HELP! Tried to flash my N54 DME with MHD and the process got interrupted (laptop battery died). Now the car wont start at all. Dashboard lights come on but engine doesnt crank.
Did I brick the ECU? Is there a way to recover it? Im panicking right now.
Edit: car is 2010 E90 335i
Dont panic. In most cases the ECU isnt actually bricked - the flash just didnt complete properly. Try these steps: 1) Disconnect the battery for 30 minutes. 2) Reconnect and try to flash the stock file back. 3) If the car cranks but wont start, the ECU is alive - it just has a bad map. 4) If theres zero response (no dash lights, no crank), check the OBD fuse first.\n\nWhat tool did you use for flashing? And what engine/ECU type?
This happened to me once with a Bosch MEVD17.2 ECU. The issue was the battery voltage dropped during flashing. Always use a battery charger during ECU flashing - the process draws a lot of power and if voltage drops below 12V mid-flash, it can corrupt the data. I recovered mine by bench-flashing with a BDM adapter.
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