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

A01G7UAE06

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 electric power steering column sub-assembly and power steering ECU assembly connectors.

      OK
      The electric power steering column 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
      DTCs are not output.

    NG

    GO TO CAN COMMUNICATION SYSTEM Click here

    OK

  3. READ VALUE USING GTS


    1. Turn the engine switch off.

    2. Connect the GTS to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the GTS 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 GTS.

      EMPS
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      IG Power Supply

      IG power source voltage/

      Min.: 0.0000 V

      Max.: 20.1531 V

      		 8 to 16 V Engine switch on (IG)
      OK
      The normal condition value is displayed on the GTS.

    NG

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

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here

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


    1. A01G71EE11
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECU Wire Sub-assembly)

      Disconnect the Hc2 ECU wire sub-assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      Hc2-5 (IG) - Body ground Engine switch on (IG) 8 to 16 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK ECU WIRE SUB-ASSEMBLY (POWER STEERING ECU ASSEMBLY - BODY GROUND)


    1. A01G7RNE13
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Power Steering ECU Assembly)

      Disconnect the c2 power steering ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      c2-2 (PGND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE ECU WIRE SUB-ASSEMBLY Click here

    OK

  6. INSPECT ECU WIRE SUB-ASSEMBLY


    1. A01G8MME10
      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 c1 power steering ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      c1-1 (IG) - Hc2-5 (IG) Always Below 1 Ω

    NG

    REPAIR OR REPLACE ECU WIRE SUB-ASSEMBLY Click here

    OK

  7. INSPECT COMBINATION METER ASSEMBLY


    1. Reconnect the c1 and c2 power steering ECU assembly connectors.

    2. Perform the Active Test of the combination meter assembly using the GTS Click here.

    3. Check the combination meter assembly.

      OK
      The EPS warning light turns on or off in accordance with the GTS operation.

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.


    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here