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U0073 U0xxx · 网络通信（U） 高严重度
Control Module Communication Bus Off
A module has shut down its CAN transmitter, often as self-protection after persistent errors. It may be a symptom rather than the root cause.
严重程度说明： 高——立即停车诊断，继续行驶有扩大损坏的风险
你会注意到的故障现象
- Module unreachable
- Multiple warning lamps
- Functions unavailable
常见原因
按可能性从高到低排列——从最上面开始查。
- 1 Bus errors forcing the module off-line
- 2 Module supply voltage out of range
- 3 Internal fault
- 4 Software issue
如何排查
先做花钱最少、侵入最小的检查——大多数这类码不是零件问题。
- ✓ Check whether other modules are also off — if so, treat as a bus fault first.
- ✓ Verify power and earth at the silent module.
- ✓ Power-cycle the vehicle completely and rescan.
- ✓ Read any stored fault history that survives the shutdown.
维修方案
- Repair the underlying bus fault
- Restore the module supply
- Replace the module if it never recovers
U0073 —— 常见问题
Is the module dead? +
Not necessarily. Bus-off is a protective state. After fixing the bus, most modules come back on a power cycle.
Can I force it back? +
Some tools can issue a bus-off recovery command, but if the bus is still faulty it will drop out again.