Check engine light comes on when ignition is switched on. I await the glow plug light to go out, before starting and by this time engine check light has normally gone out also.
Sometimes the enginer check light does not go out.
If you then drive (in safe mode) await normal running temperature. Stop. Turn off, and re-start, then normal service is resumed.
It appears to do this more in Cold Damp conditions, rather than cold dry conditions.