ECD SYSTEM, Diagnostic DTC:P2120, P2122, P2123, P2125, P2127, P2128, P2138

DTC Code DTC Name
P2120 Throttle / Pedal Position Sensor / Switch "D" Circuit
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
P2125 Throttle / Pedal Position Sensor / Switch "E" Circuit
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


  • This is the repair procedure for the accelerator pedal position sensor.

  • This electrical throttle system does not use a throttle cable.

The accelerator pedal position sensor is mounted on the accelerator pedal and detects the opening angle of the accelerator pedal. It has 2 sensors to detect the accelerator position and a malfunction of the accelerator position sensor.

In the accelerator pedal position sensor, the voltage applied to pedal terminals VPA1 and VPA2 of the ECM changes between 0 V and 5 V in proportion to the opening angle of the accelerator pedal. The VPA1 is a signal to indicate the actual accelerator pedal opening angle which is used for the engine control, and the VPA2 is a signal to indicate the information about the opening angle which is used for detecting malfunctions. The ECM judges the current opening angle of the accelerator pedal using signals from terminals VPA1 and VPA2, and the ECM uses them as one of the conditions to control the injection volume and diesel throttle valve position.

A01KIG9E03
DTC No.

DTC Detection Condition

(All of following are 1 trip detection logic)

 Trouble Area
P2120

Condition (a) continues for 0.4 seconds or more:

(a) (VPA is 0.4 V or less) or (VPA is 4.8 V or more)

  • Accelerator pedal position sensor

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM
P2122 VPA is 0.4 V or less for 0.5 seconds or more when VPA2 output indicates accelerator pedal is opened

  • Accelerator pedal position sensor

  • Open in VCPA circuit

  • VPA circuit open or ground short

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM
P2123

Condition (a) continues for 2.0 seconds or more:

(a) VPA1 is 4.8 V or more

  • Accelerator pedal position sensor

  • Open in EPA circuit

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM
P2125

Condition (a) continues for 0.5 seconds or more:

(a) (VPA2 is 1.2 V or less) or (VPA2 is 4.8 V or more)

  • Accelerator pedal position sensor

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM
P2127 VPA2 is 1.2 V or less for 0.5 seconds or more when VPA output indicates accelerator pedal is opened

  • Accelerator pedal position sensor

  • Open in VCP2 circuit

  • VPA2 circuit open or ground short

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM
P2128

Conditions (a) and (b) continue for 2.0 seconds or more:

(a) VPA2 is 4.8 V or more

(b) VPA is 0.4 V or more and VPA1 is 3.45 V or less

  • Accelerator pedal position sensor

  • Open in EPA2 circuit

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM
P2138

Condition (a) or (b) continues for 2.0 seconds or more:

(a) Difference between VPA and VPA2 is 0.02 V or less

(b) VPA is 0.4 V or less and VPA2 is 1.2 V or less

  • VPA and VPA2 circuit are short circuited

  • Accelerator pedal position sensor

  • Accelerator pedal

  • Accelerator pedal rod (arm) deformed

  • ECM

Tech Tips

When DTC P2120, P2122, P2123, P2125, P2127, P2128 or P2138 is detected, check the output voltage of the accelerator pedal position sensor by selecting the following menu items on the intelligent tester: Powertrain / Engine / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.

- Accelerator pedal position expressed as voltage output
- Accelerator pedal released Accelerator pedal depressed
Trouble Area Accelerator Position No.1 Accelerator Position No. 2 Accelerator Position No. 1 Accelerator Position No. 2
VCP circuit open 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V
VPA circuit open or ground short 0 to 0.2 V 1.2 to 2.0 V 0 to 0.2 V 3.4 to 5.0 V
VPA2 circuit open or ground short 0.5 to 1.1 V 0 to 0.2 V 2.6 to 4.5 V 0 to 0.2 V
EP circuit open 4.5 to 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V

WIRING DIAGRAM

A01KFHZE02

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using an intelligent tester. Freeze frame data records the engine condition when a malfunction is 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.

Note

After replacing the ECM, the new ECM needs registration Click here and initialization Click here.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (ACCELERATOR POSITION NO. 1, ACCELERATOR POSITION NO. 2)


    1. A01KHAPE49
      Text in Illustration
      *a Depressed
      *b Released

      Connect the intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.

