Code P0172 and P0175

checked and got these 2 pending codes prompted:
P0172 Fuel Trim System Rich Condition
P0175 System Too Rich

Should I have the Fuel System checked and what these do look like? Anything would be considered to replace, like Fuel filter or pump, etc.,

Common fault is a faulty MAFS but poor spray pattern of the injectors, fuel pressure too high, faulty HO2Sensors and other things can set the DTCs.

I would look at the LTFT and STFT while driving to see what readings you get.

The good thing about working at the dealer (back when I did) was that you can swap a part from another car to see if the readings changed so the diagnosis went quicker.

Throwing a $200 MAFS at the car and finding the same result was discouraging.


So much appreciated, Bob!

Good luck. You will need it.

Personally I would

  1. get the fuel tank level to half way
  2. disconnect the battery for at least 30 mins
  3. give the car a drive on the highway

Mointor over a month and see if the lights/codes return