(M3 evo) MSS50 INPA 155&44, car misfire after car wash, etc

[kyrix1st]

Hello, I currently ride '98 S50B32 M3. Here are two codes that came up

MSS50 INPA 155 DME control unit memory master fault
MSS50 INPA 44 oil level sensor fault

Symptoms
1. My car starts fine. Cold start stays at 1,000 rpm, then drops to 650 or so.
2. Car seems to run rich, I get horrible gas mileage compared to E85 Z4 (M54B30). I think i'm getting around 3-4km/L or 12-14 mpg. I don't accelerate like an idiot, hardly ever past 4k.
3. Occasional misfire/knocking after a car wash. Car knocks/misfires horribly but after I turn off ignition and restart, goes back to normal. I have a non-stock cold air intake (gruppeM.) and I believe water may be getting in through the nose.
4. Car smells like fuel after I press throttle hard, and in general.
5. I recently heard a "pop" sound from the front of the driver's side while accelerating from 2nd gear, low rpm (left) with windows down. At first I thought it was an engine blow(:0_0) but car drove fine after and no more noise.

Any feedback is much appreciated. Thanks for reading!

[galuple]

Hand wash or a machine wash? I've heard of lots of people who have gotten their DME wet in a car wash and fried them

[kyrix1st]

Hand wash or a machine wash? I've heard of lots of people who have gotten their DME wet in a car wash and fried them

Hey, it's a hand wash by a professional. I thought problem of water clogging was solved for post 95 models?

[MParallel]

Hey, it's a hand wash by a professional. I thought problem of water clogging was solved for post 95 models?

Nah, the drain was never changed. I pulled the rubber out. It doesn't do anything, but potentially clogging it up.

The oil level sensor is fairly common. You should also have a blinking oil level warning light on the dash on startup

[kyrix1st]

Interesting. I used INPA to delete error message and error code 155 no longer pops up(44 still does). However when it popped up, it said intake temperature -48.00C. Maybe some kind of temp sensor has to do with it?

[kyrix1st]

So this time I decided to give it a tweak and start and engine cold, read the codes and clear error memory to see which one pops up again. Interestingly, only 44 (oil level sensor) pops up. When 155 DME code popped up, I also saw -48c intake air temperature. So I suspect it's got to do both with engine temp and sensors directly related to car running a bit rich. Will keep it updated.

[MikeC164]

Hi there just curious if you were able to figure this one out? I’m having the exact same issue DME error 155 and intake temp reading -48