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Home >> Lexus >> 2024 >> NX 250 FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 125 (Engine Control System - Diagnostic Codes (P0190-P02EE)) >> SFI System >> DTC P0234-00: Turbocharger/Supercharger "A" Overboost Condition [11/2021 - ] >> Procedure

DTC P0234-00: Turbocharger/Supercharger "A" Overboost Condition [11/2021 - ]: Procedure

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  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0234-00) 
    1. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTC P0234-00 is output A
      DTC P0234-00 and other DTCs are output B

      HINT: 

      If any DTCs other than P0234-00 are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - 03/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2023 - 03/2024]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2024 - ] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS (ATMOSPHERIC PRESSURE) 
    1. Check the value of Data List item.

      Powertrain > Engine > Data List 

      Tester Display
      Atmospheric Pressure
    2. Using the following table, determine the normal atmospheric pressure for the current altitude and temperature.
      GTY518158Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT: 

      • Standard atmospheric pressure is approximately 101 kPa (abs) (14.65 psi (abs)).
      • For every 100 m (328 ft.) increase in altitude, atmospheric pressure drops by approximately 1 kPa (0.15 psi). This varies depending on the weather.
    3. Compare the value of Atmospheric Pressure with the normal atmospheric pressure in the table.

      Result

      Result Proceed to
      Other than below A
      Difference between value of Atmospheric Pressure and normal atmospheric pressure is 10 kPa (1.45 psi) or higher B

    Result: 

    B 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    A 

    See step  3

  3. READ VALUE USING GTS (INTAKE AIR TEMPERATURE) 
    1. According to the display on the GTS, read the Data List.

      Powertrain > Engine > Data List 

      Tester Display
      Intake Air Temperature

      Result

      Result Proceed to
      Difference between value of Intake Air Temperature and actual ambient air temperature is 10°C (18°F) or higher A
      Other than above B

    Result: 

    B 

    See step  16

    Result: 

    A 

    See step  4

  4. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY 
    1. Inspect the mass air flow meter sub-assembly, referring to On-vehicle Inspection for Mass Air Flow Meter.

      Refer to ON-VEHICLE INSPECTION [11/2021 - ]

    2. Inspect the mass air flow meter sub-assembly, referring to Inspection for Mass Air Flow Meter.

      Refer to INSPECTION [11/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  5

  5. INSPECT NO. 2 TURBO PRESSURE SENSOR 
    1. Inspect the No. 2 turbo pressure sensor.

      Refer to PROCEDURE - Step 1

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  6

  6. INSPECT TURBOCHARGER SUB-ASSEMBLY (WASTE GATE VALVE) 
    1. Inspect the waste gate valve.

      Refer to INSPECTION [11/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE TURBOCHARGER SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  7

  7. INSPECT VACUUM REGULATING VALVE ASSEMBLY 
    1. Inspect the vacuum regulating valve assembly.

      Refer to INSPECTION [11/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE VACUUM REGULATING VALVE ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  8

  8. INSPECT TURBOCHARGER SUB-ASSEMBLY (WASTE GATE VALVE ACTUATOR) 
    1. Inspect the waste gate valve actuator.

      Refer to ON-VEHICLE INSPECTION [11/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE TURBOCHARGER SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (VACUUM REGULATING VALVE ASSEMBLY - ECM) 
    1. Disconnect the vacuum regulating valve 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
      B70-1 (+) - B49-20 (WGV+) Always Below 1 Ω
      B70-2 (-) - B49-21 (WGV-) Always Below 1 Ω
      B70-1 (+) or B49-20 (WGV+) - Body ground and other terminals Always 10 kΩ or higher
      B70-2 (-) or B49-21 (WGV-) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK WHETHER DTC OUTPUT RECURS (DTC P0234-00) 
    1. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    2. Turn the ignition switch off and wait for at least 30 seconds.
    3. Start the engine and warm it up.
    4. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    5. Check the DTC judgment result.

      Powertrain > Engine > Utility 

      Tester Display
      All Readiness
    6. Input the DTC: P0234-00.

      Result

      Result Proceed to
      NORMAL
      (DTCs are not output)      		 A
      ABNORMAL
      (DTC P0234-00 is output)      		 B

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

  11. CHECK TERMINAL VOLTAGE (POWER SOURCE OF NO. 2 TURBO PRESSURE SENSOR) 
    1. Disconnect the No. 2 turbo pressure 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 Condition Specified Condition
      B72-3 (VC) - B72-2 (E2) Ignition switch ON 4.5 to 5.5 V
      B72-1 (PTA) - B72-2 (E2) Ignition switch ON 3.0 to 5.0 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 TURBO PRESSURE SENSOR. Refer to  PROCEDURE - Step 1 

    Result: 

    NG 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (NO. 2 TURBO PRESSURE SENSOR - ECM) 
    1. Disconnect the No. 2 turbo pressure sensor 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
      B72-3 (VC) - B49-102 (VPTA) Always Below 1 Ω
      B72-2 (E2) - B49-125 (EPTA) Always Below 1 Ω
      B72-1 (PTA) - B49-126 (PTA) Always Below 1 Ω
      B72-3 (VC) or B49-102 (VPTA) - Body ground and other terminals Always 10 kΩ or higher
      B72-1 (PTA) or B49-126 (PTA) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. CHECK TERMINAL VOLTAGE (POWER SOURCE OF MASS AIR FLOW METER SUB-ASSEMBLY) 
    1. Disconnect the mass air flow meter sub-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
      B20-3 (VCC) - B20-2 (E2G) Ignition switch ON 4.8 to 5.2 V
      B20-1 (FG) - B20-2 (E2G) Ignition switch ON 4.8 to 5.2 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  15

    Result: 

    OK 

    See step  14

  14. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY 
    1. Inspect the mass air flow meter sub-assembly.

      Refer to ON-VEHICLE INSPECTION [11/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

  15. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 
    1. Disconnect the mass air flow meter sub-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
      B20-3 (VCC) - B49-73 (VCVG) Always Below 1 Ω
      B20-1 (FG) - B49-75 (VG) Always Below 1 Ω
      B20-2 (E2G) - B49-74 (E2G) Always Below 1 Ω
      B20-3 (VCC) or B49-73 (VCVG) - Body ground and other terminals Always 10 kΩ or higher
      B20-1 (FG) or B49-75 (VG) - Body ground and other terminals Always 10 kΩ or higher
      B20-2 (E2G) or B49-74 (E2G) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  16. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY (INTAKE AIR TEMPERATURE SENSOR) 
    1. Inspect the mass air flow meter sub-assembly (intake air temperature sensor).

      Refer to INSPECTION [11/2021 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

      Refer to INITIALIZATION [11/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  17

  17. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 
    1. Disconnect the mass air flow meter sub-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
      B20-4 (THA) - B49-76 (THA) Always Below 1 Ω
      B20-2 (E2G) - B49-74 (E2G) Always Below 1 Ω
      B20-4 (THA) or B49-76 (THA) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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