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Home › Lexus › 2008 › LS 600hL › Repair and Diagnosis › Suspension › Suspension Control Systems › Suspension Control › Air Suspension System › DTC C1784 Steering Angle Sensor Communication Error › Inspection Procedure

Inspection Procedure

NOTE:
  • Before performing troubleshooting, inspect the connectors of related circuits.
  • If DTC C1782 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782 first (see DTC C1782 POWER SOURCE VOLTAGE MALFUNCTION  ).
  • Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation (see ELECTRONIC CIRCUIT INSPECTION PROCEDURE ); 2) DTC inspection; and 3) Intelligent tester or Techstream inspection (Data List or Active Test). If no malfunctions are found in other areas, replace the suspension control ECU.
  • If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed (see INITIALIZATION  ).
  1. CHECK DTC 
    1. Clear the DTC (see DTC CHECK / CLEAR  ).
    2. Perform a road test.
    3. Check if DTC C1784 and U0126 are output (see DTC CHECK / CLEAR  )

      Result 

      RESULT CHART

      Result Proceed to
      DTC is not output A
      DTC is output B

    B: GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)  (See HOW TO PROCEED WITH TROUBLESHOOTING )

    A: Go to next Step 

  2. CHECK DTC (BRAKE CONTROL SYSTEM) 
    1. Check if DTC C1231/31 is output (see DTC CHECK / CLEAR ).

      Result 

      RESULT CHART

      Result Proceed to
      DTC is not output A
      DTC is output B

    B: GO TO BRAKE CONTROL SYSTEM (DIAGNOSTIC TROUBLE CODE CHART)  (See DIAGNOSTIC TROUBLE CODE CHART )

    A: Go to next Step 

  3. CHECK STEERING ANGLE SENSOR (POWER SOURCE) 
    1. Disconnect the L21 sensor connector.
    2. Measure the voltage and resistance according to the value (s) in the table below

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Switch Condition Specified Condition
      L21-1 (IG) - Body ground Power switch ON (IG) 11 to 14 V

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      L21-2 (ESS) - Body ground Always Below 1 Ω
    3. Check that the steering angle sensor's connector is not deformed or corroded.

      OK: No deformation or corrosion. 

      HINT:

      If the steering angle sensor's connector is defective, replace the sensor

      Fig 1: Identifying Steering Angle Sensor Connector L21
      G05773753Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next Step 

  4. CHECK STEERING ANGLE SENSOR (DATA LIST) 
    1. Turn the power switch OFF.
    2. Connect the Intelligent tester or Techstream to the DLC3
    3. Turn the power switch ON (IG) and the tester ON
    4. Enter the following menus:
      1. Intelligent tester-Select: DIAGNOSIS/OBD/MOBD / CHASSIS / AIR SUSPENSION / DATA LIST.
      2. Techstream - Select: Chassis / Air suspension / Data List
    5. Check the values by referring to the table below
      1. Intelligent tester

        AIR SUSPENSION 

        DIAGNOSIS NOTE NORMAL CONDITION CHART

        Tester Display Measurement Item/Range Normal Condition
        STEERING ANGLE Steering angle sensor reading /
        min: -49152°
        max: 49150 5°        		 Actual steering angle
        Left turn reading increases
        Right turn reading decreases
      2. Techstream

        Air suspension 

        DIAGNOSIS NOTE NORMAL CONDITION CHART

        Tester Display Measurement Item/Range Normal Condition
        Steering Angle Steering angle sensor reading /
        min: -49152°
        max: 49150 5°
        • Actual steering angle
        • Left turn reading increases
        • Right turn reading decreases

        OK: Steering wheel turning angle value changes. 

    NG: REPLACE STEERING ANGLE SENSOR  (See REMOVAL )

    OK: REPLACE SUSPENSION CONTROL ECU  (See REMOVAL  )

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