SFI SYSTEM (w/o Secondary Air Injection System), Diagnostic DTC:P2121/19

DTC Code DTC Name
P2121/19 Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance

DESCRIPTION

Tech Tips

This DTC relates to the Accelerator Pedal Position (APP) sensor.

Refer to DTC P2120 Click here.

DTC No. DTC Detection Conditions Trouble Areas
P2121/19

  • Conditions (a) and (b) continue for 0.5 seconds:


    1. Difference between VPA and VPA2 exceeds threshold

    2. IDL is OFF

  • Accelerator pedal position sensor circuit

  • 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 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 are malfunctioning, 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 to 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 an 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. READ VALUE USING INTELLIGENT TESTER (ACCEL POS #1 AND ACCEL POS #2)


    1. A01BDFBE10

      Connect an intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine and ECT / Data List / Accel Pos #1 and Accel Pos #2.

      Voltage

      Accelerator Pedal

      Operations

      ACCEL POS #1

      (AP #1)

      ACCEL POS #2

      (AP #2)
      Released 0.5 to 1.1 V 1.2 to 2.0 V
      Depressed 2.6 to 4.5 V 3.4 to 5.0 V

    OK

    REPLACE ACCELERATOR PEDAL ROD ASSEMBLY Click here

    NG

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


    1. A01BBRDE01

      Disconnect the B1 Accelerator Pedal Position (APP) sensor connector.

    2. Disconnect the B9 ECM connector.

    3. Measure the resistance.

      Resistance (Check for open)
      Tester Connections Specified Conditions
      VPA (B1-6) - VPA (B9-18) Below 1 Ω
      EPA (B1-5) - EPA (B9-20) Below 1 Ω
      VCPA (B1-4) - VCPA (B9-26) Below 1 Ω
      VPA2 (B1-3) - VPA2 (B9-19) Below 1 Ω
      EPA2 (B1-2) - EPA2 (B9-21) Below 1 Ω
      VCP2 (B1-1) - VCP2 (B9-27) Below 1 Ω
      Resistance (Check for short)
      Tester Connections Specified Conditions
      VPA (B1-6) or VPA (B9-18) - Body ground 10 kΩ or higher
      EPA (B1-5) or EPA (B9-20) - Body ground 10 kΩ or higher
      VCPA (B1-4) or VCPA (B9-26) - Body ground 10 kΩ or higher
      VPA2 (B1-3) or VPA2 (B9-19) - Body ground 10 kΩ or higher
      EPA2 (B1-2) or EPA2 (B9-21) - Body ground 10 kΩ or higher
      VCP2 (B1-1) or VCP2 (B9-27) - Body ground 10 kΩ or higher

    4. Reconnect the APP sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY


    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 the ON position and turn the tester ON.

    3. Clear DTCs Click here.

    4. Start the engine.

    5. Allow the engine to idle for 15 seconds.

    6. Select the following menu items: Powertrain / Engine and ECT / DTC.

    7. Read DTCs.

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

    B

    SYSTEM OK

    A

    REPLACE ECM