Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2019 Ford Expedition, 2018 Lincoln MKZ, 2018 Ford Transit-350 HD, 2018 Ford Transit-350, and 2018 Ford Transit-250. However, it is still accessible from the selected car via links, so may be relevant.
DTC U0121:00 indicates a possible failure of the HS-CAN which can be due to a circuit fault in the HS-CAN, the PSCM wiring harness or an ABS module concern.
Do not install a new PSCM as part of the repair for a PSCM DTC U0121:00.
The presence of DTC U0121:00 prevents the active park assist system (if equipped) and the lane keep assist function (if equipped) from activating. If set during an active park assist event, the event is terminated and the active park assist system is deactivated.