Ok a little knowledge is dangerous and I have little knowledge of things electrical! But I think this is the correct wiring diagram item 8/120 is the egr valve. It looks as if 4candles is correct, the ecm does the controlling. Anyway I hope this helps.
wire diagram.jpg
The screen shot isn't very clear, from the top. The yellow wire goes to pin A66 of the ECM plug, green/white pin A71, green/grey doesn't go to the ecm, brown/black pin A28.