SFI SYSTEM, Diagnostic DTC:P2121

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

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 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 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 the DTC is stored.

FAIL-SAFE

The accelerator pedal position 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 to be driven. If both circuits malfunction, the ECM regards the accelerator pedal as being fully released. 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 normal.

WIRING DIAGRAM

Refer to DTC P2120 Click here.

INSPECTION PROCEDURE

Tech Tips


  • 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.

  • This DTC relates to the accelerator pedal position sensor.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (ACCELERATOR POSITION SENSOR)

    A01DT6HE38
    Text in Illustration
    *a Depressed
    *b Released

    1. Connect the intelligent tester to the DLC3.

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

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / ETCS / Accelerator Position No. 1 and Accelerator Position No. 2.

    4. Read the value displayed on the tester.

      Standard Voltage
      Accelerator Pedal Operation Accelerator Position No. 1 Accelerator Position 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
      Result
      Result Proceed to
      OK A
      NG B

    A

    REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY Click here

    B

  2. 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) - G56-6 (VPA) Always Below 1 Ω
      A19-5 (EPA) - G56-3 (EPA) Always Below 1 Ω
      A19-4 (VCPA) - G56-4 (VCPA) Always Below 1 Ω
      A19-3 (VPA2) - G56-5 (VPA2) Always Below 1 Ω
      A19-2 (EPA2) - G56-1 (EPA2) Always Below 1 Ω
      A19-1 (VCP2) - G56-2 (VCP2) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A19-6 (VPA) or G56-6 (VPA) - Body ground Always 10 kΩ or higher
      A19-5 (EPA) or G56-3 (EPA) - Body ground Always 10 kΩ or higher
      A19-4 (VCPA) or G56-4 (VCPA) - Body ground Always 10 kΩ or higher
      A19-3 (VPA2) or G56-5 (VPA2) - Body ground Always 10 kΩ or higher
      A19-2 (EPA2) or G56-1 (EPA2) - Body ground Always 10 kΩ or higher
      A19-1 (VCP2) or G56-2 (VCP2) - Body ground Always 10 kΩ or higher

    4. Reconnect the accelerator pedal position sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY


    1. Replace the accelerator pedal sensor assembly Click here.


    NEXT

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


    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. 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
      Result Proceed to
      P2121 A
      No output B

    B

    SYSTEM OK

    A

    REPLACE ECM Click here