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Home >> Lexus >> 2019 >> ES 350 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 147 (Engine Control System (A25A-FXS) - Diagnostic Codes (19 Of 20)) >> SFI System >> DTC P26CA-12: Engine Coolant Pump Circuit Short to Battery [08/2020 - 08/2021] >> Procedure

DTC P26CA-12: Engine Coolant Pump Circuit Short to Battery [08/2020 - 08/2021]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus ES 300h, 2023 Lexus ES 300h, 2022 Lexus ES 300h, 2021 Lexus ES 300h, and 2020 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF WATER INLET HOUSING WITH WATER PUMP SUB-ASSEMBLY) 
    GTY805857Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Water Inlet Housing with Water Pump Sub-assembly)
    1. Disconnect the water inlet housing with water pump sub-assembly connector.
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      C66-2 (SWP) - Body ground Power switch on (IG) Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  3

    Result: 

    OK 

    See step  2

  2. INSPECT ECM (INTERNAL CIRCUIT) 
    GTY805857Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Water Inlet Housing with Water Pump Sub-assembly)
    1. Disconnect the water inlet housing with water pump sub-assembly connector.
    2. Turn the power switch on (IG).
    3. Measure the resistance according to the value(s) in the table below.

      Standard

      Tester Connection Condition Specified Condition
      C66-2 (SWP) - Body ground Power switch on (IG) Resistance fluctuates*

      HINT: 

      • *: When the connector of the water inlet housing with water pump sub-assembly is disconnected, the ECM will enter fail-safe mode. In this case, duty control of the transistors in the ECM will be performed and resistance fluctuates.
      • If the resistance fluctuates while the ECM is in fail-safe mode after the connector of the water inlet housing with water pump sub-assembly is disconnected, it can be determined that the transistor is operating.
      • If the transistor does not operate, the ECM may be malfunctioning.
      • If the resistance fluctuates after turning the power switch on (IG), it can be determined that the ECM is in fail-safe mode.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE WATER INLET HOUSING WITH WATER PUMP SUB-ASSEMBLY. Refer to  REMOVAL [06/2018 - ] 

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [08/2020 - 08/2021] 

  3. CHECK HARNESS AND CONNECTOR (WATER INLET HOUSING WITH WATER PUMP SUB-ASSEMBLY - ECM) 
    1. Disconnect the water inlet housing with water pump 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
      C66-2 (SWP) or C88-50 (WPO) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [08/2020 - 08/2021] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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