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Home >> Lexus >> 2024 >> NX 250 FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 109 (Engine Control System - Diagnostic Codes (P26CA-U1150)) >> SFI System >> DTC P26CA-12: Engine Coolant Pump Circuit Short to Battery [03/2023 - ] >> Procedure

DTC P26CA-12: Engine Coolant Pump Circuit Short to Battery [03/2023 - ]: Procedure

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  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING)) 
    1. Disconnect the engine water pump assembly (water inlet housing) 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
      B31-2 (SWP) - 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 (INTERNAL CIRCUIT) 
    1. Disconnect the engine water pump assembly (water inlet housing) connector.
    2. Perform the Active Test using the GTS.

      Powertrain > Engine > Active Test 

      Tester Display
      Activate the Electric Water Pump
    3. Measure the resistance according to the value(s) in the table below.

      Standard

      Tester Connection Condition Specified Condition
      B31-2 (SWP) - Body ground 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 SWP terminal will be unstable during the Active Test. If the resistance 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 ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

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

  3. CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) - ECM) 
    1. Disconnect the engine water pump assembly (water inlet housing) 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
      B31-2 (SWP) or B92-50 (WPO) - 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