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Discussion Starter · #1 ·
Yesterday on the parkway before changing my air filter I got P2096 Post Catalyst Fuel Trim System Too Lean. I cleared it yesterday and it hasn't come back yet, but I don't understand why it's coming on still. I recently had my exhaust repaired so that isn't leaking anymore, my fuel filter was replaced 4 days ago, and my air filter was replaced yesterday. I don't know what else this car can possibly want from me :(
 

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Yesterday on the parkway before changing my air filter I got P2096 Post Catalyst Fuel Trim System Too Lean. I cleared it yesterday and it hasn't come back yet, but I don't understand why it's coming on still. I recently had my exhaust repaired so that isn't leaking anymore, my fuel filter was replaced 4 days ago, and my air filter was replaced yesterday. I don't know what else this car can possibly want from me :(
That is not a valid VAG code, and the description doesn't describe any possible situation.
You would do much better with VCDS-Lite unregistered (FREE)
 

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Some cars (ECUs) use the second O2 sensor for adjusting the fuel trim (instead of using the first one, like most cars). I think you should just treat the code like a "system too lean" and look for vacuum leaks.
If you use Torque app, look at the freeze frame and post back the info.
 

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That cable should be satisfactory, don't use the disk that comes with it.


VCDS Lite unregistered will scan all modules one by one, but it needs to be registered ($99) to run TBA, all modules in one scan, and some other operations.

This is how I set up my VCDS Lite, I later registered it.
1 - Get 409.1 VAG cable (About US $10)
2 - Download VCDS Lite and install in Windows. Ross-Tech: Home
3 - Download USB-Com Port driver and install in Windows. FTDI Drivers
4 - In Windows device manager; set the Com Port to Port 4
5 - In VCDS Lite, set the Com Port to Port 4
6 - Connect cable to PC and OBD port, switch on the Ignition and test the port.
7 - Select engine and scan

Note: If you only have a Mac, Intel-based Macintosh PCs will run Windows. Run Apple's Boot Camp to set up dual booting; you will need is a copy of Windows OS.
 

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You set the code when you had strong vacuum, low load and 1500 rpm. I am guessing engine braking/coasting or barely touching the accelerator. Even more likely a vacuum leak.
You can watch your short term fuel trim (STFT) or long TFT (LTFT) when you drive, for either banks. You can see if you get different numbers for the 2 banks, if it gets lean/rich when you accelerate (no vacuum, high load) or when you lift of the gas. This data should point you in the right direction to try and find the problem.
 

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Discussion Starter · #10 ·
You set the code when you had strong vacuum, low load and 1500 rpm. I am guessing engine braking/coasting or barely touching the accelerator. Even more likely a vacuum leak.
You can watch your short term fuel trim (STFT) or long TFT (LTFT) when you drive, for either banks. You can see if you get different numbers for the 2 banks, if it gets lean/rich when you accelerate (no vacuum, high load) or when you lift of the gas. This data should point you in the right direction to try and find the problem.
when I was sitting in my driveway it was -14.7 it literally didn't change. I had my foot off the gas when I screenshotted it. My bank 2 is around 20mpg. When I was driving to my bosses house (that screenshot was the ride there) I was getting 33-37 mpg the whole ride changing between 35-45 MPH.
 

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I though the screenshot is the freeze frame... Never mind.
I am not sure what app you use, but see if you can add to the screen something called "short term fuel trim". MPG won't tell you anything to troubleshoot your problem.
 

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Discussion Starter · #16 ·
Wait! I found it!! Didn't know it could do that :O it has catalyst temps and O2 sensor voltage too! I'm going to get that all out when I'm home from school and post my findings. And or bring them to a mechanic. Lol
 

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Just add STFT bank 1 and 2 and Long TFT bank 1 and 2. All the other ones you can play with later, right now we only need these to try to narrow down your problem. Keep in mind that while the app lets you add all kind of displays/gauges, not all of them apply to your car (bank 1 sensor 3 or 4 for example) or some data is not provided.
 

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Discussion Starter · #19 ·
Just add STFT bank 1 and 2 and Long TFT bank 1 and 2. All the other ones you can play with later, right now we only need these to try to narrow down your problem. Keep in mind that while the app lets you add all kind of displays/gauges, not all of them apply to your car (bank 1 sensor 3 or 4 for example) or some data is not provided.
 
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