OBDII CODES P0171 & P0174

  • Tiny
  • sponge27
  • Ford Mustang

I own a 1995 Mustang V6 3.8 liter and recently my check engine light came on. I borrowed a scanner and the codes that I got were P0171 and P0174. I have learned that these mean system too lean (bank 1) and system too lean (bank 2). What can cause this problem and how do I remedy it?

Do you
have the same problem?
Monday, February 13th, 2006 AT 5:24 PM

1 Reply

  • Tiny
  • peppermrj
  • Member

Code P0171 may mean that one or more of the following has happened:

The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) Can cause the MAF to become dirty if the filter is over-oiled
There could be a vacuum leak downstream of the MAF sensor.
Possible solutions include:

In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace if necessary
Check for a dirty fuel filter and proper fuel pressure

Good luck and let us know.

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Wednesday, February 15th, 2006 AT 8:44 PM

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