U0121
Système
Network (CAN Bus)
Scanner requis
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Lost Communication with ABS Control Module

Understand U0121, common causes, and the right FOXWELL scanner to diagnose it.

ABS module not communicating — ABS, stability control, and sometimes cruise may be disabled.

Symptômes courants

  • ABS light on
  • Traction control off
  • C-codes may accompany

Causes typiques

  • ABS module failure
  • Wheel speed sensor wiring damaging comm
  • Low voltage
  • Blown ABS fuse

Quel scanner choisir ?

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

Utilisez les données en direct et le freeze frame avant de remplacer des pièces. Les codes ABS, SRS et U nécessitent souvent un scanner mult systèmes.

Conseils de diagnostic

  • Enregistrez le freeze frame lors de la première apparition du code
  • Effacez le code uniquement après avoir corrigé la cause
  • Vérifiez les codes en attente associés
  • Vérifiez que la batterie est au-dessus de 12,4 V avant de suspecter un capteur

Scanners FOXWELL recommandés

Questions fréquentes

Can I diagnose U0121 with a basic code reader?
U0121 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with U0121?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.