TORQDEX // POWERTRAIN DTC
Control Module Communication Bus A Off
A control module has detected that communication bus A is not operating normally.
00 // CODE DEFINITION
What U0073 means
U0073 indicates that a primary module communication network has gone offline or cannot communicate normally.
A shorted network, failed module, wiring fault, poor power supply, ground problem, or connector issue may be responsible.
01 // COMMON SYMPTOMS
What you may notice
02 // COMMON CAUSES
What can trigger U0073?
Communication bus short
CAN wiring may be shorted together, to ground, or to voltage.
Failed network module
A module can electrically pull the communication bus offline.
Open or damaged network circuit
Harness or connector damage can interrupt network communication.
03 // DRIVEABILITY
Can I keep driving with U0073?
Use caution. A high-severity fault can affect engine, transmission, electrical, or emissions-system operation. If the vehicle is running poorly, overheating, losing oil pressure, flashing the check-engine light, or entering reduced-power mode, avoid continued driving until the cause is diagnosed.
04 // DIAGNOSTIC ORDER
Start here
Scan the complete vehicle
Record all communication and network codes before disconnecting modules.
Check battery and charging voltage
Verify system voltage is stable.
Inspect network wiring
Check CAN wiring and connectors for damage, corrosion, or aftermarket modifications.
Isolate the network fault
Disconnect branches or modules methodically when necessary to restore communication.
05 // COMMON REPAIR AREAS
Systems commonly involved
These are common areas associated with U0073. Testing should confirm the actual fault before parts are replaced.
Communication bus short
CAN wiring may be shorted together, to ground, or to voltage.
Failed network module
A module can electrically pull the communication bus offline.
Open or damaged network circuit
Harness or connector damage can interrupt network communication.
06 // DIAGNOSTIC PRINCIPLE
Confirm the fault before replacing parts
U0073 identifies a condition detected by the vehicle control system. It does not automatically identify one failed component. Test the affected system before replacing parts.
07 // RELATED TORQDEX DIAGNOSTICS
Related diagnostic guides
Continue troubleshooting by symptom and system. These TorqDex guides cover common diagnostic paths associated with this trouble code.
08 // RELATED CODES