The U2013 fault code is a manufacturer-specific code used to identify different faults. For example, in Ford vehicles, it shows that there is no response from the Compass Module.
All vehicle controllers maintain continuous communication through the Serial Communication Protocol (SCP) bus network, which is also known as the J1850 bus, or the CAN (Control Area Network) bus network. Therefore, these communication systems are exposed to any kind of failure. If there is an intermittent connection between the controllers, the communication stops.
The manufacturer Ford sets the DTC U2013 OBDII code when other modules fail to communicate with the Compass Module via the CAN bus network.