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SFI SYSTEM, Diagnostic DTC:P2121

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DTC Code DTC Name
P2121 Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance
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DESCRIPTION

Refer to DTC P2120 (Click here).

DTC No. DTC Detection Condition Trouble Area
P2121

Either of following conditions 1 or 2 met for 0.5 seconds (1 trip detection logic)


  • 1. Difference between VPA and VPA2 is less than 0.4 V, or more than 1.2 V. (learned value of accelerator off position)

  • 2. Difference between VPA and VPA2 is greater than or equal to the specified value.

  • Accelerator pedal sensor assembly

  • ECM
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MONITOR DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position sensor has 2 sensor elements and 2 signal outputs: VPA and VPA2. VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that the accelerator pedal position sensor is malfunctioning. The ECM turns on the MIL and stores the DTC.

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MONITOR STRATEGY

Required Sensors/Components Accelerator pedal sensor assembly
Frequency of Operation Continuous
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CONFIRMATION DRIVING PATTERN


  1. Connect the intelligent tester to the DLC3.

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

  3. Clear DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the ignition switch off and wait for at least 30 seconds.

  5. Turn the ignition switch to ON and turn the tester on [A].

  6. Wait for 5 seconds after turning the ignition switch to ON.

  7. Operate the accelerator pedal in accordance with the following procedure [B].


    1. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sens. No. 1 Volt %, and Accel Sens. No.2 Volt %.

    2. Slowly depress the accelerator pedal until Accel Sens. No.1 Volt % is approximately 30% and Accel Sens. No.2 Volt % is approximately 46%, then slowly release the accelerator pedal.

  9. Enter the following menus: Powertrain / Engine and ECT / DTC [C].

  10. Read pending DTCs.

    Tip:

    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  12. Input the DTC: P2121.

  13. Check the DTC judgment result.

    Tester Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    Tip:

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] and [C] again.

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FAIL-SAFE

The accelerator pedal position sensor has 2 (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between the 2 sensor circuits and switches to fail-safe mode. In fail-safe mode, the functioning circuit is used to calculate the accelerator pedal angle to allow the vehicle to continue driving. If both circuits malfunction, the ECM regards the angle of the accelerator pedal as being fully closed. In this case, the throttle valve remains closed as if the engine is idling. If a pass condition is detected and then the ignition switch is turned off, the fail-safe operation stops and the system returns to a normal condition.

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WIRING DIAGRAM

Refer to DTC P2120 (Click here).

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CAUTION / NOTICE / HINT

Tip:

  • This DTC relates to the accelerator pedal sensor assembly.

  • Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions 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, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

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PROCEDURE


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    CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2121)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

    5. Read DTCs.

      Table 1. Result
      Result Proceed to
      DTC P2121 is output A
      DTC P2121 and other DTCs are output B
      Tip:

      If any DTCs other than P2121 are output, troubleshoot those DTCs first.


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


    1. A01VHTNE03

      Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

    5. Read the values displayed on the tester.

      Standard Voltage
      Accelerator Pedal Operation Accel Sensor Out No. 1 Accel Sensor Out No. 2
      Released 0.5 to 1.1 V 1.2 to 2.0 V
      Depressed 2.5 to 4.5 V 3.4 to 4.7 V
      Table 2. Text in Illustration
      *a Accelerator Pedal
      *b Depressed
      *c Released

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    REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY


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


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    CHECK WHETHER DTC OUTPUT RECURS (DTC P2121)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear the DTCs (Click here).

    5. Turn the ignition switch off and wait for at least 30 seconds.

    6. Turn the ignition switch off.

    7. Turn the ignition switch to ON.

    8. Turn the tester on.

    9. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

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

    11. Read DTCs.

      Table 3. Result
      Result Proceed to
      DTC P2121 is output A
      DTC is not output B