P0170 FAULT CODE for FUEL TRIM malfunction
 

In 1996 I purchased my brand new 1996 Benz C 280 and Production Date OCT 1995. Today I have 170K miles on it.
I live in Virginia. My VIN # is WDBHA28E3TF340808. Over a year ago or so the spark plugs were replaced. 3 months ago oil and oil filter was replaced.
All of a sudden, my "Check Engine" light came on and so I used my ACTRON Scanner CP 9175 tool, and I get this exact message: P0170 fault code for fuel trim malfunction Bank 1 of 1. I contacted the Mechanic that I go to often, and he said that "he thinks" it is the MAF, looking at about $250.00 Parts and $100.00 labor. I then went to Google and found some SUGGESTIONS. I purchased a can of BG Mass Air Flow Sensor Cleaner $10 Bucks, I removed the Sensor ONLY, but it was very clean, I sprayed it anyway, but it under the sun to dry, I then removed the MAF housing and I sprayed it too! After confirming that all is dry, I put everything back together, I started the car, everything is fine, but the "Chaeck Engine" light is still "ON". I did not erase it, I am now driving to reach over 100 miles and see if it will go away. My office is just 4 miles from home, so it will take a while to reach 100 miles. I believe that the Fuel Filter has not been changed for the last 6 years. I found the Air Filter Very dirty, I went to two auto supply stores and no one have it, and so I ordered a MANN from autohausaz.com, will be in shortly, I cleaned the air filter as well as the housing, vacumed it, was full of bugs, sand, leaves etc. The car runs great and smooth, in fact it starts better than before. By big question to you the Group is: What should my NEXT course of actions be, without making financial mistakes? I really do not think it is the MAF, only because it was very clean already, and I also handled it with great care, and I only sprayed the bottom.

Check engine....
 

I also have been getting the same error code, but have been resetting it as I don't believe it is a REAL problem. I would like to get to the root of the problem.
In regards to your "check engine" light, you have to reset that also. Key in "run" position, reset codes with your analyzer, light out. I use an OBD gizmo and my laptop to do this.

Good luck.