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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 104 (Engine Control System - Diagnostic Codes (P2270-P26CE)) >> SFI System >> DTC P2681-11: Engine Coolant Bypass Valve Circuit Short to Ground; DTC P2681-15: Engine Coolant Bypass Valve Circuit Short to Battery or Open [08/2023 - ] >> Procedure

DTC P2681-11: Engine Coolant Bypass Valve Circuit Short to Ground; DTC P2681-15: Engine Coolant Bypass Valve Circuit Short to Battery or Open [08/2023 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus RX 450h+, 2025 Lexus RX 350h, 2024 Lexus RX 450h+, 2024 Lexus RX 350h, and 2023 Lexus RX 350h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF FLOW SHUTTING VALVE) 

    Pre-procedure1

    • Disconnect the flow shutting valve (water by-pass hose assembly) connector.
    • Turn the ignition switch to ON.
    • Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      B78-2 (+FSV) - Body ground Ignition switch ON 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - FLOW SHUTTING VALVE) 

    Result: 

    OK 

    See step  2

  2. INSPECT FLOW SHUTTING VALVE (WATER BY-PASS HOSE ASSEMBLY) 

    HINT: 

    Refer to INSPECTION [10/2022 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE FLOW SHUTTING VALVE (WATER BY-PASS HOSE ASSEMBLY). Refer to  REMOVAL [08/2023 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (FLOW SHUTTING VALVE - ECM) 

    Pre-procedure1

    • Disconnect the flow shutting valve (water by-pass hose assembly) connector.
    • Disconnect the ECM connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      B78-1 (-FSV) - B28-42 (WSV1) Always Below 1 Ω Ω
      B78-1 (-FSV) or B28-42 (WSV1) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR