Cold Starting

[Phocks]

I have a 54 plate 1.5DCi and have the dreaded service light and check injection.
The only problem that this seems to give is to cold starting; when warm the car runs well. I have checked the voltage and continuity through the glow plugs and the power to the Glow plugs and all seem normal, as soon as it fires up all seems well.
The service light initially came on when the engine was warm.