The thermo fans are working good

I had the same problem with an EL 6, had the auto checked and serviced, checked all plugs etc etc like you have done and it still wouldnt change. It had the mechanic stumped too as the diagnostics was showing no problems either. Sorry to say but you might be up for a battle with this one. Pisses you off too hey. The only thing I didnt do or check was to flush the cooling system and see if that fixed it i.e blockage in the trans cooler overheating the auto.

Well at this stage I am going to check the wiring loom to see if that is ok