2003 Volkswagen TDI engine/malfunction indicator light is o

Two days ago the engine light starting coming on about one minute after I started up the car and remaining on the whole time the car was running. There were no strange noises and the car is driving fine. I took it to Autozone and they ran a diagnostic on it and go the code "P0670" which their computer said had to do with the glow plug control module and that it the probably cause was "poor electrical connection" or to "check control module for glow plug triggering." I called the VW dealer and he said as long as the engine light wasn't blinking, it wasn't a dire emergency which was good because I don't have the time to take my car there and be carless for days. Do you have any suggestions on ways I could check the electrical connections because maybe that's all it is.
Thank you
Mary