SFI SYSTEM (w/o Secondary Air Injection System), Diagnostic DTC:P2121

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

DESCRIPTION

Tech Tips

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 more than or equal to the specified value.

  • Accelerator pedal position sensor

  • ECM

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 voltage outputs 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 the DTC is set.

FAIL-SAFE

The accelerator pedal position sensor has 2 sensor circuits: Main and Sub.

If either circuit malfunctions, the ECM limits the engine output.

If both circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles.

WIRING DIAGRAM

Refer to DTC P2120 Click here.

INSPECTION PROCEDURE

Tech Tips


  • This DTC relates to the accelerator pedal position 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.

PROCEDURE


  1. CHECK FOR 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 intelligent tester on.

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

    5. Read the DTCs.

      Result
      Result Proceed to
      P2121 is output A
      P2121 and other DTCs are output B

      Tech Tips

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


    B

    GO TO DTC CHART Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (ACCELERATOR PEDAL POSITION SENSOR)

    A01BHDVE02
    Text in Illustration
    *a Depressed
    *b Released

    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent 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 intelligent 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 2.6 to 4.5 V 3.4 to 4.7 V

    NG

    REPLACE ACCELERATOR PEDAL ROD ASSEMBLY Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  3. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY


    1. Replace the accelerator pedal rod assembly Click here.


    NEXT

  4. CHECK WHETHER DTC OUTPUT RECURS (DTC P2121)


    1. Connect the intelligent tester to the DLC3.

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

    3. Clear the DTCs Click here.

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

    5. Turn the ignition switch to ON.

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

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

    8. 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. Read the DTCs.

      Result
      Result Proceed to
      P2121 is output A
      No DTC is output B

    B

    END

    A

    REPLACE ECM Click here