POWER STEERING SYSTEM, Diagnostic DTC:C1551

DTC Code DTC Name
C1551 IG Power Supply Voltage Malfunction

DESCRIPTION

The power steering ECU determines whether the ignition switch status is ON or off through the IG power supply circuit.

DTC Code DTC Detection Condition Trouble Area
C1551 An IG power supply circuit malfunction inside the ECU.

  • ECU-IG NO. 1 fuse (w/o Stop and start system)

  • IG power supply circuit

  • Power steering ECU assembly

  • ECU wire sub-assembly

WIRING DIAGRAM

A002M1BE02

CAUTION / NOTICE / HINT

Note


  • If the power steering ECU assembly is replaced, perform the assist map writing Click here.

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

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (IG POWER SUPPLY)


    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.

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

      ECU power source voltage/

      Min.: 0.0000 V

      Max.: 20.1531 V

      		 11 to 14 V The ignition switch is ON.
      OK
      The normal condition value is displayed the intelligent tester.

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here

    NG

  2. CHECK HARNESS AND CONNECTOR (POWER STEERING ECU - BATTERY)


    1. Turn the ignition switch off.

    2. A002M0YE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Steering ECU)

      Disconnect the H49 power steering ECU connector.

    3. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      H49-5 (IG) - Body ground Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG w/o Stop and start system B
      w/ Stop and start system C

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    C

    GO TO STOP AND START SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    A

  3. CHECK GROUND BOLT AND WIRE HARNESS


    1. Turn the ignition switch off.

    2. Check that the ground bolt and wire harness are installed correctly Click here.

      OK
      Ground bolt and wire harness are installed correctly.

    NG

    INSTALL GROUND BOLT AND WIRE HARNESS CORRECTLY Click here

    OK

  4. CHECK TERMINAL SCREW AND ECU WIRE SUB-ASSEMBLY


    1. Remove the power terminal cover from the power steering ECU Click here.

    2. Check that the z21 terminal screw and ECU wire sub-assembly are installed correctly Click here.

      OK
      Terminal screw and ECU wire sub-assembly are installed correctly.

    NG

    INSTALL TERMINAL SCREW AND ECU WIRE SUB-ASSEMBLY CORRECTLY Click here

    OK

  5. CHECK ECU WIRE SUB-ASSEMBLY


    1. A002M9IE02
      Text in Illustration
      *1 ECU Wire Sub-assembly

      Remove the z21 terminal screw from the power steering ECU Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      z21-1 (PGND) - Body ground Always Below 1 Ω

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here

    NG

    REPLACE ECU WIRE SUB-ASSEMBLY Click here