Hello all. First time caller, long time listener. I have an 1997 A4 1.9 TDi (110) with a fault code (from VAG-COM) I do not understand. In full - 00550-Start of injection regulation 17-10- Control difference intermittent. Does anybody know what this means and what causes it. The heater coil light comes on and stays on after driving a while (sometimes after a few seconds, sometimes after a few minutes). Hope someone can help.