Causes and Fixes U0073 Code: Control Module Communication Bus "A" Off

How to fix a U0073 Code: Control Module Communication Bus "A" Off The U0073 means control modules and CAN Bus are not communicating correctly. The CAN (Controller Area Network) is a protocol that allows the ECM, PCM, TCM, and ABS modules to communicate with each other. Diagnosing a U0073 can be difficult and time-consuming. Possible Causes of a U0073 Code: Blown Fuse Issues with Alternator Charging or Battery Wiring Issue Such as Damaged Wires or Poor Connections Faulty Control Module By using this information user assumes all risk of use.