DTC U0129: Lost Communication With Brake System Control Module

DTC detecting condition:

No data is received from VDC Control Module.

Trouble symptom:

ABS warning light and VDC warning light illuminate.

CAUTION:

Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to LAN SYSTEM (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION

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

Was the basic diagnostic procedure performed up to step 7?

Yes : Go to 2.

No : Perform the basic diagnostic procedure. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE
CHECK DTC (OTHER THAN U-CODE) .
Check the displayed DTC.

Is DTC other than U**** displayed? (Current code)

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

No : Go to 3.
CHECK DTC (CURRENT CODE) .
Check the displayed DTC.

Is DTC U0129 displayed? (Current code)

Yes : Go to 4.

No : Go to 6.
CHECK DTC .
1. Check CAN communication circuit. Ref. to LAN SYSTEM (DIAGNOSTICS)>CAN COMMUNICATION CIRCUIT CHECK
2. Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)
Is DTC U0129 displayed? (Current code)

Yes : Go to 5.

No : Go to 6.
CHECK DTC .
Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)

Is DTC U0129 detected in several modules? (Current code)

Yes : Replace the VDC Control Module. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDC CONTROL MODULE & H/U)

No : Replace the module that the DTC has been detected.
CHECK HARNESS .
1. Shake the harness, and check for poor contact.
2. Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)
Is DTC U0129 displayed? (Current code)

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

No : Go to 7.
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.