LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2008 >> Yaris Base, 2D Hatchback, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Control System (1NZ-FE) >> SFI System >> DTC P2121 Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance >> Inspection Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

HINT:

Read freeze frame data using a Techstream. Freeze frame data record 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.

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2121) 
    1. Connect a Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the tester ON.
    4. Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
    5. Read DTCs.

      Result 

      RESULT CHART

      Display (DTC Output) Proceed To
      P2121 A
      P2121 and other DTCs B

      HINT:

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

    B: GO TO DTC CHART (See  DIAGNOSTIC TROUBLE CODE CHART   ) 

    A: Go to Next Step 

  2. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION NO.1 AND ACCELERATOR POSITION NO.2) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the tester ON.
    4. Select the following menu items: Powertrain / Engine and ECT / Data List / ETCS / Accelerator Position No.1 and Accelerator Position No.2.
    5. Read the values displayed on the tester.

      Standard voltage 

      VOLTAGE SPECIFICATION

      Accelerator Pedal Operations Accelerator Position No.1 Accelerator Position No.2
      Released 0.5 to 1.1V 1.2 to 2.0 V
      Depressed 2.6 to 4.5 V 3.4 to 5.0 V
      Fig 1: Identifying Accelerator Pedal Depressed And Released Position
      G04828218Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: CHECK FOR INTERMITTENT PROBLEMS (See  CHECK FOR INTERMITTENT PROBLEMS   ) 

    NG: Go to Next Step 

  3. REPLACE ACCELERATOR PEDAL 
    1. Replace the accelerator pedal (See REMOVAL  ).
  4. CHECK WHETHER DTC OUTPUT RECURS (DTC P2121) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the tester ON.
    4. Clear DTCs (See DTC CHECK/CLEAR  ).
    5. Start the engine.
    6. Allow the engine to idle for 15 seconds or more.
    7. Fully depress and release the accelerator pedal several times quickly.
    8. Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
    9. Read DTCs.

      Result 

      RESULT CHART

      Display (DTC Output) Proceed To
      P2121 A
      No output B

    B: END 

    A: REPLACE ECM (See  REMOVAL   )