'11 135i N55 - Error 3490 'Map Thermostat, Control: Line Interruption' remains after replacing thermostat + pump
I was getting the error 3490, which BimmerLink translates as 'map thermostat, control: line interruption' and really didn't have any problems except that it seemed to run the fan all the time and the car was slower to warm up.
The diagnostic seemed to be that the thermostat was bad, which was plausible, the thermostat and water pump had about 50,000 miles on them, so I just replaced both of them.
However, my Error 3490 is back with the new thermostat, so what's my next step in figuring out why there's a control line interruption? If the connector's definitely secure, how likely is it that the problem is somewhere either in the wiring from the connector to the DME or (please god no) in the DME itself?