p0170 code w/multiple misfire codes - PeachParts Mercedes-Benz Forum

dyazdani · #1 02-22-2004, 02:03 PM

I've got a '97 C230 with a CEL, codes p0170 (fuel trim bank 1) and p0300,301,302 (misfires on cyl 1,2).

I did a search before posting, found one saying the air mass meter is the likely culprit.

I replaced my AMM the other day, with a used one that came from a misdiagnosed MB elsewhere. The light came back yesterday.

Is there another way to diagnose the problem? Values I can observe with a code reader? (self adaptation, O2 sensor values, etc)

Thanks,

Benzmac · #2 02-22-2004, 02:18 PM

When you rechecked the codes, were they the same or did they change? I would bet the fuel trim code was gone.

That said, I would look long and hard at coil and wire resistor ends.

They fail frequently.

dyazdani · #3 02-22-2004, 03:46 PM

I just had the codes read today. Actually it was more the opposite, a while back it was just the fuel trim code. Now it's fuel trim and misfire. I changed the spark plugs a couple of days ago, so I know it is not a bad plug.

Is there any way to test the AMM? I don't even know if it's sending a signal anywhere.

dyazdani · #4 02-23-2004, 09:40 AM

Another piece of data. . . when I chagned the spark plugs the other day, they were black around the end except for a small area at the tip of each electrode tip (I had the Bosch 4 tip kind).

Is there a way to check the O2 sensors or to see what the mixture is running?

Thanks

dyazdani · #5 02-23-2004, 09:57 AM

I read somewhere that the fuel trim can be reset somehow with the factory diagnostic tool. Is this a requirement when you change MAF sensors?

I changed out the sensor, but that's it - didn't reset anything.

dyazdani · #6 02-24-2004, 01:17 PM

Anyone?