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Home >> Lexus >> 2023 >> NX 250 AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 6 (Electronically Controlled Brake System - Diagnostic Codes (5 Of 6)) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HEV Model) >> DTC C1427-71: ABS Pump Motor Actuator Stuck [11/2021 - ] >> Procedure

DTC C1427-71: ABS Pump Motor Actuator Stuck [11/2021 - ]: Procedure

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  1. PERFORM ACTIVE TEST USING GTS (MOTOR RELAY) 
    1. Check the operating sound of the pump motor when operating it using the GTS.

      Chassis > Brake/EPB > Active Test 

      Tester Display Measurement Item Control Range Restrict Condition Diagnostic Note
      Motor Relay ABS motor relay OFF / ON Vehicle condition: Vehicle stopped
      HINT: 
      To protect this Actuator and Solenoid, this test will only last 5 seconds.      		 Operating sound of motor can be heard

      Chassis > Brake/EPB > Active Test 

      Tester Display
      Motor Relay

      Result

      Result Proceed to
      Operating sound is heard. A
      Operating sound is not heard. B

    Result: 

    B 

    See step  4

    Result: 

    A 

    See step  2

  2. CLEAR DTC 
    1. Clear the DTCs.

      Chassis > Brake/EPB > Clear DTCs 

    2. Turn the ignition switch off.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  3

  3. RECONFIRM DTC 
    1. Based on the Freeze Frame Data and interview with the customer, attempt to reproduce the conditions when the malfunction occurred.
    2. Check if the same DTC is output.

      Chassis > Brake/EPB > Trouble Codes 

      HINT: 

      • If a speed signal of 20 km/h (12 mph) or more is input to the No. 2 skid control ECU (brake actuator assembly) with the ignition switch turned to ON and the stop light switch assembly off, the ECU performs self-diagnosis of the pump motor circuit.
      • If the normal system code is output (no DTCs are output), slightly jiggle the connectors, wire harness, and fuses of the No. 2 skid control ECU (brake actuator assembly).
      • If any DTCs are output while jiggling a connector or wire harness of the No. 2 skid control ECU (brake actuator assembly), inspect and repair the connector or wire harness.
      • If no DTCs were output when reconfirming DTCs, checking for intermittent problems is necessary because it is suspected that the original DTCs were stored due to the poor connection of a connector terminal.

      Result

      Result Proceed to
      DTC C1427-71 is not output. A
      DTC C1427-71 is output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ] 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

  4. CHECK HARNESS AND CONNECTOR (GND2 TERMINAL) 
    1. Turn the ignition switch off.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      OK

      The connector is securely connected.

    3. Disconnect the A38 No. 2 skid control ECU (brake actuator assembly) connector.
    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A38-30 (GND2) - Body ground 1 minute or more after disconnecting the cable from the negative (-) auxiliary battery terminal Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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