Does anyone know what a code 173 means? The code diagnosed at Autozone says,

"The PCM has determined that during testing, the fuel compensation value for bank 2 exceeded the specified range."

What can I fix to correct this.

I have reset it a couple of times by taking off the battery cable, but it keeps coming on at low RPM's.

Thanks for any suggestions.

Thanks,

Chris

It's coming back on becasue the adaptation values are exceeding the limits preset. To get a completely accurate diagnosis, you'll need to go further and read the adaptation values. This will tell you if the ME system is compensating rich or lean. If the system is showing 1.32, (maximum) then you probably have a bad Air Mass Meter. If the values are low (.62, minimum) then it's most likely the fuel pressure regulator.

If the adaptation values are high, swap in a new AMM, and recheck the adaptation values. If they are normal, then you have solved the problem and simply reset the CEL and go on your way.

In most cases, CEL codes of P0173 and P0170 are the Air Mass Meter.

Also, don't return to AutoZone. They won't be of any futher help. You need access to Star Diagnostic System to access adaptation values.

Sounds like a mass air sensor to me.... Make sure the air filter is fully and properly sealing to the air box, or when the dirt bypasses the filter it will take out the mass air flow sensor. I see it all the time with Non-Mercedes filters. They warp, or the foam rubber portion isn't cut properly and a poor seal results.

K&N filters are also a main culprit of AMM failures.

This is my story with the CEL:
https://mbworld.org/forums/clk-class-w208/66240-check-engine-light.html