ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1203

DTC Code DTC Name
C1203 ECM Communication Circuit

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) stores identification information sent from other ECUs when the vehicle is shipped from the factory and changes the control constant for each system (ABS, VSC, TRC, etc.) based on the identification information.

Note

DTC C1203 is output when an incorrect ECU is installed. If initialization is performed and learning occurs with an incorrect ECU installed, operations and functions will differ from those stored when the vehicle was shipped from the factory. Therefore, make sure that learning occurs properly.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1203 ECM Communication Circuit 1161

Either of the following is detected:


  1. Identification information sent from other ECUs does not match with the value stored when shipped from the factory.

  2. Identification information sent from other ECUs is not stored when shipped from the factory.

  • Other ECUs are not installed correctly

  • Skid control ECU (brake booster with master cylinder assembly)

Electronically controlled brake system DTC

Tech Tips


  • The DTC is cleared when the conditions return to normal.

  • This DTC is stored when incorrect identification information is detected and is not due to an ECM communication error.
DTC Detection Conditions: C1203 INF Code: 1161
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition - - -
Malfunction Status Identification information sent from other ECUs does not match with the value stored when shipped from the factory. ○ -
Identification information sent from other ECUs is not stored when shipped from the factory. - ○
Detection Time - -
Number of Trips 1 trip 1 trip

Tech Tips

DTC will be output when conditions for either of the patterns in the table above are met.

CAUTION / NOTICE / HINT

Note

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

Click here

PROCEDURE


  1. CHECK PART NUMBER


    1. Check that the proper hybrid vehicle control ECU and main body ECU (multiplex network body ECU) are installed.

      OK
      Proper ECUs are installed.

    2. Check if the hybrid vehicle control ECU and main body ECU (multiplex network body ECU) were replaced before the DTC was recorded.

      OK
      ECUs were not replaced.
      Result
      Result Proceed to
      OK A
      NG (A proper hybrid vehicle control ECU is not installed and/or the hybrid vehicle control ECU was replaced.) B
      NG (A proper main body ECU (multiplex network body ECU) is not installed and/or the main body ECU (multiplex network body ECU) was replaced.) C

    B

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

    C

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: Click here
    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for RHD: Click here

    A

  2. PERFORM INITIALIZATION


    1. Perform linear solenoid valve offset learning, ABS holding solenoid valve learning and system information memorization.

      Click here


      Chassis > ABS/VSC/TRC > Utility
      Tester Display
      ECB Utility

    2. Perform yaw rate and acceleration sensor zero point calibration.

      Click here


      Chassis > ABS/VSC/TRC > Utility
      Tester Display
      Test Mode

      Tech Tips


      • After installing a new skid control ECU (brake booster with master cylinder assembly), before performing linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization, DTC C1203 will be output.

      • If linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization are not performed, DTC C1203 will be output after the data stored in the skid control ECU (brake booster with master cylinder assembly) is cleared by performing "Reset Memory" using GTS.

      Result
      Proceed to
      NEXT

    NEXT

  3. RECONFIRM DTC


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the power switch off.

    3. Turn the power 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 output. (for LHD) A
      DTC C1203 is output. (for RHD) B
      DTC C1203 is not output. C

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

    C

    END