Parts
$0-600+
U0073 — Control Module Communication Bus Off
CAUTIONIs it safe to drive? A communication bus has gone offline — modules can't talk. Multiple systems may be affected; identify the bus and failed node before driving further.
What U0073 means
U0073 means a CAN bus entered a 'bus-off' state, usually because of error frames from a module with an electrical fault or because the bus wiring is shorted. One faulty module or wiring short can take an entire network down.
Most likely causes (in order)
- Short or open in the CAN bus wiring
- Failed module continuously generating error frames
- Corroded connector or damaged CAN wiring
- Lost power or ground to a module on the bus
Symptoms you might notice
- Several warning lights at once
- Modules reading as not present
- Communication codes across multiple systems
What to check first
Measure CAN-H to CAN-L resistance with key off. If it's not ~60 ohms, you have a wiring issue. Unplug modules one at a time to find the one dragging the bus into error frames.
Repair cost & difficulty
Labor
1-10+ hr
Difficulty
DIY-friendly