Check engine light came on this evening! Contacted OnStar and they said it was codes P0171 & P0174 - Fuel control system.....What could that be or what does that mean...? "Fuel control system"? Any help or ideas would be great! Truck only has 18,000 miles! Damnit! They also said I needed to get it to the dealer within 3 days and that hesitation and loss of power may be felt!?? Any ideas?? Thanks

 

Just saw the sticky with the codes! But what the hell is trim system too lean....what would cause this in a pretty much stock engine?

 

Did you run it out of gas?? Possibly an O2 sensor failed. One of mine went at 19,000mi.

Jim

 

No, never ran it out of gas...could any mods cause this besides FI...any simple bolt -on?? Thanks

 

You should be under warranty?. Most likley a vacumm leak.

 

Yeah I am, but just curious what it could be...one min. its fine and the very next check engine light is on.

 

how's your gas mileage? If it went to crap (assuming you don't have logging software) then you might have a leak like 1slow suggests. O2's see lots of air and keeps adding fuel to try to bring in what appears to be lean condition, when it's really not.
I do see superchips in your sig. Call superchips and ask them do they have many call backs for lean codes. They will ofcoruse argue you need to eliminate all mechanical possiblities. Put your stock tune back in. See if it goes away.

 

Put stock tune back in and stayed the asme....so I guess its a trip to the dealer...thanks guys

 

Do you have an O2 sensor after the flange where the headers connect to the exhaust? You might have a leak there.

 

Yeah I do...But I'll let the dealer handle from here. Runnin t the dealer 2-morrow