DTC U0001 High Speed CAN Communications Bus: Description

WARNING: This page is about a different car, the 2017 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

The PSCM monitors the HS-CAN messages when the ignition has been on for more than 5 seconds, when the voltage to the PSCM is greater than 6.5 volts and there are no DTCs present inhibiting PSCM operation.

DTC U0001:88 (High Speed CAN Communication Bus: Bus Off) - This DTC sets if the PSCM detects transmission of HS-CAN messages is not acknowledged by other modules or if the HS-CAN is deemed to have a communication error for greater than 5 seconds.