Code P0171

[cougarcat454]

2002 Bonneville SLE

Code says Fuel Trim System Lean Bank 1. Found a vacuum leak, thought it was probably throwing the code. I capped off the vacuum. Looks like a T coming off of the pcv. There was just a rotted piece of hose on the nipple and nothing else. I could not see where it might need to go if there was a vacuum hose going from it to another place, so I capped it. Had the code reset. Light has now come back on. I have not had it rescanned and am not sure if it will be the same code or not. This is the car my daughter drives, so not real sure how long it went before the light came back on.

My question is does any one know if the vacuum I capped should have a hose on it going someplace instead of being capped? This is on the back side of the engine, large hose you see goes in to what I believe is the pcv, which is in the back side of the back valve cover.
You can see the cap I put on, to the right side of the large vacuum hose.

Also if anyone else has had an experience with a P0171 code, what did you do to fix it?
Thanks.

[spoiledred94]

Get a vac hose diagram. Chilton's might have it or you may find one you trust online or get a professional Field Service Manual. There also may be a vac diagram on a label in your engine comapartment.

[redzmonte]

search for my post on my p0171 code.. found vac leak on the vac block (on top of blower), cleaned injectors (BG Fuel system cleaner), replaced vac harness by the TB, new fuel pump (was failing) and other things, my 171 code is not coming on anymore. most likely a vac leak but good to check other things to. my post has a bit of info that might help.

[00Beast]

The large hose should be going to the brake booster. The PCV is an enclosed system, no hoses on your car. That looks like it may run to the main vacuum harness, from the fuel pressure regulator up front? That would be my guess. Or the EVAP system.

[cougarcat454]

Yes, that is the power boost for the brakes. There is a small vacuum T coming off just ahead of the large hose. I checked and the fuel pressure regulator vac is there like it should be. I can not find any place for this to go to.
Would all 2002 be the same? Could someone just pop the hood on their car and see if they have this same hose out let in this location and if so, is it capped off or does it have a hose on it connected to something on the other end?

[redzmonte]

I dont have a NA motor so im sure mine is different. here is what a vac diagram says.. "To ACSRY".. your heater controls working correctly? the one of the SC motor lists one on the vac block as acsry and mine is capped from the factory.

[cougarcat454]

Yea, everything seems to work just fine. So not sure what that vacuum would need to go to.
Thanks for the diagram!

[redzmonte]

i dont have a car to compair it to but i don't think i goes to anything. it could be just a extra port for diagnostics. again my SC car also has the ACSRY port and its capped like this one:

[cougarcat454]

Ok. Tonight I decided to take the car and clean it up. On the drive to the car wash the check gas cap light came on the DIC. So maybe that is what is setting the ses light now instead of the original p0171 code. Will get it scanned tomorrow to see if it is the same code or different one. I filled it up with gas tonight after I got it all cleaned up and made sure the gas cap is secure. Can the check gas cap message on the DIC be reset or does it just take care of its self once the cap is secured properly?
Thanks again.

[cougarcat454]

Just scanned it again. The P0171 did not show up. So maybe the original uncapped vacuum took care of that problem.
P0440 and P0442 are showing up. Emissions evap problem of some type and like I said, the thing was saying to check the gas cap yesterday and today. So cleared the codes and will see if it comes back on. Sound like it could still be a leaky hose in the evap system or even the Evap canister purge solenoid.

My other thought is maybe the vacuum I capped off is suppose to be hooked into the evap system some how?

[steelmanwy]

I just went out and looked, there is a cap on that vacuum nipple on my non supercharged engine.

I dont have a NA motor so im sure mine is different. here is what a vac diagram says.. "To ACSRY".. your heater controls working correctly? the one of the SC motor lists one on the vac block as acsry and mine is capped from the factory.

To ACSRY might be left over from when the heater controls were vacuum actuated, but the '00+ are electrically actuated.

[cougarcat454]

I just went out and looked, there is a cap on that vacuum nipple on my non supercharged engine.

I dont have a NA motor so im sure mine is different. here is what a vac diagram says.. "To ACSRY".. your heater controls working correctly? the one of the SC motor lists one on the vac block as acsry and mine is capped from the factory.

To ACSRY might be left over from when the heater controls were vacuum actuated, but the '00+ are electrically actuated.

Thanks for taking a minute to go take a look. It probably does just need to be capped off like it is.
I appreciate the post.

[spoiledred94]

To ACSRY might be left over from when the heater controls were vacuum actuated, but the '00+ are electrically actuated.

Thanks for taking a minute to go take a look. It probably does just need to be capped off like it is.
I appreciate the post.

I think it's a good idea. I just don't know


EDIT:


Hey well check out this current Pontiac Bonneville Club thread.Summer Issues by "FranksDad"
They are looking into that same vac port issue