CAN COMMUNICATION SYSTEM Power Steering ECU Communication Stop Mode

DTC Code DTC Name
Power Steering ECU Communication Stop Mode

DESCRIPTION

Detection Item

Symptom

Trouble Area

Power Steering ECU Communication Stop Mode

Either condition is met:

  • "Power Steering (EPS)" is not displayed on the "CAN Bus Check" screen (Click here).

  • Communication system DTCs (DTCs that start with U) that are output correspond to "Power Steering ECU Communication Stop Mode" in "DTC Combination Table" (Click here).

  • Power steering ECU assembly CAN branch wire or connector

  • Power source circuit of power steering ECU assembly

  • Power steering ECU assembly ground circuit

  • ECU wire sub-assembly

  • Power steering ECU assembly

WIRING DIAGRAM

C350767E01

CAUTION / NOTICE / HINT

Note:
  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output (Click here).

  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work (Click here).

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

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed (Click here).

Tip:
  • Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

  1. CHECK FOR OPEN IN CAN BUS WIRE (POWER STEERING ECU ASSEMBLY CAN BRANCH WIRE)

    1. U122832E02

      Disconnect the cable from the negative (-) battery terminal.

    2. Disconnect the power steering ECU assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      H49-2 (CANH) - H49-8 (CANL)

      Cable disconnected from negative (-) battery terminal

      54 to 69 Ω

      Table 1. Text in Illustration

      *a

      Front view of wire harness connector

      (to Power Steering ECU Assembly)

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO POWER STEERING ECU ASSEMBLY (CANH, CANL)

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

    1. U123145E02

      Connect the cable to the negative (-) battery terminal.

      Note:

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected (Click here).

    2. Disconnect the ECU wire sub-assembly connector.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      Az1-1 - Body ground

      Always

      11 to 14 V

      Table 2. Text in Illustration

      *a

      Front view of wire harness connector

      (to ECU Wire Sub-assembly)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  3. CHECK GROUND BOLT AND WIRE HARNESS

    1. Check that the ground bolt and wire harness are installed correctly (Click here).

      OK

      Ground bolt and wire harness are installed correctly.

    INSTALL GROUND AND WIRE HARNESS CORRECTLY

  4. CHECK TERMINAL SCREW AND ECU WIRE SUB-ASSEMBLY

    1. Remove the power terminal cover from the power steering ECU assembly (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

  5. CHECK ECU WIRE SUB-ASSEMBLY

    1. U123260E02

      Remove the z21 and z22 terminal screws from the power steering ECU assembly (Click here).

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

      Standard Resistance

      Tester Connection

      Switch Condition

      Specified Condition

      z21-1 (PGND) - Body ground

      Always

      Below 1 Ω

      z22-1 (PIG) - Az1-1

      Always

      Below 1 Ω

      z22-1 (PIG) or Az1-1 - Body ground

      Always

      10 kΩ or higher

    REPLACE ECU WIRE SUB-ASSEMBLY

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

    1. U122833E02

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

      Standard Voltage

      Table 3. w/ Stop and Start System

      Tester Connection

      Switch Condition

      Specified Condition

      H49-5 (IG) - Body ground

      Ignition switch ON

      10.5 to 16 V

      Table 4. w/o Stop and Start System

      Tester Connection

      Switch Condition

      Specified Condition

      H49-5 (IG) - Body ground

      Ignition switch ON

      11 to 14 V

      Table 5. Text in Illustration

      *a

      Front view of wire harness connector

      (to Power Steering ECU Assembly)

      Table 6. Result

      Result

      Proceed to

      OK

      A

      NG (w/ Stop and Start System)

      B

      NG (w/o Stop and Start System)

      C

    REPLACE POWER STEERING ECU ASSEMBLY

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    REPLACE STOP AND START SYSTEM