Hey guys, it’* Aaron again… so a little update to the 03 envoy I’ve been working on. I got her back up and running by purchasing a transmission from a salvage yard. Ended up having to replace that throttle body because it turns out it was going bad according to the OBD-2 reader I used. However, I’ve recently come up on another issue that I can’t quite figure out this time. I have a feeling it could be something minor but I need to make sure. So the engine light came back on eventually after stalling a few times at a complete stop, and I got 2 different codes that apparently tie in with each other. The first was a “U1064” stating “Lost Communication With Body Control Module” and the second one was a “U1016” stating “Lost Communication With Powertrain Control Module”. The internet said simple stuff like checking the spark plugs for spark and checking the gas cap blah blah blah. But I’ve already changed the plugs and ignition coils. I’m starting to believe I have a fuel delivery issue…. The first things on my list are fuel pressure regulator and fuel injectors. I don’t suspect my fuel pump because I’ve been told that it would make a significant difference if it was. I’ve recently changed the fuel filter as well. Any opinions on this?

Using the internet for professional help is almost certain to get the most incompetent answers. You have a comm issue. You need to check the network. Total network resistance is the place to start. Should be 60 ohms. BCM may be having issues.

see, funny enough earlier this evening around 7 pm, I went ahead and bought a “fuel pressure regulator” and some seafoam to dump in the tank… I erased the codes and I ran it for a while afterwards and rescanned it when I was finished. No codes came up… maybe I dodged a bullet with this one… I’m not sure, I’m still having a bit of lag when stepping on the gas, but maybe it’* the new transmission and needs to be flashed. But I will definitely look into getting the control modules checked out.

Remember when I said that the check engine light went away? Well not exactly. It’* gone but it flashes when I’m driving and gaining speed to make the transmission shift into the next gear. Now I’ve read somewhere before that there is something that tells the transmission when to shift. I forgot the name of it but I’m wondering if that’* my hard shifting issue.

If the engine doesn't run right the trans isn't going to work right. look into the cause of the ses light. with the ses light flashing on accel I would suspect an engine misfire issue.

see that’* just it, I’ve already run the scans twice. Once after a hour drive, and another while driving. The things says no codes as previously before I replaced the fuel pressure regulator, there were “multiple or random misfires” but now none. I can try to see if I’m getting spark in all 6 cylinders. But if I am, what else could I be looking at?

What is the fuel pressure with key on engine stopped?

What is the fuel pressure with engine at idle?

I’m not exactly sure, I don’t own the pressure gauge for that but when I replaced the regulator, the pressure was pretty high being as though it sprayed gas all over my arm.

As the old saying goes, "No such thing as a mechanic in a bottle".

Time to get a fuel pressure gauge. 1PSI will spray all over your arm. 50PSI will spray all over your arm.