SFI SYSTEM, Diagnostic DTC:P0121,P0122,P0123,P2122 and P2123

DTC Code DTC Name
P0121 Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance
P0122 Throttle / Pedal Position Sensor / Switch "A" Circuit Low
P0123 Throttle / Pedal Position Sensor / Switch "A" Circuit High
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High

DESCRIPTION

The throttle position sensor is mounted on the throttle body with motor assembly, and detects the opening angle of the throttle valve.

The throttle body with motor assembly sensor has 2 sensor circuits which each transmits a signal, VTA and VTA2. VTA is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA.

A331359E01

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0121

Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance

Difference between output voltages of VTA and VTA2 is higher than threshold.

  • Throttle body with motor assembly

  • Wire harness or connector

  • ECM

Comes on

DTC stored

P0122

Throttle / Pedal Position Sensor / Switch "A" Circuit Low

Short to ground in throttle position sensor (VTA) circuit.

  • Throttle body with motor assembly

  • Wire harness or connector

  • ECM

Comes on

DTC stored

P0123

Throttle / Pedal Position Sensor / Switch "A" Circuit High

Open or short to +B in throttle position sensor (VTA) circuit.

  • Throttle body with motor assembly

  • Wire harness or connector

  • ECM

Comes on

DTC stored

P2122

Throttle / Pedal Position Sensor / Switch "D" Circuit Low

Short to ground in throttle position sensor (VTA2) circuit.

  • Throttle body with motor assembly

  • Wire harness or connector

  • ECM

Comes on

DTC stored

P2123

Throttle / Pedal Position Sensor / Switch "D" Circuit High

Open or short to +B in throttle position sensor (VTA2) circuit.

  • Throttle body with motor assembly

  • Wire harness or connector

  • ECM

Comes on

DTC stored

MONITOR DESCRIPTION

These DTCs are stored when a malfunction is detected in the throttle position sensor circuit. If there is an open or short in the throttle position sensor circuit or the difference between the output voltage of VTA and VTA2 is outside of the threshold, the ECM will illuminate the MIL and store a DTC.

WIRING DIAGRAM

A331071E01

CAUTION / NOTICE / HINT

Note:

If the throttle body with motor assembly is repaired or replaced, perform BPM Learning Reset.

Click here

PROCEDURE

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0121, P0122, P0123, P2122 AND/OR P2123)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

    5. Check for DTCs.

      Powertrain > Engine > Trouble Codes

      Result

      Result

      Proceed to

      DTC P0121, P0122, P0123, P2122 and/or P2123 is output

      A

      DTC P0121, P0122, P0123, P2122 and/or P2123 and other DTCs are output

      B
      Tip:

      If DTC P0121, P0122, P0123, P2122 and/or P2123 and P2670, P2137, P0222, P0223, P0227, P0228 or P0658 are output simultaneously, troubleshoot for DTC P2670, P2137, P0222, P0223, P0227, P0228 or P0658 first.

    B

    GO TO DTC CHART

    Click here

    A

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

    1. Disconnect the throttle body with motor 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

      B54-4 (VCTA) - B55-34 (VCTA)

      Always

      Below 1 Ω

      B54-5 (VTA) - B55-10 (VTA)

      Always

      Below 1 Ω

      B54-6 (VTA2) - B55-11 (VTA2)

      Always

      Below 1 Ω

      B54-3 (ETA) - B55-22 (ETA)

      Always

      Below 1 Ω

      B54-4 (VCTA) or B55-34 (VCTA) - Body ground and other terminals

      Always

      10 kΩ or higher

      B54-5 (VTA) or B55-10 (VTA) - Body ground and other terminals

      Always

      10 kΩ or higher

      B54-6 (VTA2) or B55-11 (VTA2) - Body ground and other terminals

      Always

      10 kΩ or higher

      B54-3 (ETA) or B55-22 (ETA) - Body ground and other terminals

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. READ VALUE USING GTS (THROTTLE SENSOR VOLTAGE)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Sensor Voltage Position No.1 BPM (Gross Value of Angle) and Sensor Voltage Position No.2 BPM (Gross Value of Angle).

      Powertrain > Engine > Data List

      Tester Display

      Sensor Voltage Position No.1 BPM (Gross Value of Angle)

      Sensor Voltage Position No.2 BPM (Gross Value of Angle)

    5. Start the engine and read the values.

      Standard

      Data List

      Condition

      Standard Value

      Total of Sensor Voltage Position No.1 BPM (Gross Value of Angle) and Sensor Voltage Position No.2 BPM (Gross Value of Angle)

      Accelerator pedal full closed

      Total voltage: 4750 to 5250 mV

      Accelerator pedal half open

      Accelerator pedal fully open
      Tip:

      Example (Normal Condition):

      Sensor Voltage Position No.1 BPM (Gross Value of Angle): 940 mV

      Sensor Voltage Position No.2 BPM (Gross Value of Angle): 4060 mV

      Total Voltage: 940 + 4060 = 5000 mV

    Result

    Proceed to

    OK

    NG
    OK

    CHECK FOR INTERMITTENT PROBLEMS

    Click here

    NG

  4. CHECK TERMINAL VOLTAGE (POWER SOURCE OF THROTTLE POSITION SENSOR)

    A340584C01

    *a

    Front view of wire harness connector

    (to Throttle Body with Motor Assembly)

    1. Disconnect the throttle body with motor 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

      B54-4 (VCTA) - B54-3 (ETA)

      Ignition switch ON

      4.5 to 5.5 V

    Result

    Proceed to

    OK

    NG
    NG

    GO TO DTC P2685

    Click here

    OK

  5. REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY

    1. Replace the throttle body with motor assembly.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  6. CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs

    5. Turn the ignition switch off and wait for a few minutes.

    6. Perform the drive test.

    7. Turn the GTS on.

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

    9. Check for DTCs.

      Powertrain > Engine > Trouble Codes

    Result

    Result

    Proceed to

    DTC P0121, P0122, P0123, P2122 and/or P2123 are output

    A

    DTCs are not output

    B
    A

    REPLACE ECM

    Click here

    B

    END