U0073 — Control Module Communication Bus A Off
| Meaning | The engine computer has lost communication with the main data network in the car. This network is the wiring system that different computers use to talk to each other, meaning modules can no longer share important operating data. |
| Family | Network (U) |
Typical symptoms
Various gauges or instruments stopping to work
Car may fail to start or experience erratic system behavior
Common causes
Damaged or pinched wires along the communication network
A faulty control module that is pulling down the communication line
What to do
Frequently asked questions
What does code U0073 mean?
Control Module Communication Bus A Off. The engine computer has lost communication with the main data network in the car. This network is the wiring system that different computers use to talk to each other, meaning modules can no longer share important operating data.
Can I keep driving with code U0073 active?
With caution: limp mode possible, have it checked soon
Common causes — U0073
Poor or corroded connection at the data network wiring harness plug Damaged or pinched wires along the communication network A faulty control module that is pulling down the communication line
How do you fix code U0073?
You should check the main battery and charging system first, as low voltage often causes communication dropouts. This is an urgent issue because the car may become completely undrivable if the main computers stop talking entirely.
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Contact usRelated codes
- U0001 — High Speed CAN Communication Bus
- U0002 — High Speed CAN Communication Bus Performance
- U0003 — High Speed CAN Communication Bus (+) Open
- U0004 — High Speed CAN Communication Bus (+) Low
- U0005 — High Speed CAN Communication Bus (+) High
- U0006 — High Speed CAN Communication Bus (–) Open
- U0007 — High Speed CAN Communication Bus (–) Low
- U0008 — High Speed CAN Communication Bus (–) High
- U0009 — High Speed CAN Communication Bus (–) shorted to Bus (+)
- U0010 — Medium Speed CAN Communication Bus
- U0011 — Medium Speed CAN Communication Bus Performance
- U0012 — Medium Speed CAN Communication Bus (+) Open