Engine light warning broken wire help please

[ShaunB]

I think I may have done something bad ,I was pulling wires through from underbonnet to glove box area with a coathanger and got it snagged when I finally got it out it came with broken dark green/black wire I've connected this back together but now I have engine fault light on,have I just upset it by cutting and joining this wire or have I broke another wire where I can't see it .where does the green and black wire go to from the ecu ? .Car is 2003 cdti and everything seems to be as it was apart from the warning light .Any advice would be greatly appreciated .