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U0073
System
Network (CAN Bus)
Scanner som krävs
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Control Module Communication Bus Off

Understand U0073, common causes, and the right TOPDON scanner to diagnose it.

The CAN bus is offline — no module communication. Often wiring, termination, or a module shorting the bus.

Vanliga symptom

  • Multiple warning lights
  • No-start
  • Gauges dead
  • Many U-codes at once

Typiska orsaker

  • CAN wiring damage
  • Failed module pulling bus down
  • Corrosion in DLC or junction connectors
  • Aftermarket device on OBD port

Vilken scanner behöver du?

Full-system scanner (engine, ABS, SRS, transmission, service resets)

Använd live-data och freeze frame innan du byter delar. ABS-, SRS- och U-koder kräver oftast en fullsystems-scanner.

Diagnostiktips

  • Spara freeze frame när koden först sätts
  • Rensa koden först efter att orsaken är åtgärdad
  • Kontrollera relaterade väntande koder
  • Verifiera batterispänning över 12,4 V innan du misstänker sensorer

Rekommenderade TOPDON-scannrar

Vanliga frågor

What does U0073 mean?
U0073 indicates control module communication bus off. The CAN bus is offline — no module communication. Often wiring, termination, or a module shorting the bus.
Can I diagnose U0073 with a basic code reader?
U0073 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Which TOPDON scanner do I need for U0073?
Full-system scanner (engine, ABS, SRS, transmission, service resets) See recommended tools on this page.
Is it safe to drive with U0073?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.