1998 Ml320 - P0173

[everes]

I'm a new member and think this site is GREAT!!!

Anyway, I has been reading some previous posts where the Check Engine Light has come on with P0170/P0173 and its been advised that 90% of the time it's the mass air flow sensor. In my 1998 ML320 ONLY code P0173 registered. Do you believe it is the same problem or something different since P0170 did not also register.

Thanks again,

Erik

[joe p]

Trim malfunction. Odds are the a/f is had it providing the air boot is in good shape and not leaking. If you have access to a SDS, look at actual values in ME2 for mass air flow, idle should be around 16 and matted it should hit 400+. (it'll hit it momentarily about the time it hits the rev limiter)


Joe

[stevebfl]

MB says specifically not to use scan data to evaluate the air mass meter. The reason for this is that they use other methods to adapt to the miscalibration and they reform the value that would be displayed into the corrected value. In other words if its wrong it gets corrected and the data you see isn't real

The way we look at the values is to look at the adaptation values. You are undoubtably running at 1.32 or so in lower partial. The way we proceed from there is to replace the AMM and drive it around the block. Usually the the thing readapts at around 1.00 because unless your fuel pump is taking a dump it always the AMM. If you come back at 1.25 or above the statistics lied and check that chinsy flexhose clamp as Joe pointed out.