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Power Steering System: Calibration: Calibration

  1. TORQUE SENSOR ZERO POINT CALIBRATION (USING THE TECHSTREAM) 
    NOTE:

    Perform torque sensor zero point calibration if any of the following conditions occur:

    • The power steering ECU assembly has been replaced.
    • The steering post assembly has been replaced.
    • There is a difference in steering effort between turning left and right.
    1. Inspection before calibration
      1. Turn the power switch off.
      2. Connect the Techstream to the DLC3.
      3. Turn the power switch on (IG).
      4. Turn the Techstream on.
      5. Calibrate the power steering ECU assembly. Enter the following menus: Chassis / EMPS / Data List.
      6. Check the values by referring to the table below.
        EMPS

        Tester Display Measurement Item/Range Normal Condition Diagnostic Note
        IG Power Supply ECU power source voltage/
        Min.: 0.0000V
        Max.: 20.1531 V        		 9 to 16 V Power switch on (IG)

        Standard Voltage

        9 to 16 V

        NOTE:

        If the IG power supply voltage is 9 V or less, calibration cannot be performed. In this case, charge or replace the auxiliary battery, and then perform calibration.

    2. Torque sensor zero point calibration
      NOTE:

      If DTC C1516/16 (Torque Sensor Zero Point Adjustment Incomplete) is stored, the torque sensor zero point cannot be calibrated. Clear the DTCs before starting calibration.

      1. Set the steering wheel to the center point and align the front wheels straight ahead.
      2. Turn the power switch off.
      3. Connect the Techstream to the DLC3.
      4. Turn the power switch on (IG).
      5. Turn the Techstream on.
      6. Enter the following menus: Chassis / EMPS / Utility / Torque Sensor Adjustment.
        NOTE:
        • Do not turn the steering wheel sharply.
        • Do not touch the steering wheel during torque sensor zero point calibration (for 3 seconds).
      7. Check for DTCs. Refer to DTC CHECK / CLEAR .
        NOTE:

        If DTC C1515/15, C1516/16, C1534/34 or C1581/81 is output, perform troubleshooting for the corresponding DTC.

        Result

        Result See Procedure
        DTC C1515/15 is output. Refer to DTC C1515/15: Torque Sensor Zero Point Adjustment is not Initialized
        DTC C1516/16 is output. Refer to DTC C1516/16: Torque Sensor Zero Point Adjustment Incomplete
        DTC C1534/34 is output. Refer to DTC C1531/31: EPS ECU Circuit Malfunction; DTC C1532/32: EPS ECU Circuit Malfunction; DTC C1533/33: EPS ECU Circuit Malfunction; DTC C1534/34: EPS ECU Circuit Malfunction; DTC C1535/35: Steering Wheel Location Data Error
        DTC C1581/81 is output. Refer to DTC C1581/81: Assist Map Un-Writing
  2. TORQUE SENSOR ZERO POINT CALIBRATION (USING SST CHECK WIRE) 
    NOTE:

    Calibrate the torque sensor zero point if any of the following has occurred:

    • The power steering ECU assembly has been replaced.
    • The steering post assembly has been replaced.
    • Steering effort differs between left and right.
    1. Check for DTCs.
      1. Check for DTCs. Refer to DTC CHECK / CLEAR .
        NOTE:
        • If DTC C1516/16 (Torque Sensor Zero Point Adjustment Incomplete) is stored, the torque sensor zero point cannot be calibrated. Clear the DTC before starting calibration.
        • If DTCs other than C1516/16 is output, refer to the Diagnostic Trouble Code Chart. Refer to DIAGNOSTIC TROUBLE CODE CHART .
    2. Perform pre-calibration check.
      1. Turn the power switch off.
      2. Disconnect the L188 power steering ECU assembly connector.
      3. Turn the power switch on (IG).
      4. Measure the voltage according to the value(s) in the table below.
        Fig 1: Inspecting L188 Connector Terminals
        GTY329580Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard Voltage

        Tester Connection Condition Specified Condition
        L188-6 (IG) - Body ground Power switch on (IG) 9 to 16 V
        NOTE:

        If the IG power supply voltage is 9 V or less, calibration cannot be performed. In this case, charge or replace the auxiliary battery, and then perform calibration.

