POWER STEERING SYSTEM EPS Warning Light Circuit

DESCRIPTION

If the power steering ECU assembly detects a malfunction, the EPS warning light comes on. At this time, the power steering ECU assembly stores a DTC in its memory.

WIRING DIAGRAM

A01EU14E03

INSPECTION PROCEDURE

Note

If the power steering ECU assembly has been replaced with a new one, perform assist map writing and torque sensor zero point calibration Click here.

Tech Tips

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK CONNECT CONNECTOR OR INSTALL GROUND WIRE


    1. Check the connection condition of the ECU wire sub-assembly and power steering ECU assembly connectors.

      OK
      The ECU wire sub-assembly and power steering ECU assembly connectors are securely connected.

    2. Check that the ground wire is securely installed with the bolt Click here.

      OK
      The ground wire is securely installed with the bolt.

    NG

    CONNECT CONNECTOR OR INSTALL GROUND WIRE Click here

    OK

  2. CHECK CAN COMMUNICATION SYSTEM


    1. Check for DTCs Click here.

      OK
      DTC is not output.

    NG

    GO TO CAN COMMUNICATION SYSTEM Click here

    OK

  3. READ VALUE USING INTELLIGENT TESTER


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

    5. Enter the following menus: Chassis / EMPS / Data List.

    6. Select the item "IG power supply" in the Data List and read the value displayed on the intelligent tester.

      EMPS
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      IG power supply

      IG power supply/

      Min.: 0.0000 V

      Max.: 20.1531 V

      		 9 to 16 V Ignition switch ON
      OK
      The normal condition value is displayed on the intelligent tester.

    NG

    CHECK HARNESS AND CONNECTOR (BATTERY - ECU WIRE SUB-ASSEMBLY) Click here

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here

  4. CHECK HARNESS AND CONNECTOR (BATTERY - ECU WIRE SUB-ASSEMBLY)


    1. A01EWHZE05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECU Wire Sub-assembly)

      Disconnect the Ij2 connector from the ECU wire sub-assembly.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      Ij2-5 (IG) - Body ground Ignition switch ON 9 to 16 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BODY GROUND)


    1. A01EX0PE07
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Power Steering ECU Assembly)

      Disconnect the j2 connector from the power steering ECU assembly.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      j2-2 (PGND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE ECU WIRE SUB-ASSEMBLY Click here

    OK

  6. CHECK ECU WIRE SUB-ASSEMBLY


    1. A01ESYRE05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Power Steering ECU Assembly)
      *b

      Front view of wire harness connector

      (to Vehicle Wire Harness)

      Disconnect the j1 connector from the power steering ECU assembly.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      j1-1 (IG) - Ij2-5 (IG) Always Below 1 Ω

    NG

    REPAIR OR REPLACE ECU WIRE SUB-ASSEMBLY Click here

    OK

  7. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

    5. Enter the following menus: Body / Combination Meter / Active Test.

    6. Perform the Active Test of the combination meter assembly using the intelligent tester.

      Combination Meter
      Tester Display Test Part Control Range Diagnostic Note
      Indicat. EPS EPS warning light OFF or ON Confirm that the vehicle is stopped with the engine idling

    7. Check that the EPS warning light operates in accordance with the Active Test.

      Tech Tips

      Reconnect the connectors and restore the vehicle to its previous condition before checking the combination meter assembly.


    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here