One method that sometimes works with spurious error codes is to reboot the radio by (i) firstly make sure you have the security code (ii) remove fuse or battery connection and leave disconnected for 5 minutes (iii) replace fuse or battery connection
RegWorts, April 2008
Hi Elizabeth, error code E11 from the "Ford manual" is "SPI bus failure" actions to fix, check the wiring harness if ok replace radio!!
