DTC U0121: Lost Communication with the Anti-lock Brake System (ABS) Control Module: Action
WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
CARRY OUT an ABS module self-test. If the diagnostic scan tool indicates the module is not responding, REFER to MODULE COMMUNICATIONS NETWORK to DIAGNOSE the network communication concern. If ABS module DTCs are present, REFER to ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL to DIAGNOSE the ABS system fault.