So she has done it again, she used to fail to power up the ECU last year when it was cold sometimes, so i replaced the ECU relay and all seemd well. Well today the temp dropped to a shade over 5 Degress and the ECU wouln'dt power up. Ie no MIL light and EPC light stuck on. After a while of sitting and turning the ignition on and off/waiting, the light popped on and she went straight away. Any ideas? 2001 A3 TQS ARY Engine. The problem is it wont happen again for a while so tracing it is impossible, grrr.