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

C296911E02

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.

      Table 1. 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.

    REPLACE POWER STEERING ECU ASSEMBLY

    (Click here)

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

    1. Turn the ignition switch off.

    2. U122610E02

      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
    Table 2. Text in Illustration

    *1

    Front view of wire harness connector

    (to Power Steering ECU)
    Table 3. Result

    Result

    Proceed to

    OK

    A

    NG

    w/o Stop and start system

    B

    w/ Stop and start system

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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

    (Click here)

  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.

    INSTALL GROUND BOLT AND WIRE HARNESS CORRECTLY

    (Click here)

  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.

    INSTALL TERMINAL SCREW AND ECU WIRE SUB-ASSEMBLY CORRECTLY

    (Click here)

  5. CHECK ECU WIRE SUB-ASSEMBLY

    1. U123261E02

      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
    Table 4. Text in Illustration

    *1

    ECU Wire Sub-assembly

    REPLACE POWER STEERING ECU ASSEMBLY

    (Click here)

    REPLACE ECU WIRE SUB-ASSEMBLY

    (Click here)