ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1203

DTC Code DTC Name
C1203 ECM Communication Circuit Malfunction

DESCRIPTION

The rear differential lock identification signal is sent from the 4 wheel drive control ECU to the skid control ECU (brake actuator assembly) via the CAN communication system.

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

Either of the following is detected:


  1. The rear differential lock identification signal sent from the 4 wheel drive control ECU does not match the information stored in the skid control ECU.

  2. No system information stored in the skid control ECU.

  3. Incorrect installation of the skid control ECU or 4 wheel drive control ECU.

  • 4 wheel drive control ECU malfunction or 4 wheel drive control ECU with incorrect part number installed

  • Skid control ECU (Brake actuator assembly)

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (brake actuator assembly), perform Test Mode (Signal Check) to acquire the rear differential lock identification information.

Click here

Tech Tips

When DTC U0114 is output together with DTC C1203, inspect and repair the trouble areas indicated by DTC U0114 first.

Click here

PROCEDURE


  1. CHECK PART NUMBER (4 WHEEL DRIVE CONTROL ECU)


    1. Check that a proper 4 wheel drive control ECU is installed.

      Result
      Proceed to
      Proper 4 wheel drive control ECU is installed
      Proper 4 wheel drive control ECU are not installed

    Proper 4 wheel drive control ECU are not installed

    REPLACE 4 WHEEL DRIVE CONTROL ECU Click here

    Proper 4 wheel drive control ECU is installed

  2. CHECK BRAKE ACTUATOR ASSEMBLY


    1. Check if the brake actuator assembly had been replaced before the DTC was recorded.

      Result
      Proceed to
      The brake actuator assembly is not replaced
      The brake actuator assembly is replaced

    The brake actuator assembly is replaced

    PERFORM TEST MODE (SIGNAL CHECK) Click here

    The brake actuator assembly is not replaced

  3. RECONFIRM DTC


    1. Clear the DTC.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the ignition switch off.

    3. Check if the same DTC is recorded.

      Click here


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

    DTC C1203 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC C1203 is output

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  4. PERFORM TEST MODE (SIGNAL CHECK)


    1. Perform Test Mode (signal check).

      Click here

      Tech Tips

      After replacing the skid control ECU (brake actuator assembly), it is necessary to perform registration of rear differential lock identification information. Rear differential lock identification information is automatically acquired when the system enters test mode.

      Result
      Proceed to
      NEXT

    NEXT

  5. RECONFIRM DTC


    1. Clear the DTC.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the ignition switch off.

    3. Check if the same DTC is recorded.

      Click here


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

    DTC C1203 is not output

    END

    DTC C1203 is output

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here