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Home >> Lexus >> 2009 >> LS 460 RWD >> Repair and Diagnosis >> Steering >> Manual Steering >> Power Steering >> Power Steering System >> PS Warning Light Remains ON >> Inspection Procedure

Inspection Procedure

  1. INSPECT FUSE (E/G RM-IG1-1) 
    1. Remove the E/G RM-IG1-1 fuse from the engine room No. 2 relay block.
    2. Measure the resistance of the fuse.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      E/G RM-IG1-1 fuse Always Below 1 Ω

      NG: REPLACE FUSE 

      OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR 
    1. Start the engine.
    2. Check the indication condition of the PS warning light by wiggling the power steering ECU connector and wire harness up and down, and right and left.

      OK: 

      PS warning light indication condition does not change. 

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      OK: Go to next step 

  3. CHECK CAN COMMUNICATION SYSTEM 
    1. Using the Techstream, check for DTCs and confirm that there are no problems in the CAN communication system (see DIAGNOSIS SYSTEM ).

      Result 

      RESULT CHART

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

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

      A: Go to next step 

  4. CHECK BRAKE CONTROL SYSTEM 
    1. Using the Techstream, check for DTCs and confirm that there are no problems in the brake control system.

      Result 

      RESULT CHART

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

      B: GO TO BRAKE CONTROL SYSTEM  (See HOW TO PROCEED WITH TROUBLESHOOTING )

      A: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (POWER STEERING ECU - BODY GROUND) 
    1. Disconnect the A44 ECU connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Switch Condition Specified Condition
      A44-9 (IG) - Body ground Engine switch on (IG) 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      A44-5 (PGND) - Body ground Always Below 1 Ω
      Fig 1: Identifying A44 ECU Connector
      G06188510Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      OK: Go to next step 

  6. REPLACE POWER STEERING ECU 
    1. Replace the power steering ECU (see REMOVAL  ).
    2. After replacing the power steering ECU, check the illumination condition of the combination meter's PS warning light.

      OK: 

      Engine switch turned on (IG), illuminated → engine started, turns off. 

      NOTE: If replacing the power steering ECU, initialize the rotation angle sensor value and calibrate the torque sensor zero point (see CALIBRATION  ).

      NG: REPLACE COMBINATION METER ASSEMBLY  (See REMOVAL )

      OK: END 

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