P0174 code I have a thought.
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
P0174 code I have a thought.
I was really low on gas. Drove a mile or so, light on. Had my scanner with me and code read P0174 " bank 2 system lean". Could low fuel cause that?
Thanks
Thanks
Drifting
Joined: May 2010
Posts: 1,274
Likes: 75
From: Fairfield County, CT
I have had this code in my 2010 A6 GS. For me the issue was the tune. It was tuned just for WOT and ran lean when cruising for any length of time. I noticed no change in performance but needed fuel to be added at lower RPM to make it go away. Here some info I found while researching it.
Symptoms
Check Engine Light will illuminate
In some cases, no adverse conditions may be noticed by the driver
In other cases, there may be performance problems, such as a lack of power on acceleration and some "coughing" or misfiring
The vehicle may have trouble idling, especially when warm or when sitting at a stoplight
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
Common Misdiagnosis
Oxygen Sensors
Polluting Gases Expelled
Symptoms
Check Engine Light will illuminate
In some cases, no adverse conditions may be noticed by the driver
In other cases, there may be performance problems, such as a lack of power on acceleration and some "coughing" or misfiring
The vehicle may have trouble idling, especially when warm or when sitting at a stoplight
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
Common Misdiagnosis
Oxygen Sensors
Polluting Gases Expelled
Former Vendor
Joined: Oct 2006
Posts: 278
Likes: 17
From: Auburn/Dacula/Lawrenceville Georgia
The best thing to do when you have a possible vacuum leak issue is to have someone scan the car and watch fuel trims. If you are dealing with a real vacuum leak, your trims will spike due to un-metered air entering the engine after the MAF. This will usually confirm a leak.
If the trims stay within +/- 5%, it's still possible to have a very small leak but it'll be something you'll have to search for. Check in the intake tract behind the MAF to make sure air isn't creeping in somewhere, throttle body gasket, booster hose, to name a few.
Something that's happened to me one time before and it literally kicked my butt until I found it, was a weak fuel injector on a 2009 Z06. This was an isolated incident however so I wouldn't start looking at the injectors until all other options have been exhausted.
I think the first step to prevent chasing your tail is to have the car scanned. Good luck OP!
If the trims stay within +/- 5%, it's still possible to have a very small leak but it'll be something you'll have to search for. Check in the intake tract behind the MAF to make sure air isn't creeping in somewhere, throttle body gasket, booster hose, to name a few.
Something that's happened to me one time before and it literally kicked my butt until I found it, was a weak fuel injector on a 2009 Z06. This was an isolated incident however so I wouldn't start looking at the injectors until all other options have been exhausted.
I think the first step to prevent chasing your tail is to have the car scanned. Good luck OP!
Last edited by Josh@SpartanLSX; Sep 11, 2013 at 08:27 AM.
Drifting
Joined: May 2010
Posts: 1,274
Likes: 75
From: Fairfield County, CT
Something that's happened to me one time before and it literally kicked my butt until I found it, was a weak fuel injector on a 2009 Z06. This was an isolated incident however so I wouldn't start looking at the injectors until all other options have been exhausted.
I think the first step to prevent chasing your tail is to have the car scanned. Good luck OP!
I think the first step to prevent chasing your tail is to have the car scanned. Good luck OP!
Interesting. In my car, a bent pin on a fuel injector was the cause of a P219A code. What a PITA to diagnose. Did all sorts of things before I found it. Smoked the engine, switched O2 sensors from side to side, had a cylinder leak down test, etc.
Drifting
Joined: May 2010
Posts: 1,274
Likes: 75
From: Fairfield County, CT
It could be as simple as a dirty MAF. Get some MAF cleaner spray 1st. Costs < $8 and only takes 15 minutes. If it comes back after a while then move on to the tune, a leak, the fuel injectors...
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Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
The best thing to do when you have a possible vacuum leak issue is to have someone scan the car and watch fuel trims. If you are dealing with a real vacuum leak, your trims will spike due to un-metered air entering the engine after the MAF. This will usually confirm a leak.
If the trims stay within +/- 5%, it's still possible to have a very small leak but it'll be something you'll have to search for. Check in the intake tract behind the MAF to make sure air isn't creeping in somewhere, throttle body gasket, booster hose, to name a few.
