2008 Audi S6 P1075 code after fuel additive

I used a fuel additive as I want to decrease the carbon buildup as these DI engines are heavily known for it, then several days later the CEL came on and Scanner read a code of P1075, the fuel/air ratio was running rich in bank 2. Are there any common issues in the 08 S6 that would cause this?

You might want to post this on Audi forums, there might be someone there that has had this happen.

The causes of a P0175 are below:

  1. Faulty front heated oxygen sensor
  2. Ignition misfiring
  3. Faulty fuel injectors
  4. Exhaust gas leaks
  5. Incorrect fuel pressure
  6. Faulty Mass Air Flow (MAF) sensor

Read more: https://www.autocodes.com/p0175_audi.html

For a V6, #5 and #6 can likely be ruled out since both banks would see a lean condition. #2 would likely throw a P030# misfire code for one or more bank 2 cylinders.

Since you have a scanner read the Long Term Fuel Trims (LTFT) at idle for each bank. Then drive the car on the highway and record the LTFT’s. Post them here. That should identify a leaking injector.

You should also compare both the upstream O2 sensors’ readings cold and after warmup. If you can strip chart the data in your app, watch how each O2 sensors changes over time.

I’d recommend these tests whether you have an Audi or a Chevy with a V6.

A fuel additive doesn’t prevent carbon deposits from forming on the intake valves on direct injected engines.

That’s because the additive doesn’t come in contact with the intake valves.



You mean “does not”, right?