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СИСТЕМА SFI, 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

Tip:

Refer to DTC P2120 (Click here).

DTC Code 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 Position (APP) sensor

  • 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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FAIL-SAFE

The Accelerator Pedal Position (APP) sensor has two (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 two sensor circuits and switches to limp mode. In limp mode, the functioning circuit is used to calculate the accelerator pedal opening angle to allow the vehicle to continue driving. If both circuits malfunction, the ECM regards the opening 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 engine 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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INSPECTION PROCEDURE

Tip:

  • This DTC relates to the Accelerator Pedal Position (APP) sensor.

  • 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, 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 engine switch on (IG).

    3. Turn the tester on.

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

    5. Read DTCs.

      Table 1. Result
      Result Proceed to
      P2121 is output A
      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 (ACCELERATOR POSITION SENSOR)


    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 values displayed on the tester.

      Standard 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 4.75 V

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    REPLACE ACCELERATOR PEDAL


    1. Replace the accelerator pedal 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 engine switch on (IG) and turn the tester on.

    3. Clear DTCs (Click here).

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

    5. Wait for 5 seconds after turning the engine switch on (IG).

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

    7. 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.

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

    9. Read DTCs.

      Table 2. Result
      Result Proceed to
      P2121 is output A
      No DTC is output B

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    GO TO DTC CHARTClick here

  6. Click here

    CHECK FOR INTERMITTENT PROBLEMSClick here

  7. Click here

    SYSTEM OK

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    REPLACE ECMClick here