Sök
U0251
System
Network (CAN Bus)
Scanner som krävs
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Lost Communication with Telematics Control Module

Understand U0251, common causes, and the right TOPDON scanner to diagnose it.

OnStar, connected car, or telematics module offline.

Vanliga symptom

  • Connected services unavailable
  • SOS button inop

Typiska orsaker

  • Failed telematics unit
  • Antenna fault
  • CAN wiring
  • Subscription not related — hardware comm fault

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 U0251 mean?
U0251 indicates lost communication with telematics control module. OnStar, connected car, or telematics module offline.
Can I diagnose U0251 with a basic code reader?
U0251 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 U0251?
Full-system scanner (engine, ABS, SRS, transmission, service resets) See recommended tools on this page.
Is it safe to drive with U0251?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.