SFI 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

CAUTION / NOTICE / HINT

Tech Tips

These DTCs relate to the accelerator pedal position sensor.

DESCRIPTION

Tech Tips

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

The accelerator pedal position sensor is integrated with the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type, and 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 opening 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 position sensor itself.

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

A017G73E06
DTC No. DTC Detection Condition Trouble Area
P2120 VPA fluctuates rapidly beyond 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 accelerator pedal is fully released (1 trip detection logic)

  • Accelerator pedal position sensor

  • Open in VCP1 circuit

  • Open or ground short in VPA circuit

  • ECM
P2123 VPA is 4.8 V or more for 2.0 seconds or more (1 trip detection logic)

  • Accelerator pedal position sensor

  • Open in EPA circuit

  • ECM
P2125 VPA2 fluctuates rapidly beyond 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 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 more

(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) 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 circuits

  • Accelerator pedal position sensor

  • ECM

Tech Tips

When any of these DTCs are set, check the accelerator pedal position sensor voltage by selecting the following menu items on the intelligent tester: Powertrain / Engine and ECT / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.

Trouble Area Accelerator Position No. 1 When accelerator pedal Released Accelerator Position No. 2 When accelerator pedal Released Accelerator Position No. 1 When accelerator pedal Depressed Accelerator Position 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 5.0 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 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V
Normal condition 0.5 to 1.1 V 1.2 to 2.0 V 2.6 to 4.5 V 3.4 to 5.0 V

Tech Tips

Accelerator pedal positions are expressed as voltages.

FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are set, 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 driving. 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

A017C9NE08

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the 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 (ACCELERATOR POSITION NO. 1 AND ACCELERATOR POSITION NO. 2)


    1. A017G5YE14

      Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG) and turn the tester on.

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

    4. Read the values displayed on the tester.

      Standard voltage
      Accelerator Pedal Operation Accelerator Position No. 1 Accelerator Position No. 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

    NG

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

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

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


    1. A017C14E04

      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
      A19-6 (VPA) - D31-18 (VPA) Always Below 1 Ω
      A19-5 (EPA) - D31-20 (EPA) Always Below 1 Ω
      A19-4 (VCPA) - D31-26 (VCPA) Always Below 1 Ω
      A19-3 (VPA2) - D31-19 (VPA2) Always Below 1 Ω
      A19-2 (EPA2) - D31-21 (EPA2) Always Below 1 Ω
      A19-1 (VCP2) - D31-27 (VCP2) Always Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      A19-6 (VPA) or D31-18 (VPA) - Body ground Always 10 kΩ or higher
      A19-5 (EPA) or D31-20 (EPA) - Body ground Always 10 kΩ or higher
      A19-4 (VCPA) or D31-26 (VCPA) - Body ground Always 10 kΩ or higher
      A19-3 (VPA2) or D31-19 (VPA2) - Body ground Always 10 kΩ or higher
      A19-2 (EPA2) or D31-21 (EPA2) - Body ground Always 10 kΩ or higher
      A19-1 (VCP2) or D31-27 (VCP2) - Body ground Always 10 kΩ or higher

    4. Reconnect the accelerator pedal position sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (VCPA AND VCP2 VOLTAGE)


    1. A017FW5E09

      Disconnect the accelerator pedal position sensor connector.

    2. Turn the ignition switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      D31-26 (VCPA) - D31-20 (EPA) Ignition switch on (IG) 4.5 to 5.0 V
      D31-27 (VCP2) - D31-21 (EPA2) Ignition switch on (IG) 4.5 to 5.0 V

    4. Reconnect the accelerator pedal position sensor connector.


    NG

    REPLACE ECM Click here

    OK

  4. REPLACE ACCELERATOR PEDAL


    1. Replace the accelerator pedal Click here.


    NEXT

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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG) and turn the tester on.

    3. Clear the DTCs Click here.

    4. Start the engine.

    5. Allow the engine to idle for 15 seconds.

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

    7. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P2120, P2122, P2123, P2125, P2127, P2128 and/or P2138 A
      No output B

    B

    SYSTEM OK

    A

    REPLACE ECM Click here