DTC U1C0B: Invalid Authentication Data Received From Brake System Control Module Ch-Bus

DTC detecting condition: 

Authentication communication between the electric brake booster control module and the control module in which the DTC was detected failed.

Trouble symptom: 

The warning light of the control module in which the DTC was detected illuminates.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor, perform the clear memory of the control module in which the DTC was detected. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   3. Using the Subaru Select Monitor, read the DTC of the control module in which it was detected. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC U1C0B displayed? (Current code)

   Yes:  Go to  2.

   No:  Currently, it is normal.

2. PERFORM MODULE REGISTRATION (VERIFICATION)  .

   Using the Subaru Select Monitor, perform module registration (verification) of the control module in which the DTC was detected.

   Is the module registration (verification) completed successfully? (Was [Key verification is complete. Please press the OK button.] displayed?)

   Yes:  Go to  6.

   No:  Go to  3.

3. CHECK ERROR SCREEN  .

   Check the error message displayed on the Subaru Select Monitor.

   Is the error message as follows?

   • Diagnostic communication error occurred. End processing. Error occurred in the following ECM.

   Yes:  In order to check poor contact of the failed module, reconnect it, Go to  1. If it fails again, replace the failed module and perform registration.

   No:  Go to  4.

4. CHECK ERROR SCREEN  .

   Check the error message displayed on the Subaru Select Monitor.

   Is the error message as follows?

   • MAC key verification failed. End processing.

   Yes:  In order to check poor contact of the failed module, reconnect it, Go to  1. If it fails again, replace the failed module and perform registration.

   No:  Go to  5.

5. CHECK ERROR SCREEN  .

   Check the error message displayed on the Subaru Select Monitor.

   Is the error message as follows?

   • There is an ECM in which the DTC of key update failure was detected. End processing.

   If the above error message is displayed and the diagnosis for the displayed DTC B1E00 is necessary, go to  A.

   If the above error message is displayed and the diagnosis for the displayed DTC C1E00 is necessary, go to  B.

   If the above error message is displayed and the diagnosis for the displayed DTC P1E00 is necessary, go to  C.

   If the above error message is not displayed, go to  D.

   1. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1E00 REGISTRATION FAULT OF AUTHENTICATION UNIT .
   2. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC C1E00 REGISTRATION FAULT OF AUTHENTICATION UNIT .
   3. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC P1E00 REGISTRATION FAULT OF AUTHENTICATION UNIT .
   4. Perform the procedure from the beginning. Go to  1.
6. CHECK DTC  .
   1. Using the Subaru Select Monitor, perform the clear memory of the control module in which the DTC was detected. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   2. Using the Subaru Select Monitor, read the DTC of the control module in which it was detected. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC U1C0B displayed? (Current code)

   Yes:  Go to  7.

   No:  Finish the diagnosis.

7. CHECK FAILED MODULE  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the ground terminal from battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   3. Disconnect the DCM connector.
   4. Connect the ground terminal to battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   5. Turn the ignition switch to ON.
   6. Using the Subaru Select Monitor, perform the clear memory of the control module in which the DTC was detected. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   7. Using the Subaru Select Monitor, read the DTC of the control module in which it was detected. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC U1C0B displayed? (Current code)

   Yes:  Go to  8.

   No:  Replace the DCM. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE .

8. CHECK FAILED MODULE  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the ground terminal from battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   3. Disconnect the cockpit control module connector.
   4. Connect the ground terminal to battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   5. Turn the ignition switch to ON.
   6. Using the Subaru Select Monitor, perform the clear memory of the control module in which the DTC was detected. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   7. Using the Subaru Select Monitor, read the DTC of the control module in which it was detected. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC U1C0B displayed? (Current code)

   Yes:  Go to  9.

   No:  Replace the cockpit control module. Ref. to ENTERTAINMENT & MONITORING>COCKPIT DISPLAY .

9. CHECK BUS LINE  .

   Visually check if an incorrect, non-SUBARU genuine module is installed in the CH bus line.

   Is an incorrect module installed?

   Yes:  Go to  10.

   No:  In order to check poor contact of the detected control module, reconnect it, Go to  1. If it is detected again, replace the detected control module and perform registration.

10. CHECK DTC  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the ground terminal from battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
    3. Remove the incorrect module.
    4. Connect the ground terminal to battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
    5. Turn the ignition switch to ON.
    6. Using the Subaru Select Monitor, perform the clear memory of the control module in which the DTC was detected. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
    7. Using the Subaru Select Monitor, read the DTC of the control module in which it was detected. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    Is DTC U1C0B displayed? (Current code)

    Yes:  In order to check poor contact of the detected control module, reconnect it, Go to  1. If it is detected again, replace the detected control module and perform registration.

    No:  Finish the diagnosis.