"Boost pressure too high" fault at 5,000 rpm on stock N54 335i?

Drivaar · 02-28-2016, 09:06 AM

Hi everyone,

My car, a stock 2007 N54 335i with 107,000 miles, is suddenly getting a "boost pressure too high" fault when accelerating with the engine at 5,000 rpm or so (I had it read using an OBD computer -- I don't know the exact fault code though).

At that point, the car goes into limp mode, which still works, but the fact that I can reproduce this fault is worrying me.

It's never had any engine modifications (I've owned it for its entire life) and I'm wondering what's going on. I have not had much luck via Google search, as all the results are related to tunes.

I'm actually in the middle of trying to decide whether to keep the car itself, so if there is a big repair involved, that would be a big minus.

Thank you all!

engineer73 · 02-28-2016, 10:58 AM

Have you checked your boost control solenoid and boost pressure sensor to make sure they are functioning correctly? It shouldn't really be a big repair if it either of those two items.

Donutz · 02-28-2016, 06:30 PM

I had this recently. I changed my boost solenoids and vacuum lines and the issue has gone away (knock on wood).

Jeff@TopGearSolutions · 02-29-2016, 11:05 AM

Likely boost solenoid, especially if they are original on an 07. It's a quick and relatively cheap fix.

You'll usually hear them buzzing and making odd noises.

kmx · 03-01-2016, 05:05 AM

Quote:

Originally Posted by Jeff@TopGearSolutions

Likely boost solenoid, especially if they are original on an 07. It's a quick and relatively cheap fix.

You'll usually hear them buzzing and making odd noises.

when you say buzzing do you mean while the car is idling?

Drivaar · 03-01-2016, 09:23 PM

Thank you very much for the tips!!

Jeff@TopGearSolutions · 03-01-2016, 09:30 PM

Quote:

Originally Posted by kmx

when you say buzzing do you mean while the car is idling?

Im pretty sure they make a little noise at idle.

However, erratic noises or noises that are loud is usually a sign it's on the way out.

expressfish · 03-02-2016, 10:28 AM

take them off and shake them, I picture the insides like a plunger that sucks and pushes air inside a cylinder wall. Next ones I replace Im going to gut to see what the insides are. Anyway when you shake them a new one is really tight and the worn ones I replaced were really loose. Its almost like they are unable to make compression anymore.

02-28-2016, 09:06 AM	#1
Drivaar Lieutenant 78 Rep 463 Posts Drives: BMW Join Date: Aug 2010 Location: Earth iTrader: (0)	"Boost pressure too high" fault at 5,000 rpm on stock N54 335i? Hi everyone, My car, a stock 2007 N54 335i with 107,000 miles, is suddenly getting a "boost pressure too high" fault when accelerating with the engine at 5,000 rpm or so (I had it read using an OBD computer -- I don't know the exact fault code though). At that point, the car goes into limp mode, which still works, but the fact that I can reproduce this fault is worrying me. It's never had any engine modifications (I've owned it for its entire life) and I'm wondering what's going on. I have not had much luck via Google search, as all the results are related to tunes. I'm actually in the middle of trying to decide whether to keep the car itself, so if there is a big repair involved, that would be a big minus. Thank you all!
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02-28-2016, 10:58 AM	#2
engineer73 Mechanical Engineer P.E. 27 Rep 114 Posts Drives: Space Grey 2009 e93 Join Date: Nov 2015 Location: Charleston sc iTrader: (0)	Have you checked your boost control solenoid and boost pressure sensor to make sure they are functioning correctly? It shouldn't really be a big repair if it either of those two items.
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02-28-2016, 06:30 PM	#3
Donutz Lieutenant 140 Rep 476 Posts Drives: 335i Join Date: Sep 2015 Location: Toronto, eh iTrader: (2)	I had this recently. I changed my boost solenoids and vacuum lines and the issue has gone away (knock on wood).
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02-29-2016, 11:05 AM	#4
Jeff@TopGearSolutions 3472 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Likely boost solenoid, especially if they are original on an 07. It's a quick and relatively cheap fix. You'll usually hear them buzzing and making odd noises.
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03-01-2016, 09:23 PM	#6
Drivaar Lieutenant 78 Rep 463 Posts Drives: BMW Join Date: Aug 2010 Location: Earth iTrader: (0)	Thank you very much for the tips!!
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03-02-2016, 10:28 AM	#8
expressfish Private First Class 39 Rep 175 Posts Drives: 07 E92 335I Monaco Blau Join Date: Mar 2015 Location: Texas iTrader: (1)	take them off and shake them, I picture the insides like a plunger that sucks and pushes air inside a cylinder wall. Next ones I replace Im going to gut to see what the insides are. Anyway when you shake them a new one is really tight and the worn ones I replaced were really loose. Its almost like they are unable to make compression anymore.
	Appreciate 0 Quote