SFI SYSTEM, Diagnostic DTC:P2122, P2123, P2127, P2128, P2138

DTC Code DTC Name
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
P2138 Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation

DESCRIPTION

Tech Tips


  • These DTCs relate to the accelerator pedal sensor assembly.

  • This electronic throttle control system does not use a throttle cable.

The accelerator pedal sensor assembly is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type. It uses Hall-effect elements in order to yield accurate signals, even in extreme conditions. The voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0 V and 5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal operating angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the accelerator pedal sensor assembly itself.

The ECM monitors the actual accelerator pedal operating angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

Tech Tips

The accelerator pedal position output voltages of VPA and VPA2 are almost the same.

A004JTIE04
Text in Illustration
*a Accelerator pedal fully released *b Accelerator pedal fully depressed
- - - -
DTC No. DTC Detection Condition Trouble Area
P2122

VPA voltage is less than 0.303 V.

(1 trip detection logic)

  • Open or short in accelerator pedal sensor circuit

  • Accelerator pedal sensor assembly

  • ECM
P2123

VPA voltage is 4.737 V or more.

(1 trip detection logic)
P2127

VPA2 voltage is less than 0.303 V.

(1 trip detection logic)
P2128

VPA2 voltage is 4.737 V or more.

(1 trip detection logic)
P2138

Difference in the signals from VPA and VPA2 exceeds the threshold.

(1 trip detection logic)

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.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 stores the DTC.

CONFIRMATION DRIVING PATTERN


  1. A004I3BE07

  2. Connect the GTS to the DLC3.

  3. Turn the ignition switch to ON and turn the GTS on.

  4. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) Click here.

  5. Turn the ignition switch off and wait for at least 30 seconds.

  6. Turn the ignition switch to ON and turn the GTS on.

  7. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

  8. Depress the accelerator pedal fully and release the accelerator pedal.

  9. Drive the vehicle at 10 km/h (6.25 mph) or more for 1 minute or more [A].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

  10. Enter the following menus: Powertrain / Engine / Trouble Codes.

  11. Read pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  12. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

  13. Input the DTC: P2122, P2123, P2127, P2128 or P2138.

  14. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

  15. If the test result is INCOMPLETE or N/A and no DTC is output, perform a universal trip and check for permanent DTCs Click here.

    Tech Tips


    • If a permanent DTC is output, the system is malfunctioning.

    • If no permanent DTC is output, the system is normal.

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 fail-safe mode. In fail-safe 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 normal.

WIRING DIAGRAM

A004JGBE04
*a Shielded
*b Accelerator Pedal Position Sensor

CAUTION / NOTICE / HINT

Tech Tips


  • This DTC relates to the accelerator pedal position sensor.

  • Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

PROCEDURE


  1. READ VALUE USING GTS (ACCELERATOR PEDAL POSITION SENSOR)

    A004IZDE02
    Text in Illustration
    *a Depressed
    *b Released

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

    5. Read the values displayed on the GTS.

      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 0.8 V 0.5 to 0.8 V Less than 10%
      Depressed 2.4 to 3.5 V 2.4 to 3.5 V
      Result
      Result Proceed to
      NG A
      OK B

    B

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

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


    1. Disconnect the ECM connector.

    2. Disconnect the accelerator pedal sensor connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      A35-23 (VPA) - A23-6 (VPA1) Always Below 1 Ω
      A35-29 (EPA) - A23-5 (GND1) Always Below 1 Ω
      A35-21 (VCPA) - A23-4 (VC1) Always Below 1 Ω
      A35-31 (VPA2) - A23-3 (VPA2) Always Below 1 Ω
      A35-30 (EPA2) - A23-2 (GND2) Always Below 1 Ω
      A35-22 (VCP2) - A23-1 (VC2) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      A35-23 (VPA) or A23-6 (VPA1) - Body ground Always 10 kΩ or higher
      A35-29 (EPA) or A23-5 (GND1) - Body ground Always 10 kΩ or higher
      A35-21 (VCPA) or A23-4 (VC1) - Body ground Always 10 kΩ or higher
      A35-31 (VPA2) or A23-3 (VPA2) - Body ground Always 10 kΩ or higher
      A35-30 (EPA2) or A23-2 (GND2) - Body ground Always 10 kΩ or higher
      A35-22 (VCP2) or A23-1 (VC2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (VC VOLTAGE)


    1. A004H75E03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Accelerator Pedal Sensor)

      Disconnect the accelerator pedal sensor connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A23-4 (VC1) - A23-5 (GND1) Ignition Switch ON 4.5 to 5.5 V
      A23-1 (VC2) - A23-2 (GND2) Ignition Switch ON 4.5 to 5.5 V

    NG

    REPLACE ECM Click here

    OK

  4. REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY


    1. Replace the accelerator pedal sensor assembly Click here.


    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2122, P2123, P2127, P2128 OR P2138)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off and wait for at least 30 seconds.

    6. Turn the ignition switch to ON and turn the GTS on.

    7. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    8. Enter the following menus: Powertrain / Engine / Trouble Codes.

    9. Read DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC P2122, P2123, P2127, P2128, and/or P2138 is output B

    A

    END

    B

    REPLACE ECM Click here