Volvo Repair: P1618 OBD II Code, obd ii code, faulty connections

Question
I am getting this code on the OBD reader, and clearing it just makes it come up again right away.  I found on another website that this code means "Fault in Lead Between AW 50-52 and Motronic 4.3 (MIL Requested)".  Is this right?  If so, what does it mean and what do I need to do/replace to fix it?
Thanks, I appreciate your time
Jeff

Answer
You may have a faulty gear selector switch (very common) but I have gone round on that code before.I have found faulty connections in the wiring harness that took long hours to locate.You may want to bring this one in and have it checked at the dealer. Any other codes? Also check for alternator output, have seen alot of difficult problems go back to a overcharging alternator.Which code was it though?