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

DESCRIPTION

Tech Tips

  • This Electronic Throttle Control System (ETCS) does not use a throttle cable.

  • These DTCs relate to the accelerator pedal position sensor.

The accelerator pedal position sensor is built into the accelerator pedal sensor assembly and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type sensor 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 0.5 V and 4.75 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.

A011SLOE03
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 sensor assembly

  • ECM
P2122 VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is depressed (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • 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 sensor assembly

  • 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 sensor assembly

  • ECM
P2127 VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is depressed (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • Open in VCP2 circuit

  • Open or ground short in VPA2 circuit

  • ECM
P2128

Both of the following conditions 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 sensor assembly

  • Open in EPA2 circuit

  • ECM
P2138

Either of the following conditions 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 circuits

  • Accelerator pedal sensor assembly

  • ECM

Tech Tips

When any of these DTCs are output, check the accelerator pedal position sensor voltage using the Techstream. Enter the following menus: Powertrain / Engine / Data List / Gas Throttle / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

Trouble Area Accelerator Pedal Fully Released Accelerator Pedal Fully Depressed
Accel Sensor Out No. 1 Accel Sensor Out No. 2 Accel Sensor Out No. 1 Accel Sensor Out No. 2
Open in VCP circuit 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
Open in EPA circuit 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

Tech Tips

Accelerator pedal positions are expressed as voltages.

MONITOR DESCRIPTION

When either output voltage of VPA or VPA2 deviates from the standard range, or the difference between the output voltages of the 2 sensor circuits is more than the threshold, the ECM determines that there is a malfunction in the accelerator pedal position sensor. The ECM then illuminates the MIL and stores a DTC.

Example:

When the output voltage of VPA is less than 0.4 V for more than 0.5 seconds when the accelerator pedal is fully depressed, DTC P2122 is stored.

MONITOR STRATEGY

Related DTCs

P2120: Accelerator pedal position sensor 1 range check (chattering)

P2122: Accelerator pedal position sensor 1 range check (low voltage)

P2123: Accelerator pedal position sensor 1 range check (high voltage)

P2125: Accelerator pedal position sensor 2 range check (chattering)

P2127: Accelerator pedal position sensor 2 range check (low voltage)

P2128: Accelerator pedal position sensor 2 range check (high voltage)

P2138: Accelerator pedal position sensor range check (correlation)
Required Sensors/Components (Main) Accelerator pedal sensor assembly
Required Sensors/Components (Related) -
Frequency of Operation Continuous
Duration

0.5 seconds: P2120, P2122, P2125 and P2127

2.0 seconds: P2123, P2128 and P2138
MIL Operation Immediate
Sequence of Operation None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored None
Either of the following conditions is met A or B
A. Time after engine switch off to on (IG) 0.012 seconds or more
B. Electronic throttle actuator power On

TYPICAL MALFUNCTION THRESHOLDS

P2120
Either of the following conditions is met 1 or 2
1. Both of the following conditions are met -
VPA voltage 0.4 V or less
VPA2 voltage - Learned VPA2 accelerator off position voltage 0.04 V or higher
2. VPA voltage 4.8 V or higher
P2122
Both of the following conditions are met -
VPA voltage 0.4 V or less
VPA2 voltage - Learned VPA2 accelerator off position voltage 0.04 V or higher
P2123
VPA voltage 4.8 V or higher
P2125
Either of the following conditions is met 1 or 2
1. Both of the following conditions are met -
VPA2 voltage 1.2 V or less
VPA voltage - Learned VPA accelerator off position voltage 0.04 V or higher
2. VPA2 voltage when VPA voltage 0.4 to 3.45 V 4.8 V or higher
P2127
Both of the following conditions are met -
VPA2 voltage 1.2 V or less
VPA voltage - Learned VPA accelerator off position voltage 0.04 V or higher
P2128
VPA2 voltage when VPA voltage 0.4 to 3.45 V 4.8 V or higher
P2138
Either of the following conditions is met A or B
A. Difference between VPA and VPA 2 voltages 0.02 V or less
B. Both of the following conditions are met -
VPA voltage 0.4 V or less
VPA2 voltage 1.2 V or less

COMPONENT OPERATING RANGE

VPA voltage Higher than 0.4 V, and less than 4.8 V
VPA2 voltage Higher than 1.2 V, and less than 4.8 V
Difference between VPA and VPA2 voltages Higher than 0.02 V

CONFIRMATION DRIVING PATTERN

A011QMSE04

  1. Connect the Techstream to the DLC3.

  2. Turn the engine switch on (IG) and turn the Techstream on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the Techstream on [A].

  6. Fully depress and release the accelerator pedal [B].

  7. Check that 5 seconds or more have elapsed since the engine switch is turned on (IG).

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

  9. Read the 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.

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

  11. Input the DTC: P2120, P2122, P2123, P2125, P2127, P2128 or P2138.

  12. Check the DTC judgment result.

    Techstream 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.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] and [C] again.

  13. If no pending 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

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 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 engine switch is turned off.

WIRING DIAGRAM

A011SDTE02

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the Techstream. 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 TECHSTREAM (ACCEL SENSOR OUT)

    1. Connect the Techstream to the DLC3.

      A011V1IE02

    2. Turn the engine switch on (IG).

    3. Turn the Techstream on.

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

    5. Read the value displayed on the Techstream.

      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
      Fully Released 0.5 to 1.1 V 1.2 to 2.0 V More than 0.02 V
      Fully Depressed 2.6 to 4.5 V 3.4 to 4.75 V
      Text in Illustration
      *a Fully Depressed
      *b Fully Released
    NG

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

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  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
      A36-6 (VPA) - A25-54 (VPA) Always Below 1 Ω
      A36-5 (EPA) - A25-55 (EPA) Always Below 1 Ω
      A36-4 (VCPA) - A25-56 (VCPA) Always Below 1 Ω
      A36-3 (VPA2) - A25-57 (VPA2) Always Below 1 Ω
      A36-2 (EPA2) - A25-58 (EPA2) Always Below 1 Ω
      A36-1 (VCP2) - A25-59 (VCP2) Always Below 1 Ω
      A36-6 (VPA) or A25-54 (VPA) - Body ground Always 10 kΩ or higher
      A36-4 (VCPA) or A25-56 (VCPA) - Body ground Always 10 kΩ or higher
      A36-3 (VPA2) or A25-57 (VPA2) - Body ground Always 10 kΩ or higher
      A36-1 (VCP2) or A25-59 (VCP2) - Body ground Always 10 kΩ or higher
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    1. Disconnect the accelerator pedal sensor assembly connector.

      A011U3YE16

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A36-4 (VCPA) - A36-5 (EPA) Engine switch on (IG) 4.5 to 5.5 V
      A36-1 (VCP2) - A36-2 (EPA2) Engine switch on (IG) 4.5 to 5.5 V
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Accelerator Pedal Sensor Assembly)
    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 (ACCELERATOR PEDAL SENSOR DTCS)

    1. Connect the Techstream to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the Techstream on.

    4. Clear the DTCs Click here.

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

    6. Turn the engine switch on (IG) and turn the Techstream 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 the DTCs.

      Result
      Result Proceed to
      DTC P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 are output A
      DTC is not output B
    B

    END

    A

    REPLACE ECM Click here