SFI SYSTEM, Diagnostic DTC:P2120,P2122,P2123,P2125,P2127,P2128 and 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

CAUTION / NOTICE / HINT

Tip:

  • These DTCs relate to the accelerator pedal position sensor.

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

DESCRIPTION

The accelerator pedal position sensor 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 driving conditions, such as at high speeds as well as very low speeds. 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 position (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 position sensor itself.

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

A255815E60

DTC No.

DTC Detection Condition

Trouble Area

P2120

VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).

  • Accelerator pedal position sensor

  • ECM

P2122

VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1 trip detection logic).

  • Accelerator pedal position sensor

  • Open in VCPA circuit

  • Open or ground short in VPA circuit

  • ECM

P2123

VPA is 4.8 V or higher for 2.0 seconds or more (1 trip detection logic).

  • Accelerator pedal position sensor

  • Open in EPA circuit

  • ECM

P2125

VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).

  • Accelerator pedal position sensor

  • ECM

P2127

VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1 trip detection logic).

  • Accelerator pedal position sensor

  • Open in VCP2 circuit

  • Open or ground short in VPA2 circuit

  • ECM

P2128

Conditions (a) and (b) continue for 2.0 seconds or more (1 trip detection logic):

(a) VPA2 is 4.8 V or higher

(b) VPA is between 0.4 V and 3.45 V.

  • Accelerator pedal position sensor

  • Open in EPA2 circuit

  • ECM

P2138

Condition (a) or (b) continues for 2.0 seconds or more (1 trip detection logic):

(a) The 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.

  • Short between VPA and VPA2 circuit

  • Accelerator pedal position sensor

  • ECM
Tip:

When any of these DTCs are output, check the accelerator pedal position sensor voltage by entering the following menus on the GTS: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

Trouble Area

Accel Sensor Out No. 1

When Accelerator Pedal Released

Accel Sensor Out No. 2

When Accelerator Pedal Released

Accel Sensor Out No. 1

When Accelerator Pedal Depressed

Accel Sensor Out No. 2

When Accelerator Pedal Depressed

VCP circuit open

0 to 0.2 V

0 to 0.2 V

0 to 0.2 V

0 to 0.2 V

Open or ground short in VPA circuit

0 to 0.2 V

1.2 to 2.0 V

0 to 0.2 V

3.4 to 4.75 V

Open or ground short in VPA2 circuit

0.5 to 1.1 V

0 to 0.2 V

2.6 to 4.5 V

0 to 0.2 V

EPA circuit open

4.5 to 4.98 V

4.5 to 4.98 V

4.5 to 4.98 V

4.5 to 4.98 V

Normal condition

0.5 to 1.1 V

1.2 to 2.0 V

2.6 to 4.5 V

3.4 to 4.75 V
Tip:

Accelerator pedal positions are expressed as voltages.

FAIL-SAFE

When DTC P2120, P2121, P2122, P2123, P2125, P2127, P2128 or P2138 is stored, the ECM enters fail-safe mode. If either of the 2 sensor circuits malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue being driven. If both of the circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles. Fail-safe mode continues until a pass condition is detected and the ignition switch is turned off.

WIRING DIAGRAM

A162855E26

CAUTION / NOTICE / HINT

Tip:

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)

    1. A208621E01

      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 Sensor Out No. 1 and Accel Sensor Out No. 2.

    4. Read the value 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 1.1 V

      1.2 to 2.0 V

      More than 0.02 V

      Depressed

      2.6 to 4.5 V

      3.4 to 4.75 V

    CHECK FOR INTERMITTENT PROBLEMS

    (Click here)

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

    1. Disconnect the accelerator pedal position sensor connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      A77-6 (VPA) - A76-47 (VPA)

      Always

      Below 1 Ω

      A77-5 (EPA) - A76-48 (EPA)

      Always

      Below 1 Ω

      A77-4 (VCPA) - A76-49 (VCPA)

      Always

      Below 1 Ω

      A77-3 (VPA2) - A76-50 (VPA2)

      Always

      Below 1 Ω

      A77-2 (EPA2) - A76-51 (EPA2)

      Always

      Below 1 Ω

      A77-1 (VCP2) - A76-52 (VCP2)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      A77-6 (VPA) or A76-47 (VPA) - Body ground

      Always

      10 kΩ or higher

      A77-5 (EPA) or A76-48 (EPA) - Body ground

      Always

      10 kΩ or higher

      A77-4 (VCPA) or A76-49 (VCPA) - Body ground

      Always

      10 kΩ or higher

      A77-3 (VPA2) or A76-50 (VPA2) - Body ground

      Always

      10 kΩ or higher

      A77-2 (EPA2) or A76-51 (EPA2) - Body ground

      Always

      10 kΩ or higher

      A77-1 (VCP2) or A76-52 (VCP2) - Body ground

      Always

      10 kΩ or higher

    4. Reconnect the accelerator pedal position sensor connector.

    5. Reconnect the ECM connector.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)

  3. CHECK ECM (VCPA AND VCP2 VOLTAGE)

    1. U122127E02

      Disconnect the accelerator pedal position sensor 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

      Switch Condition

      Specified Condition

      A77-4 (VCPA) - A77-5 (EPA)

      Ignition switch ON

      4.5 to 5.5 V

      A77-1 (VCP2) - A77-2 (EPA2)

      Ignition switch ON

      4.5 to 5.5 V
      Table 1. Text in Illustration

      *a

      Front view of wire harness connector

      (to Accelerator Pedal Position Sensor)

    4. Reconnect the accelerator pedal position sensor connector.

    REPLACE ECM

    (Click here)

  4. REPLACE ACCELERATOR PEDAL ASSEMBLY

    1. Replace the accelerator pedal assembly (Click here).

  5. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)

    1. Connect the GTS to the DLC3.

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

    3. Clear the DTCs (Click here).

    4. Start the engine.

    5. Allow the engine to idle for 15 seconds or more.

    6. Fully depress and release the accelerator pedal several times quickly.

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

    8. Read the DTCs.

      Table 2. Result

      Result

      Proceed to

      DTC P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 are output

      A

      DTC is not output

      B

    REPLACE ECM

    (Click here)

    END