Disco 4 (LR4) Discovery4 OBD temperature error

Hi All. My 2010 Discovery4 hse has developed this fault for no reason has anyone any ideas. When entering the vehicle the OBD lights up and within seconds a temperature error warning comes on the screen and almost immediately turns off. So no radio or sat nav. Sometimes very rarely it will come on and stay on for a while but no reverse camera. Checked all fuses, battery and inspected wiring with no faults on camera or anything else found.