U0073 Control Module Communication Bus A Off
What does U0073 mean?
U0073 — Control Module Communication Bus A Off. This is an OBD-II diagnostic trouble code a scanner retrieves when your vehicle's computer detects control module communication bus a off. The level of risk depends on how the vehicle is currently running and how long you've been driving with the light on.
Common causes of U0073
- Shorted or open CAN bus wiring
- Failed module shorting the communication bus
- Corroded or loose bus connectors
- Low system voltage during module communication
- Water intrusion into a module or connector
How to fix U0073
- Scan all modules to find which have lost communication
- Check CAN bus wiring for shorts, opens, and terminal resistance
- Measure bus voltage and resistance at the diagnostic connector
- Isolate modules on the bus to identify the one causing the dropout
- Repair wiring or replace the failed module