No communication

Okay I went through every fuse in the car, none are blown

I did find a location under the hood that says ecm batt 10Amp but there is no fuse there (it is location 51). It only has gold connectors only on one side of where the blades plug in, so it looks like just a spare socket. Just weird because all the other locations like that say not used.

The car is just running real sluggish since the check enigine light has come on and now I cannot read the codes. Any more advice would be great. THANKS

Thanks. Yes I checked this fuse panel yesterday also. All my fuses were good. My data link connector under the steering wheels only has 6 wires can you send me a diagram of what voltage or routing these wires should go to so I can check for open circuits. If you think I need to go a different route, just let me know. Thanks for helping me. Still kinda confused if the data link connector is for the ECM or BCM

Thanks man, you are great. Yeah I tried several and even took to the dealership and theirs would not work. They want to charge me by the hour to now trouble shoot the electrical system. I got under there yesterday and look at the data link connector and it only has 6 wires, does that sound right?

When I get home today I guess I will check these wires, what voltage should I be looking for on the red (prob. Just 12 volts)

Thinking maybe should I check the large locking connectors on BCM

Man thanks so much, I will try it when I get home

This is a 2008 4 cyl, so I am not sure if that makes a difference. I swore I saw a green wire in the harness but not for sure. I will try it when I get home

Hey Doc
I checked the red wire 12 volts strong at that point and both grounds are perfect. There is a green wire, would you please look up that for me (location termination). Also on the BCM terminals I did not see any numbers, how is the numbering scheme for this terminal block (left to right?) Thanks a million

I checked the tan wires (2 of them)and a green wire from Data link to the bcm panel (see pic). No continuity on them no matter what I did. I had voltage on red pin and ground on both blacks. Do these tan and green wires go straight to BCM or should I look for a connector along the way

I took the J2 blue connector off of the BCM (see example pic) and pinned it out and I have continuity straight from the data link to that connector, so it is getting signal. At this point Do you think replacing the bcm is even an option

I wish I knew if it was just a sensor to replace causing this sluggish acceleration because that is all that is wrong with the car since the check engine light came on and I would take a chance and replace something minor, if I could find out what commonly goes bad on the G6 at around 60,0000 miles

If I buy another bcm does it have to be flashed for my car or is it just plug and play. I guess I need to make sure it is the exact same GM part #? (See pic) I appreciate it so much and even though I am still so frustrated over this car, you have helped keep me calm.I also did the battery trick last week and it still ran crappy but the light stayed off for two days then came back on

I got some different news! I worked all weekend, checking this and that. I found the female pin of the red wire on the data link plug looked bent up inside where it would not make a conncetion with the male scanner plug. So I bent it down where it would make a connection, drove back to the same autoparts store, same scanner and it linked up first time and read the car! The only problem is the dealership cleared the check engine light last week so the scanner says "no check engine light detected" "more drive cycles required. So now hopefully the light will come back on, not sure how they cleared it but everytime I cleared it with the battery trick it would come back on in 2 to 3 days. Let me know what you think about this new revelation

I honestly prayed before plugging in the scanner this morning :) Here is what code I have: P4020 - Catalyst System Efficiency Below Threshold (Bank 1).