DTC U0121: Lost Communication with the Anti-lock Brake System (ABS) Control Module: Description

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The PSCM will monitor the HS-CAN bus when the ignition has been on for more than 5 seconds, when the voltage to the PSCM is greater than 9 volts and when there are no DTCs present that are inhibiting PSCM operation.

DTC U0121:00 (Lost Communication with the Anti-lock Brake System (ABS) Control Module: No Sub Type Information) - This DTC will set when communication between the PSCM and the ABS fails. The ABS sends a steering angle sensor message to the PSCM. If this message is missing for more than 32 milliseconds and the PSCM has not set DTC U0001:88, then the PSCM will set U0121:00.