VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1203

DTC Code DTC Name
C1203 ECM Communication Circuit

DESCRIPTION

This circuit is used to send TRC and VSC operation information from the skid control ECU (brake actuator assembly) to the ECM, and engine control information from the ECM to the skid control ECU (brake actuator assembly) through the CAN communication.

DTC No. Detection Item DTC Detection Condition Trouble Area
C1203 ECM Communication Circuit

Any of the following is detected:


  1. Engine, drive source and destination information sent from the ECM does not match the information of the skid control ECU or there is no information in memory.

  2. The presence or absence of the VGRS ECU (front steering control ECU) does not match the information stored in the skid control ECU.

  3. The presence or absence of the DRS ECU (rear steering control ECU) does not match the information stored in the skid control ECU.

  • Incorrect ECM installed, or ECM malfunction

  • Incorrect VGRS ECU (front steering control ECU) installed, or ECU malfunction

  • Incorrect DRS ECU (rear steering control ECU) installed, or ECU malfunction

  • Skid Control ECU (brake actuator assembly)

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information.

Click here

PROCEDURE


  1. CHECK PART NUMBER (ECM)


    1. Check that the proper ECM is installed.

      OK
      Proper ECM is installed.

    2. Check if the ECM was replaced before the DTC was stored.

      OK
      ECM was not replaced.
      Result
      Result Proceed to
      OK (w/ VGRS system) A
      OK (w/o VGRS system) B
      NG (A proper ECM is not installed and/or the ECM was replaced.) C

    B

    GO TO STEP 4 Click here

    C

    REPLACE ECM for 2GR-FKS: Click here
    REPLACE ECM for 8AR-FTS: Click here

    A

  2. CHECK PART NUMBER (FRONT STEERING CONTROL ECU)


    1. Check that a proper VGRS ECU (front steering control ECU) is installed.

      OK
      Proper VGRS ECU (front steering control ECU) is installed.

    2. Check if the VGRS ECU (front steering control ECU) had been replaced before the DTC was stored.

      OK
      VGRS ECU (front steering control ECU) had not been replaced.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FRONT STEERING CONTROL ECU for LHD: Click here
    REPLACE FRONT STEERING CONTROL ECU for RHD: Click here

    OK

  3. CHECK PART NUMBER (REAR STEERING CONTROL ECU)


    1. Check that a correct DRS ECU (rear steering control ECU) is installed.

      OK
      The correct DRS ECU (rear steering control ECU) is installed.

    2. Check if the DRS ECU (rear steering control ECU) had been replaced before the DTC was stored.

      OK
      DRS ECU (rear steering control ECU) had not been replaced.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE REAR STEERING CONTROL ECU Click here

    OK

  4. CHECK PART NUMBER (BRAKE ACTUATOR ASSEMBLY)


    1. Check that a proper skid control ECU (brake actuator assembly) is installed.

      OK
      Proper skid control ECU (brake actuator assembly) is installed.

    2. Check if the skid control ECU (brake actuator assembly) had been replaced before the DTC was stored.

      OK
      Skid control ECU (brake actuator assembly) had not been replaced.
      Result
      Result Proceed to
      OK A
      NG (The skid control ECU (brake actuator assembly) had been replaced.) B
      NG (A proper skid control ECU (brake actuator assembly) is not installed.) C

    B

    PERFORM ZERO POINT CALIBRATION AND STORE SYSTEM INFORMATION Click here

    C

    REPLACE BRAKE ACTUATOR ASSEMBLY for LHD: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY for RHD: Click here

    A

  5. CLEAR AND STORE SYSTEM INFORMATION


    1. Clear the system information.

      Click here


      Chassis > ABS/VSC/TRC > Utility
      Tester Display
      Reset Memory

    2. Store the system information.

      Click here


      Chassis > ABS/VSC/TRC > Utility
      Tester Display
      Test Mode
      Result
      Proceed to
      NEXT

    NEXT

  6. RECONFIRM DTC


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the engine switch off.

    3. Turn the engine switch on (IG).

    4. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C1203 is not output. A
      DTC C1203 is output. B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY for LHD: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY for RHD: Click here