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

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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
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CAUTION / NOTICE / HINT

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DESCRIPTION

The accelerator pedal position sensor is integrated with the accelerator pedal bracket and has 2 sensor circuits: VPA1 (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 VPA1 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 VPA1 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 VPA1 circuit and is used to check the accelerator pedal position sensor itself.

The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA1 and VPA2, and controls the throttle actuator according to these signals.

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

  • Accelerator pedal position sensor

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

  • Accelerator pedal position sensor

  • Open in VCPA circuit

  • Open or ground short in VPA1 circuit

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

  • Accelerator pedal position 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)

  • Accelerator pedal position sensor

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

  • Accelerator pedal position 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 more

(b) VPA1 is between 0.4 V and 3.45 V

  • Accelerator pedal position sensor

  • Open in EPA2 circuit

  • ECM
P2138

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

(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

  • Short between VPA and VPA2 circuits

  • Accelerator pedal position sensor

  • ECM
Tip:

When any of these DTCs are set, check the accelerator pedal position sensor voltage by entering the following menus on 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 Areas Accel Sensor Out No. 1 When accelerator pedal Released Accel Sensor Out No. 2 When accelerator pedal Released Accel Sensor Out No. 1 When accelerator pedal Depressed Accel Sensor Out No. 2 When accelerator pedal 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 VPA1 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
Tip:

Accelerator pedal positions are expressed as voltages.

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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 off.

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WIRING DIAGRAM

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INSPECTION PROCEDURE

Tip:

Read freeze frame data using the 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.

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PROCEDURE


  1. Click here

    READ VALUE USING INTELLIGENT TESTER (ACCELERATOR PEDAL POSITION SENSOR)


    1. A017G5YE41

      Connect the intelligent tester to the DLC3.

    2. Turn the ignition 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 values displayed on the tester.

      Standard voltage
      Accelerator Pedal Operation Accel Sensor Out No. 1 Accel Sensor Out No. 2 Difference between Accel Sensor Out No. 1 and Accel Sensor Out No. 2
      Released 0.5 to 1.1 V 1.2 to 2.0 V More than 0.02 V
      Fully Depressed 2.6 to 4.5 V 3.4 to 5.0 V
      Table 1. Text in Illustration
      *a Depressed
      *b Released
      Result
      Result Proceed to
      NG A
      OK B

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


    1. Disconnect the accelerator pedal position sensor connector.

    2. Disconnect the 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
      A19-6 (VPA) - D55-6 (VPA) Always Below 1 Ω
      A19-5 (EPA) - D55-3 (EPA) Always Below 1 Ω
      A19-4 (VCPA) - D55-4 (VCPA) Always Below 1 Ω
      A19-3 (VPA2) - D55-5 (VPA2) Always Below 1 Ω
      A19-2 (EPA2) - D55-1 (EPA2) Always Below 1 Ω
      A19-1 (VCP2) - D55-2 (VCP2) Always Below 1 Ω
      Check for short
      Tester Connection Condition Specified Condition
      A19-6 (VPA) or D55-6 (VPA) - Body ground Always 10 kΩ or higher
      A19-5 (EPA) or D55-3 (EPA) - Body ground Always 10 kΩ or higher
      A19-4 (VCPA) or D55-4 (VCPA) - Body ground Always 10 kΩ or higher
      A19-3 (VPA2) or D55-5 (VPA2) - Body ground Always 10 kΩ or higher
      A19-2 (EPA2) or D55-1 (EPA2) - Body ground Always 10 kΩ or higher
      A19-1 (VCP2) or D55-2 (VCP2) - Body ground Always 10 kΩ or higher

    4. Reconnect the accelerator pedal position sensor connector.

    5. Reconnect the ECM connector.


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    INSPECT ECM (VCPA AND VCP2 VOLTAGE)


    1. A017CWJE97

      Disconnect the accelerator pedal position sensor connector.

    2. Turn the ignition switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      A19-4 (VCPA) - A19-5 (EPA) Ignition switch on (IG) 4.5 to 5.0 V
      A19-1 (VCP2) - A19-2 (EPA2) Ignition switch on (IG) 4.5 to 5.0 V
      Table 2. Text in Illustration
      *a

      Front view of wire harness connector

      (to Accelerator Pedal Position Sensor)

    4. Reconnect the accelerator pedal position sensor connector.


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    REPLACE ACCELERATOR PEDAL ASSEMBLY


    1. Replace the accelerator pedal position sensor (Click here).


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


    1. Connect the intelligent tester to the DLC3.

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

    3. Clear the 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 the DTCs.

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

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    REPLACE ECMClick here

  7. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)

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    REPLACE ECMClick here

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    END