I have a 2008 chevy suburban, last week reduced engine power showed up. I scan the truck and I got code P0641. there is no other codes. so I went to start the truck an it started for about 1 min. then it shut off on its own. and now it wont start back up. I replace the FSCM, I got it from GM FLASH. but its still not starting, I don't hear the fuel pump coming on.

 

Did you check the FSCM fuse in the panel in your engine compartment?

 

Yes, and they where good...

 

Good visually or did you check it with a meter or light? If it was visual just slap a known good one in there. If it doesn't fire the pump up and you already changed out the FSCM then it's most likely the pump. I replaced my pump from the top. I cut a hole out under the seat. I have yet to edit the "DIY" video for youtube.

 

Yes, I check both ways. But I will change it out. And see what I get....

 

Good luck!!

 

No luck with wiring check?

 

I'm cautious suspecting the pump since there are so many variables in that circuit to make it power up. But it's leaning that way...... I assume it's a 2007 to 2014?

 

Yea,641 is 5v reference,with cam sensor involved,pump is 12v, different circuit,that sparky's answers.com is the solve to the problem,might not be exact in the fault area,but it's all there,wiring colors and sensors affected

 

Well, no luck yet. I been going thru the wires. Trying to find something wrong, No luck. But I'm about to change the camshaft sensor, to see if it will make a difference. And i'm going to check out answers.com too. To see what info I get from there. And thanks for the help.