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Home >> Lexus >> 2004 >> GX 470 >> Repair and Diagnosis >> Suspension >> Electronic Suspension >> Electronic Modulated Suspension & Rear Air Suspension System - Diagnosis >> DTC C1777/77: Steering Angle Sensor Circuit >> Inspection Procedure

Inspection Procedure

HINT:

Start the inspection from step 1 when using the hand-held tester, and start from step 2 when not using the hand-held tester.

  1. READ VALUE OF HAND-HELD TESTER 
    1. Connect the hand-held tester to DLC3.
    2. Turn the ignition switch ON, and push the hand-held tester main switch ON.
    3. Select the item "STEERING ANGLE" in the DATA LIST, and read its value displayed on the hand-held tester.
    4. Check that the steering wheel turning angle value of the steering angle position sensor displayed on the hand-held tester changes when turning the steering wheel.

    Standard: Steering wheel turning angle value changes. 

    1. OK: CHECK AND REPLACE SUSPENSION CONTROL ECU (See  ELECTRONIC CIRCUIT INSPECTION PROCEDURE  ) 
    2. NG: GO TO NEXT STEP. 
  2. CHECK HARNESS AND CONNECTOR (STEERING SENSOR) 
    1. Disconnect the steering sensor connector.
    2. Turn the ignition switch to ON, and measure voltage between terminal 1 (IG1) and 2 (ESS) and between terminal 2 (ESS) and 9 (BAT) of the steering sensor harness side connector.
      Fig 1: Measuring Voltage Between terminal 1 (IG1) And 2 (ESS)
      G01421640Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Standard: 10 to 14 V 

    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: GO TO NEXT STEP. 
  3. INSPECT STEERING SENSOR 
    1. Disconnect the steering angle sensor connector.
    2. Apply battery positive voltage between terminal 1 (IG and 2 (ESS) and between terminal 2 (ESS) and 9 (BAT).
    3. Connect the oscilloscope to the terminal 4 (SS2+) and 12 (SS2-) of the steering angle sensor.
    4. Turn the steering column shaft slowly and check the signal waveform.

      Standard: 

      Fig 2: Inspecting Steering Sensor
      G01421641Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 3: Checking Signal Waveform
      G01421642Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    Above signal waveform does not repeat ON and OFF regularly and this ON-OFF interval changes depending on the data.

    1. NG: REPLACE STEERING SENSOR 
    2. OK: GO TO NEXT STEP. 
  4. CHECK HARNESS AND CONNECTOR (STEERING SENSOR - SUSPENSION CONTROL ECU) 
    1. Check for open and short circuit in the harness and the connector between the steering sensor and the suspension control ECU (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: GO TO NEXT STEP. 

      CHECK AND REPLACE SUSPENSION CONTROL ECU (See  ELECTRONIC CIRCUIT INSPECTION PROCEDURE  ) 

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