Accepted Answer

the communications codes may be just a blip in the system between his scan tool and the vehicles computers.I have seen this low rail pressure before,in most cases its the fuel filter that is plugged and needs replaced but it sounds like your on top of that.If you have a leak in the fuel lines between the fuel tank and the fuel filter or anywhere else in the system this can cause this problem as you would be pumpng to prime but would be just sucking air,one common leak i have found is the fuel filter bleed screw and the hoses going to the fuel filter and from the filter to the pump,you may have to inspect all of these hoses and have someone pump the primer to see if you can locate a leak,if no leaks are found then you may have a bad fuel filter housing,this housing comes with a new pump,i have had to replace some of these before on these vehicles and alot of other guys i work with as well have replaced these.Here are some suggestions to check over.also check your engine oil level and make sure its not overfull as an injector may be bleeding this pressure down into the crankcase,these usually fail around every 70000 miles.I hope this helped,if you need anything else let me know,Thanks Pete

Expert:	Pete
Pos. Feedback:	99.0 %
Accepts:
Answered:	10/1/2009

ASE Certified Technician

12 years GM diagnostic Technician/Mercedes Benz Technician