ECD SYSTEM(w/ Glow Plug Controller), Diagnostic DTC:P2122, P2123, P2127, P2128

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

DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal and detects the opening angle of the accelerator pedal. Since this sensor is electronically controlled with Hall-effect elements, accurate control and reliability can be obtained. The accelerator pedal position sensor has 2 sensors to detect the accelerator position and malfunctions of the accelerator position sensor.

In the accelerator pedal position sensor, the voltage applied to pedal terminals VPA and VPA2 of the ECM changes between 0.5 V and 5.5 V in proportion to the opening angle of the accelerator pedal. The VPA is a signal which indicates the actual accelerator pedal opening angle and is used for engine control, and the VPA2 is a signal which indicates the information about the opening angle and is used for detecting malfunctions. The ECM judges the current opening angle of the accelerator pedal using signals from terminals VPA and VPA2, and the ECM controls the injection volume based on these signals.

B0044TAE03
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input

VPA is less than 0.2 V for 0.5 seconds or more when accelerator pedal is depressed.

(1 trip detection logic)

  • Open or short in accelerator pedal sensor assembly circuit

  • Accelerator pedal position sensor

  • ECM

 Comes on DTC stored
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input

VPA is higher than 4.8 V for 0.5 seconds or more.

(1 trip detection logic)

  • Open or short in accelerator pedal sensor assembly circuit

  • Accelerator pedal position sensor

  • ECM

 Comes on DTC stored
P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input

VPA2 is less than 0.5 V for 0.5 seconds or more when accelerator pedal is depressed.

(1 trip detection logic)

  • Open or short in accelerator pedal sensor assembly circuit

  • Accelerator pedal position sensor

  • ECM

 Comes on DTC stored
P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input

VPA2 is higher than 4.8 V for 0.5 seconds or more.

(1 trip detection logic)

  • Open or short in accelerator pedal sensor assembly circuit

  • Accelerator pedal position sensor

  • ECM

 Comes on DTC stored
DTC Detection Drive Pattern
DTC No. DTC Detection Drive Pattern
P2122 Ignition switch ON
P2123
P2127
P2128
Related Data List
DTC No. Data List

P2122

P2123

P2127

P2128

  • Accel Position

  • Accel Sens. No. 1 Volt %

  • Accel Sens. No. 2 Volt %

Tech Tips


  • When DTC P2122, P2123, P2127 and/or P2128 are stored, as a fail-safe operation the ECM limits engine power, such as by estimating the accelerator pedal position as 0 %.

  • When DTC P2122, P2123, P2127 and/or P2128 are stored, check the accelerator pedal position sensor output by entering the following menus on the GTS: Powertrain / Engine and ECT / Data List / Accel Position.

Reference

Accel Position

(Fully Closed)

Accel Position

(Fully Open)

 Trouble Area
0% 0%

  • Open in VCPA or VCP2 circuit

  • Open or short in VPA or VPA2 circuit
Approximately 100% Approximately 100%

  • Open in EPA or EPA2 circuit

WIRING DIAGRAM

B0042GZE03
*a Accelerator Pedal Sensor Assembly

CAUTION / NOTICE / HINT

Note

When replacing the ECM, perform ECM Initialization and Registration.

Click here

Tech Tips


  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing a new ECM, perform all of the initialization and registration procedures for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • Read freeze frame data using the GTS. 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, and other data from the time the malfunction occurred.

PROCEDURE


  1. READ VALUE USING GTS (ACCEL SENS. NO.1 VOLT % AND ACCEL SENS. NO.2 VOLT %)

    B00426CC01
    *1 Accelerator Pedal
    *a Fully depressed
    *b Fully released

    1. Connect the GTS to the DLC3.

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

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sens. No.1 Volt % and Accel Sens. No.2 Volt %


      Powertrain > Engine and ECT > Data List
      Tester Display
      Accel Sens. No.1 Volt %
      Accel Sens. No.2 Volt %

    4. Read the value when fully depressing and fully releasing the accelerator pedal.

      Standard
      GTS Display Condition Specified Condition
      Accel Sens. No.1 Volt % Fully depressed 52 to 90%
      Fully released 10 to 22%
      Accel Sens. No.2 Volt % Fully depressed 68 to 99%
      Fully released 24 to 40%
      Result
      Proceed to
      OK
      NG

    OK

    GO TO STEP 8 Click here

    NG

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


    1. Disconnect the accelerator pedal sensor assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A3-1 (VCP2) - A169-28 (VCP2) Always Below 1 Ω
      A3-2 (EPA2) - A169-23 (EPA2) Always Below 1 Ω
      A3-3 (VPA2) - A169-43 (VPA2) Always Below 1 Ω
      A3-4 (VCPA) - A169-27 (VCPA) Always Below 1 Ω
      A3-5 (EPA) - A169-22 (EPA) Always Below 1 Ω
      A3-6 (VPA) - A169-42 (VPA) Always Below 1 Ω
      A3-1 (VCP2) or A169-28 (VCP2) - Body ground and other terminals Always 10 kΩ or higher
      A3-2 (EPA2) or A169-23 (EPA2) - Body ground and other terminals Always 10 kΩ or higher
      A3-3 (VPA2) or A169-43 (VPA2) - Body ground and other terminals Always 10 kΩ or higher
      A3-4 (VCPA) or A169-27 (VCPA) - Body ground and other terminals Always 10 kΩ or higher
      A3-5 (EPA) or A169-22 (EPA) - Body ground and other terminals Always 10 kΩ or higher
      A3-6 (VPA) or A169-42 (VPA) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  3. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ACCELERATOR PEDAL SENSOR ASSEMBLY)

    B0044UHC01
    *a

    Front view of wire harness connector

    (to Accelerator Pedal Sensor Assembly)

    1. Disconnect the accelerator pedal sensor assembly connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A3-4 (VCPA) - A3-5 (EPA) Ignition switch ON 4.5 to 5.5 V
      A3-1 (VCP2) - A3-2 (EPA2) Ignition switch ON 4.5 to 5.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ECM Click here

    OK

  4. REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY


    1. Replace the accelerator pedal sensor assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the GTS to the DLC3.

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

    3. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs

    4. Turn the ignition switch off and wait for 30 seconds or more.

    5. Turn the ignition switch to ON.

    6. Fully close the accelerator pedal for 3 seconds, and then hold it partway open for 3 seconds, then fully open it for 3 seconds.

    7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    8. Read the DTCs.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Result Proceed to
      DTC P2122, P2123, P2127 and/or P2128 is output A
      DTC is not output B

    B

    END

    A

  6. REPLACE ECM


    1. Replace the ECM.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here

  7. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result
    Proceed to
    NEXT

    NEXT

  8. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

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

    3. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs

    4. Turn the ignition switch off and wait for 30 seconds or more.

    5. Turn the ignition switch to ON.

    6. Fully close the accelerator pedal for 3 seconds, and then hold it partway open for 3 seconds, then fully open it for 3 seconds.

    7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    8. Confirm that the DTC is not output again.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Proceed to
      NEXT

    NEXT

    END