PO171 code
Drifting
Joined: May 2010
Posts: 1,274
Likes: 75
From: Fairfield County, CT
I use to get it frequently on my C6 after it was tuned. After checking several things, found out car was tuned only @ WOT. After 50 - 100 miles of non-WOT, it would return. As this does not appear to be your issue, I found this:
Common Problems That Trigger the P0171 and P0174 Code:
PCM software needs to be updated
Vacuum leaks (Intake Manifold Gaskets, vacuum hoses, PCV hoses, etc.)
Mass Airflow Sensor (MAF)
Plugged Fuel Filter or weak Fuel Pump
Plugged or dirty Fuel Injectors
I suggest you start @ the top of list and work your way down.
Good luck.
Common Problems That Trigger the P0171 and P0174 Code:
PCM software needs to be updated
Vacuum leaks (Intake Manifold Gaskets, vacuum hoses, PCV hoses, etc.)
Mass Airflow Sensor (MAF)
Plugged Fuel Filter or weak Fuel Pump
Plugged or dirty Fuel Injectors
I suggest you start @ the top of list and work your way down.
Good luck.
Thread Starter
Advanced
Joined: Aug 2009
Posts: 53
Likes: 1
P0171
Thanks for the reply. I have checked all of the items with the exception of the upgrade. It is going back to the dealer tomorrow. The AFE air box is of course advertised as a no tune add-on. If it indeed flows more air as they claim, my first thought would be that is causing a lean code. I would have thought that the factory tune would compensate for that though. I will relay the results when I get them.
Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
Generally on a V8 like the LT's that share a common intake tract the banks run lean or rich together (within a few points of each other) if there is a problem with the intake.
So if you continue to drive it, it would be normal for the 174 lean code to pop up as well.
If the right bank (174) doesn't run lean then its likely you have a problem related specifically to the left bank.
I say this because it is possible the new intake caused this. But if it in fact did both banks will likely go lean if you continue to drive the car.
This will indicate to you if the intake is to blame or not.
A data log would tell you this without waiting for the 174 code to pop.
Thread Starter
Advanced
Joined: Aug 2009
Posts: 53
Likes: 1
Po171
The car is at the dealer for their opinion. It was scheduled to go in to fix the passenger side seat cooler. The check engine light didnt come on until 2500 miles after the AFE box was installed. It didnt come back on for a couple of days then has been on steady since. I cleared the code with my scanner but came on after second start.
Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
The car is at the dealer for their opinion. It was scheduled to go in to fix the passenger side seat cooler. The check engine light didnt come on until 2500 miles after the AFE box was installed. It didnt come back on for a couple of days then has been on steady since. I cleared the code with my scanner but came on after second start.
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Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
The car is at the dealer for their opinion. It was scheduled to go in to fix the passenger side seat cooler. The check engine light didnt come on until 2500 miles after the AFE box was installed. It didnt come back on for a couple of days then has been on steady since. I cleared the code with my scanner but came on after second start.
2. The "didn't come back on for a couple of days" then has been on steady since. Could indicate the condition was beginning. A clamp or something slowly working lose (the intermittent period) until it was so loose the issue became "steady".
3. The CEL coming back on shortly/quickly after you reset it tells you the condition is definitely there (constant) and it is significant enough the computer picks it up right away.
I know you checked for vacuum leaks and loose clamps.
FYI
Twice over the years I have had this issue with CAI's.
Drove me crazy. They both looked normal while inspecting the car at idle or when it wasn't running. However when the engine was under load and sucking air they would collapse and form a gap at a connecting joint. Then when the engine went back to idle or off the CAI would go back to its original form and the problem would be virtually undetectable by the naked eye. This condition set both the 171 and the 174 codes in my case. I readjusted the clamps and the rubber couplings and the issue was resolved.
Burning Brakes
Joined: Jan 2009
Posts: 1,176
Likes: 69
From: Long Island NY
The car is at the dealer for their opinion. It was scheduled to go in to fix the passenger side seat cooler. The check engine light didnt come on until 2500 miles after the AFE box was installed. It didnt come back on for a couple of days then has been on steady since. I cleared the code with my scanner but came on after second start.
Burning Brakes
Joined: Jan 2009
Posts: 1,176
Likes: 69
From: Long Island NY
Mine went on with a intake on, then put stock intake back on and got updates but soon after the light came back on for same exact code. Bank 1 sensor 1 o2 sensor... Just trying to avoid another trip to dealer.