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 (APP) 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 set.

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 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.

WIRING DIAGRAM

Refer to DTC P2120 Click here.

CAUTION / NOTICE / HINT

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 (APP) sensor.

PROCEDURE


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


    1. A001F1HE62
      *1 Depressed
      *2 Released

      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 / 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
      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

    OK

    REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY Click here

    NG

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


    1. A0019IRE01
      *1 Front view of wire harness connector: (to Accelerator Pedal Position Sensor)
      *2 ECM Connector

      Disconnect the A36 Accelerator Pedal Position (APP) sensor connector.

    2. Disconnect the A14 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
      A36-6 (VPA) - A14-29 (VPA) Always Below 1 Ω
      A36-5 (EPA) - A14-20 (EPA) Always Below 1 Ω
      A36-4 (VCPA) - A14-23 (VCPA) Always Below 1 Ω
      A36-3 (VPA2) - A14-28 (VPA2) Always Below 1 Ω
      A36-2 (EPA2) - A14-21 (EPA2) Always Below 1 Ω
      A36-1 (VCP2) - A14-22 (VCP2) Always Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      A36-6 (VPA) or A14-29 (VPA) - body ground Always 10 kΩ or higher
      A36-5 (EPA) or A14-20 (EPA) - body ground Always 10 kΩ or higher
      A36-4 (VCPA) or A14-23 (VCPA) - body ground Always 10 kΩ or higher
      A36-3 (VPA2) or A14-28 (VPA2) - body ground Always 10 kΩ or higher
      A36-2 (EPA2) or A14-21 (EPA2) - body ground Always 10 kΩ or higher
      A36-1 (VCP2) or A14-22 (VCP2) - body ground Always 10 kΩ or higher

    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 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. Turn the engine switch on (IG) and turn the tester ON.

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

    7. Enter the following menus: Powertrain / Engine / Data List / All Data / 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. Enter the following menus: Powertrain / Engine / DTC.

    10. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P2121 A
      No output B

    A

    REPLACE ECM Click here

    B

    SYSTEM OK