DTC U0028-437: Vehicle Communication Bus "A"; DTC U0037-438: Vehicle Communication Bus "B": Procedure

CHECK DTC OUTPUT
1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Check for DTCs of all systems by following the prompts on the Techstream screen.
  HINT:
  
  If DTCs other than CAN communication DTCs are output simultaneously, first repair the CAN communication problem, and then perform troubleshooting for other DTCs.
NEXT → See step 2
GO TO CAN COMMUNICATION SYSTEM. Refer to HOW TO PROCEED WITH TROUBLESHOOTING