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Home >> Lexus >> 2008 >> IS F >> Repair and Diagnosis >> Brakes >> Brakes Control Systems >> Brake Control / Dynamic Control Systems >> Vehicle Stability Control System >> DTC C1251/51 Open in Pump Motor Circuit >> Inspection Procedure
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Inspection Procedure

NOTE: When replacing the skid control ECU, perform zero point calibration and store system information (See CALIBRATION  ).

HINT:

When C0273/13, C0274/14 and/or C1361/91 is output together with C1251/51, inspect and repair the trouble areas indicated by C0273/13, C0274/14 and/or C1361/91 first (See DTC C0273/13 OPEN IN ABS MOTOR RELAY CIRCUIT; DTC C0274/14 SHORT TO B+ IN ABS MOTOR RELAY CIRCUIT; DTC C1361/91 SHORT CIRCUIT IN ABS MOTOR FAIL SAFE RELAY CIRCUIT  ).

  1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Select the Active Test mode on the Techstream (See DATA LIST / ACTIVE TEST  )

      ABS/VSC/TRAC 

      CONTROL RANGE REFERENCE

      Tester Display Test Part Control Range Diagnostic Note
      Motor Relay ABS motor relay Relay ON/OFF Operating sound of motor can be heard
    4. Check for the operating sound of the ABS motor relay when operating it using the Techstream.

      Result 

      RESULT REFERENCE

      Result Proceed to
      The operating sound is not heard A
      The operating sound is heard B

    B: Go to step  3

    A: Go to next step 

  2. INSPECT BRAKE ACTUATOR ASSEMBLY (GND2 TERMINAL) 
    1. Turn the engine switch off.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector
    3. Disconnect the brake actuator connector.
    4. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      STANDARD RESISTANCE

      Tester Connection Condition Specified Condition
      A13-1 (GND2) - Body ground Always Below 1 Ω
      5. Fig 1: Identifying Brake Actuator Assembly (GND2 Terminal)
      G05752632Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (GND2 CIRCUIT) 

    OK: Go to next step 

  3. RECONFIRM DTC 
    1. Reconnect the brake actuator connector.
    2. Clear the DTCs (See DTC CHECK / CLEAR  )
    3. Start the engine
    4. Drive the vehicle at a speed of 20 km/h (12 mph) or more for 30 seconds or more.
    5. Check if the same DTC is recorded (See DTC CHECK / CLEAR  ).

      Result 

      RESULT REFERENCE

      Result Proceed to
      DTC (C1251/51) is not output A
      DTC (C1251/51) is output B

      HINT

      • If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU with the engine switch on (IG) and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits
      • If the normal system code is output (no trouble codes are output), slightly jiggle the connectors, wire harness, and fuses of the skid control ECU and/or brake actuator assembly. Make sure that no DTCs are output.
      • If any DTCs are output while jiggling a connector or wire harness of the skid control ECU and/or brake actuator assembly, inspect and repair the connector or wire harness.
      • It is suspected that the DTCs were output due to a bad connection of the connector terminal.

    B: REPLACE SKID CONTROL ECU  (See REMOVAL  )

    A: CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)  (See DIAGNOSIS SYSTEM  )

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