    4. Read the value displayed on the tester when the accelerator pedal is released and depressed.

      Standard voltage
      Accelerator Pedal Operations Accelerator Position No. 1 Accelerator Position No. 2
      Released → Depressed → Released 0.5 to 4.6 V 0.9 to 5.0 V
      Difference between Accelerator Position No. 1 and Accelerator Position No. 2 is greater than 0.02 V Difference between Accelerator Position No. 1 and Accelerator Position No. 2 is greater than 0.02 V

    OK

    CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTC IS OUTPUT AGAIN) Click here

    NG

  2. INSPECT ACCELERATOR PEDAL ASSEMBLY (ACCELERATOR PEDAL POSITION SENSOR)


    1. A01KEZVE01

      Disconnect the A8 Accelerator Pedal Position (APP) sensor connector.

    2. Measure the resistance between each terminal.

      Standard resistance
      Tester Connection Specified Condition
      3 - 6 1.5 to 6.0 kΩ at 20°C (68°F)
      1 - 4 1.5 to 6.0 kΩ at 20°C (68°F)

    3. Reconnect the APP sensor connector.


    NG

    REPLACE ACCELERATOR PEDAL ASSEMBLY

    OK

  3. INSPECT ECM (VCP1 AND VCP2 VOLTAGE)


    1. A01KGRQE01
      Text in Illustration
      *1 ECM Connector

      Disconnect the A8 APP sensor connector.

    2. Turn the ignition switch ON.

    3. Measure the voltage of the E7 ECM connector.

      Standard voltage
      Tester Connection Specified Condition
      E7-26 (VCPA) - E7-28 (EPA) 4.5 to 5.0 V
      E7-27 (VCP2) - E7-29 (EPA2) 4.5 to 5.0 V

    4. Reconnect the APP sensor connector.


    NG

    REPLACE ECM

    OK

  4. INSPECT ECM (VPA1 AND VPA2 VOLTAGE)


    1. A01KGRQE02
      Text in Illustration
      *1 ECM Connector

      Turn the ignition switch ON.

    2. Measure the voltage of the E7 ECM Connector.

      Standard voltage
      Tester Connection Accelerator Pedal Operation Specified Condition
      E7-22 (VPA) - E7-28 (EPA) Released 0.5 to 1.1 V
      Depressed 3.0 to 4.6 V
      E7-23 (VPA2) - E7-29 (EPA2) Released 0.9 to 2.3 V
      Depressed 3.4 to 5.0 V

    NG

    CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM) Click here

    OK

    REPLACE ECM

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


    1. A01KF94E03
      Text in Illustration
      *1 Accelerator Pedal Position Sensor Connector
      *2 ECM Connector
      *a Wire Harness Side
      *b Front View

      Disconnect the A8 APP sensor connector.

    2. Disconnect the E7 ECM connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connections Specified Conditions
      A8-4 (VCP1) - E7-26 (VCPA) Below 1 Ω
      A8-5 (VPA1) - E7-22 (VPA) Below 1 Ω
      A8-1 (EP1) - E7-28 (EPA) Below 1 Ω
      A8-6 (VCP2) - E7-27 (VCP2) Below 1 Ω
      A8-2 (VPA2) - E7-23 (VPA2) Below 1 Ω
      A8-3 (EP2) - E7-29 (EPA2) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connections Specified Conditions
      A8-4 (VCP1) or E7-26 (VCPA) - Body ground 10 kΩ or higher
      A8-5 (VPA1) or E7-22 (VPA) - Body ground 10 kΩ or higher
      A8-1 (EP1) or E7-28 (EPA) - Body ground 10 kΩ or higher
      A8-6 (VCP2) or E7-27 (VCP2) - Body ground 10 kΩ or higher
      A8-2 (VPA2) or- E7-23 (VPA2) - Body ground 10 kΩ or higher
      A8-3 (EP2) or E7-29 (EPA2) - 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

  6. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTC IS OUTPUT AGAIN)


    1. Clear the DTC Click here.

    2. Start the engine.

    3. Let the engine idle for 15 seconds or more.

    4. Select the following menu items: Powertrain / Engine / DTC.

    5. Read DTCs.

      Result
      Display (DTC Output) Proceed to
      P2120, P2122, P2123, P2125, P2127, P2128 or P2138 is output again A
      P2120, P2122, P2123, P2125, P2127, P2128 or P2138 is not output B

    B

    CHECK FOR INTERMITTENT PROBLEMS

    A

    REPLACE ECM