Awful engine sounds and no power after stepping on it for

atikovi · **Joined:** Mon Jan 16, 2012 12:05 pm **Posts:** 20

the first time since picking up this CRD yesterday. Drove it home 50 miles at 65-70 mph and it ran great but I drove gently because the CEL was on. Read the codes, P1186 inlet pressure sensor circuit and P0299 turbo underboost. Deleted the codes and P1186 came back immediately. Went to pick up dinner today and on the way back decided to get on it a little. Maybe half throttle, at which point the engine started to make some pretty bad sounds, and it had no power. This was 3 miles from home. Took some side streets back as I couldn't get much over 25, but finally made it back. Scanned for for codes again, and P0300 misfire code shows up. Erased it and a half hour later fired it up again. Seems to run ok for now. What would cause all that engine noise like a bad rod knock, but disappear later? And what is P1186 referring too, it's not in the service manual?

TKB4 · **Posted:** Wed Aug 14, 2019 9:42 pm

The p1186 and p1189 codes are related to the Inlet Air Pressure or IAP sensor also called the Mercedes sensor on the CRD s .It is located on the side of the air intake lid . It is the lower one that is toward the engine and almost touches the boost hose on that side. It is also notorious for the weak clip breaking off or not connecting good. I would remove this connector clean it and reattach and if necessary use wire tires tape or whatever you need to make sure it stays snuggly on. If this doesn't help I would replace it.

For the low boost code even though it cleared I would clean the MAP sensor or replace it.
It might be worth checking all the injector connections too and maybe an Italian tuneup or some power service cleaner.

I have had the p0300 misfire code at the same time as the p1189 before. The misfire code didn't return.

Awful engine sounds and no power after stepping on it for

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