Something that's happened to me one time before and it literally kicked my butt until I found it, was a weak fuel injector on a 2009 Z06. This was an isolated incident however so I wouldn't start looking at the injectors until all other options have been exhausted.
I think the first step to prevent chasing your tail is to have the car scanned. Good luck OP!
If the trims stay within +/- 5%, it's still possible to have a very small leak but it'll be something you'll have to search for. Check in the intake tract behind the MAF to make sure air isn't creeping in somewhere, throttle body gasket, booster hose, to name a few.
Something that's happened to me one time before and it literally kicked my butt until I found it, was a weak fuel injector on a 2009 Z06. This was an isolated incident however so I wouldn't start looking at the injectors until all other options have been exhausted.
I think the first step to prevent chasing your tail is to have the car scanned. Good luck OP!
St ftrm1(%). -0.8 to 2.3
LT ftrm1. 8.6 to 10.2
St ftrm2. -2.3 to 4.7
LT ftrm2. 4.7
I don't know what these numbers mean, maybe someone could help. I realize it could mean nothing. Help guys.
David
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I have a scanner, actron 9500. I looked at SFTR and LFTR . By memory it was like
St ftrm1(%). -0.8 to 2.3
LT ftrm1. 8.6 to 10.2
St ftrm2. -2.3 to 4.7
LT ftrm2. 4.7
I don't know what these numbers mean, maybe someone could help. I realize it could mean nothing. Help guys.
David
St ftrm1(%). -0.8 to 2.3
LT ftrm1. 8.6 to 10.2
St ftrm2. -2.3 to 4.7
LT ftrm2. 4.7
I don't know what these numbers mean, maybe someone could help. I realize it could mean nothing. Help guys.
David
The car can only correct fueling errors of 25% or less - if the errors are more than that a CEL will be set. In your case, if the car is reading > 25% lean, that normally means unmetered air is getting into the engine, most normally due to a vacuum leak.
You fuel trims posted above would not set a CEL - you'd see them +-25% for that.
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
Those figures are the % error compared to a specified fuel map. The car is adding fuel (positive) or taking out fuel (negative) to maintain stoichiometric during closed loop operation. ST is short term fuel trims, LT is long term, a summation of short terms. The O2 sensors monitor for stoichiometric during closed loop operation (warm engine and not WOT) and the computer uses their report of actual air/fuel ratio compared to lambda to adjust the fueling of the car. The car tries to maintain 14.7 a/f ratio for gasoline.
The car can only correct fueling errors of 25% or less - if the errors are more than that a CEL will be set. In your case, if the car is reading > 25% lean, that normally means unmetered air is getting into the engine, most normally due to a vacuum leak.
You fuel trims posted above would not set a CEL - you'd see them +-25% for that.
The car can only correct fueling errors of 25% or less - if the errors are more than that a CEL will be set. In your case, if the car is reading > 25% lean, that normally means unmetered air is getting into the engine, most normally due to a vacuum leak.
You fuel trims posted above would not set a CEL - you'd see them +-25% for that.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
It takes a pretty big hole to cause a p0174 code...most likely is your air bridge may have come loose from your throttle body or your maf is loose. The valley to intake pcv hose is on the passenger side near the front of the intake.
Did you clean your maf?
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
If those are your recent lifts those are fine and won't set a cel.
It takes a pretty big hole to cause a p0174 code...most likely is your air bridge may have come loose from your throttle body or your maf is loose. The valley to intake pcv hose is on the passenger side near the front of the intake.
Did you clean your maf?
It takes a pretty big hole to cause a p0174 code...most likely is your air bridge may have come loose from your throttle body or your maf is loose. The valley to intake pcv hose is on the passenger side near the front of the intake.
Did you clean your maf?
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
I just tightened 90% of the screws that hold the intake down. 1/16 to 1/4 of a turn. Did I fix my problem? I will go for a short ride. I did get bucking in 1/2 gear. I said to myself, I don't have a cam. What is this.
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
Well I drove 175 miles today and the car felt 100% better in performance and no check engine light. Problem solved and fixed.
Thread Starter
Drifting
Joined: Jul 2006
Posts: 1,840
Likes: 7
From: no. jersey Photo by Stro
St. Jude Donor '08
BANK 1&2 LEAN.