      5. Turn the power switch off.
      6. Connect the L188 power steering ECU assembly connector.
        TEXT IN ILLUSTRATION

        *a Front view of wire harness connector
        (to power steering ECU assembly)
    3. Clear sensor calibration value.
      1. Set the steering wheel to the center point and align the front tires straight ahead.
      2. Turn the power switch off.
      3. Using SST, connect terminals 12 (TS) and 4 (CG) of the DLC3.
        Fig 2: Identifying DLC3 Connector Terminals
        GTY343314Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        • SST: 09843-18040 
        NOTE:

        Connect the terminals to the correct positions to avoid a malfunction.

        TEXT IN ILLUSTRATION

        *1 DLC3
      4. Turn the power switch on (IG) and then connect and disconnect terminals 13 (TC) and 4 (CG) at least 20 times in 20 seconds.
      5. Check that the EPS warning light blinks and then remains illuminated.
        Fig 3: Identifying P/S Warning Light
        GTY323512Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        HINT: 

        The EPS warning light illumination indicates that DTCs C1515/15 has been stored.

      6. Turn the power switch off.
        NOTE:

        After erasing the sensor calibration value zero point calibration cannot be performed if the power switch on (IG).

        TEXT IN ILLUSTRATION

        *1 EPS Warning Light
    4. Perform torque sensor zero point calibration.
      NOTE:

      As torque sensor zero point calibration cannot be performed if DTC C1515/15 has not been stored, be sure to perform sensor calibration value erasure before performing torque sensor zero point calibration.

      1. Set the steering wheel to the center point and align the front tires straight ahead.
      2. Turn the power switch off.
      3. Using SST, connect terminals 12 (TS) and 4 (CG) of the DLC3.
        Fig 4: Identifying DLC3 Connector Terminals
        GTY343314Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        • SST: 09843-18040 
        TEXT IN ILLUSTRATION

        *1 DLC3
      4. Turn the power switch on (IG) and then connect terminals 13 (TC) and 4 (CG).
        NOTE:

        Do not touch the steering wheel during calibration (for 3 seconds).

        HINT: 

        The EPS warning light remains illuminated even after calibration has completed.

      5. With terminals 12 (TS) and 4 (CG), and 13 (TC) and 4 (CG) connected, and the power switch on (IG), continue to perform rotation angle sensor initialization.
  3. ASSIST MAP WRITING (USING THE TECHSTREAM) 
    NOTE:

    Perform assist map writing if any of the following conditions occur:

    • The power steering ECU assembly has been replaced.
    1. Turn the power switch off.
    2. Connect the Techstream to the DLC3.
    3. Turn the power switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Chassis / EMPS / Utility / Signal Check.

      HINT: 

      • Follow the instructions on the Techstream to perform Signal Check.
      • With DTC C1581/81 output, performing Signal Check will cause the power steering ECU assembly to enter Test Mode and the assist map will be written automatically.
    6. Wait for at least 5 seconds.
    7. Check for DTCs. Refer to DTC CHECK / CLEAR .

      HINT: 

      After writing the assist map, if DTC C1581/81 is output, perform the troubleshooting procedure for DTC C1581/81. Refer to DTC C1581/81: Assist Map Un-Writing .

  4. ASSIST MAP WRITING (USING SST CHECK WIRE) 
    NOTE:

    Perform assist map writing if any of the following conditions occur:

    • The power steering ECU assembly has been replaced.

    HINT: 

    If DTC C1581/81 is output after torque sensor zero point calibration, perform assist map writing.

    1. Turn the power switch off.
      Fig 5: Identifying DLC3 Connector Terminals
      GTY322350Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 DLC3
    2. Using SST, connect terminals 12 (TS) and 4 (CG) of the DLC3.
      • SST: 09843-18040 
      NOTE:

      Connect the terminals correctly to avoid a malfunction.

    3. Turn the power switch on (IG).
    4. Wait for 5 seconds or more.
    5. Check for DTCs. Refer to DTC CHECK / CLEAR .

      HINT: 

      After writing the assist map, if DTC C1581/81 is output, perform the troubleshooting procedure for DTC C1581/81. Refer to DTC C1581/81: Assist Map Un-Writing .

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