DTC U0427: Invalid Data Received From Vehicle Security Control Module

DTC detecting condition: 

Defective data was transmitted from keyless access Control Module.

Trouble symptom: 

Cooperation control of keyless access does not operate properly.

1. CHECK CAN COMMUNICATION HARNESS. 

   Perform the basic diagnostic procedure to check for fault in CAN communication harness. Refer to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

   Was the basic diagnostic procedure performed up to step 7?

   Yes:  Go to  2.

   No:  Perform the basic diagnostic procedure. Refer to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

2. CHECK DTC (OTHER THAN U-CODE). 

   Check the displayed DTC.

   Are DTCs other than U*** displayed?

   Yes:  Perform the diagnosis for DTCs other than the displayed U-code

   No:  Go to  3.

3. CHECK DTC (U-CODE). 

   Check the displayed DTC.

   Is DTC for the bus off or the data no-receive displayed?

   Yes:  Perform the diagnosis for DTCs for the displayed bus off or the data no-receive.

   No:  Go to  4.

4. CHECK DTC (CURRENT MALFUNCTION). 

   Check the displayed DTC.

   Is U0427 a current malfunction?

   Yes:  Go to  5.

   No:  Go to  7.

5. CHECK DTC (CURRENT MALFUNCTION). 
   1. Turn the ignition switch to OFF.
   2. Disconnect the keyless access Control Module connector.
   3. Connect the disconnected connectors.
   4. Read the DTC using Subaru Select Monitor. Refer to LAN SYSTEM (DIAGNOSTICS)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is U0427 a current malfunction?

   Yes:  Go to  6.

   No:  Go to  7.

6. CHECK DTC. 

   Using the Subaru Select Monitor, read DTC of all the systems. Refer to LAN SYSTEM (DIAGNOSTICS)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is U0427 detected in the body integrated unit?

   Replace the keyless access Control Module. Refer to SECURITY AND LOCKS>KEYLESS ACCESS CM .

   No:  Replace the module that the DTC has been detected.

7. CHECK HARNESS. 
   1. Shake the harness, and check for poor contact.
   2. Read the DTC using Subaru Select Monitor. Refer to LAN SYSTEM (DIAGNOSTICS)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is U0427 a current malfunction?

   Yes:  Repair the poor contact of harness, or replace the harness.

   No:  Go to  8.

8. CHECK CONNECTOR. 

   Check the connector used for high speed CAN for poor contact.

   Is there poor contact of connector?

   Yes:  Repair the connector that has poor contact, or replace harness.

   No:  It is possible that temporary poor communication occurs. Delete the DTC.