A control module has detected that the communication bus is non-functional and has shut its bus interface off. Affects multiple modules at once because none can communicate; on most vehicles the dashboard lights up with several warning lamps simultaneously.
High severity. Can I keep driving?Do not keep driving if there are several warning lights or the car is running poorly: important systems can fail suddenly. If it only appears as a stored code and the car is running normally, go straight to get it checked.
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Most likely causes
- CAN line shorted to supply or ground
- Terminating resistor failed
- One failing module pulling the bus down
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
What each character of U0073 means
- U: Communication network
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- 73: Specific fault in that system
Frequently asked questions
Can I keep driving with code U0073?
Do not keep driving if there are several warning lights or the car is running poorly: important systems can fail suddenly. If it only appears as a stored code and the car is running normally, go straight to get it checked.
What causes code U0073?
The most common causes are: cAN line shorted to supply or ground; terminating resistor failed; one failing module pulling the bus down.
Related codes
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.