Select the following menu items: Powertrain / Engine and ECT / DTC.

    6. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P2120, P2122, P2123, P2125, P2127, P2128 and P2138 A
      No output B

    B

    END

    A

    REPLACE ECM