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 Difference between VPA and VPA2 is less than 0.4 V, or more than 1.2 V for 0.5 seconds (1 trip detection logic)

  • Accelerator position sensor

  • ECM

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 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 ignition 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.

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

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 on (IG).

    3. Turn the tester on.

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

    5. Read the DTCs.

      Result
      Display (DTC Output) 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 PEAL POSITION SENSOR)


    1. A017G5YE41
      Text in Illustration
      *a Depressed
      *b Released

      Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG) and turn the tester on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / 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 Difference between Accel Sensor Out No. 1 and Accel Sensor Out No. 2
      Released 0.5 to 1.1 V 1.2 to 2.0 V 0.4 to 1.2 V
      Fully Depressed 2.6 to 4.5 V 3.4 to 5.0 V

    NG

    REPLACE ACCELERATOR PEDAL ASSEMBLY Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  3. REPLACE ACCELERATOR PEDAL ASSEMBLY


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

    3. Clear the DTCs Click here.

    4. Fully depress and release the accelerator pedal.

    5. Check that 20 seconds or more have elapsed since the ignition switch was turned on (IG).

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

    7. Read the DTCs.

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

    B

    END

    A

    REPLACE ECM Click here