2003 C230 mercedes.Has anyone solved problem P0171 code?

Question

Is it the mass air flow sensor or the 02 sensor?

Answer 1

HI there,

Without a scan tool that can read the live data it is difficult to tell which of these is the problem. Normally if the maf sensor is bad you will have some driveabiity issues. Hesitation, bucking and rough running. When the O2 sensor is the problem then the code will appear without these issues. Also, you could have a vacuum leak or low fuel pressure causing the problem as well.