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Home >> Lexus >> 2025 >> NX 350h >> Repair and Diagnosis >> External Pages >> Different car >> Section 29 (Engine Control System - Diagnostic Codes (P0520-P0627)) >> SFI System >> DTC P0627-12: Fuel Pump "A" Control Circuit Short to Battery [11/2021 - 03/2022] >> Procedure

DTC P0627-12: Fuel Pump "A" Control Circuit Short to Battery [11/2021 - 03/2022]: Procedure

WARNING: This page is about a different car, the 2025 Lexus NX 250, 2024 Lexus NX 250, 2023 Lexus NX 250, and 2022 Lexus NX 250. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT ECM (CHECK FOR SHORT) 
    1. Disconnect the fuel pump control ECU 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
      G106-2 (FPC) - Body ground Ignition switch ON Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  3

    Result: 

    OK 

    See step  2

  2. INSPECT ECM (FPC TERMINAL) 
    1. Disconnect the fuel pump control ECU connector.
    2. Operate the fuel pump control ECU using the Active Test function and measure the resistance according to the value(s) in the table below.

      Powertrain > Engine > Active Test 

      Tester Display
      Fuel Pump Single Phase Energization

      Standard Resistance

      Tester Connection GTS Operation Specified Condition
      G106-2 (FPC) - Body ground Before Active Test → During Active Test Before Active Test: Resistance is stable → During Active Test: Resistance fluctuates*

      HINT: 

      *: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the FPC terminal will be unstable during the Active Test. If the resistance is stable before the Active Test and fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUEL PUMP CONTROL ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

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

  3. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU - ECM) 
    1. Disconnect the fuel pump control ECU 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
      G106-2 (FPC) or A20-6 (FPC) - 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