DTC U0073 Control Module Communication Bus "A" Off: Wiring Diagram

CAN communication system. See appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: CAN Communication System - Wiring Diagram

G08585509

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK DTC. Start the engine. Using the Subaru Select Monitor, read DTC of all the systems.	Is U0073 a current malfunction?	Go to step 2 .	It may be a temporary poor contact. Perform the clear memory.
2 CHECK CAN COMMUNICATION CIRCUIT. Check CAN communication circuit. Refer to BUS "A" (MAIN-CAN) .	Is CAN communication circuit faulty?	Repair the faulty portion, following the diagnosis procedure.	Go to step 3 .
3 CHECK DTC. Start the engine. Using the Subaru Select Monitor, read DTC of all the systems.	Is U0073 a current malfunction?	Go to step 4 .	System is normal.
4 CHECK CONTROL MODULE. Turn the ignition switch to OFF. Disconnect the control modules other than body integrated unit in order. NOTE: When disconnecting ECM or VDC CM, connect resistance of 120 Ω between CAN Hi and CAN Lo as an alternative of end resistance. Turn the ignition switch to ON. Using the Subaru Select Monitor, read DTC of CAN system.	Is there any control module that U0073 is not detected as current malfunction?	Replace the control module.	Repeat 1) to 4) in step 4 until U0073 is not detected.