Persistent 28A0 Code on N55

[mragan]

Ned some help disanosing a Persistent on and off again 28A0 code which is “intake pipe absolute pressure, plausibility: pressure too high.

The code goes away after the car sits for a few days and then comes on only at low speeds such as when you are coming to a stop or higher speeds when you take your foot off the gas to slow down. Some times the code comes back on with in a few miles. But the other day I took it on a 100 mile trip and it stayed off the whole time.

BMW Service replaced the MAF sensor, and checked the fuel pump which was fine. They smoke tested the engine several times but could not find any leaks. They concluded it must be the camshaft bearing cap wear issue.

So I had an oil analysis done by Blackstone Labs and the engine is in great shape with 142,000 miles on it and shows no signs of abnormal wear. That does not surprise me because the engine runs smooth. Makes good power and gets over 21 MPG on a trip.

The only other thing I am digging into is a smote test done by a competent independent shop that said they found the waste gate vacuum tube nipples leaking and suggested a valve cover replacement. BMW might not have disconnected the vacuum tubes during their smoke test.

Any other thoughts on what it could be or the next steps for diagnosis?

Mike

[Lviv777]

I had a different issue but mine turned out to be a bad boost solenoid. Maybe check that out. I had an indy shop do it. But again my issue was somewhat different.

[cloudybimmie]

Originally Posted by mragan

Ned some help disanosing a Persistent on and off again 28A0 code which is “intake pipe absolute pressure, plausibility: pressure too high.

The code goes away after the car sits for a few days and then comes on only at low speeds such as when you are coming to a stop or higher speeds when you take your foot off the gas to slow down. Some times the code comes back on with in a few miles. But the other day I took it on a 100 mile trip and it stayed off the whole time.

BMW Service replaced the MAF sensor, and checked the fuel pump which was fine. They smoke tested the engine several times but could not find any leaks. They concluded it must be the camshaft bearing cap wear issue.

So I had an oil analysis done by Blackstone Labs and the engine is in great shape with 142,000 miles on it and shows no signs of abnormal wear. That does not surprise me because the engine runs smooth. Makes good power and gets over 21 MPG on a trip.

The only other thing I am digging into is a smote test done by a competent independent shop that said they found the waste gate vacuum tube nipples leaking and suggested a valve cover replacement. BMW might not have disconnected the vacuum tubes during their smoke test.

Any other thoughts on what it could be or the next steps for diagnosis?

Mike

i am having the same issue, Where you able to figure this out?