Vacuum Leak with code 4873?

Xerix · 03-15-2015, 11:04 PM

Hey Guys,

I think I am having a vacuum problem with my car. My car has thrown code 4873: Charging Pressure Control, HIG-Pressure Stage, Control Deviation: Charging Pressure Too Low/Positive Control Deviation. I got this code definition off the internet so it might be wrong. But I'm presuming this has something to do with the vacuum system? Or perhaps turbo charger?

So Im thinking it might be a vacuum leak because when I step on my break when starting my car, sometimes its hard like a rock like when you press on it when the car is not on too many times. This never used to happen as far as I can remember. Nothing seems to be off with my car currently asside from the slightly off fuel economy I think I might be having. Breaks feel pretty normal as well, but then I never really paid too much attention to the feel other than I liked it.

Does anyone know how to start to diagnose where a leak might be? I know I need to blow some smoke into the system, but I dont know what to safely disconnect to do it.

Any help is appreciated.

Yozh · 03-16-2015, 01:59 AM

First is to look at the turbo bypass valve and it's associated pressure converter and vacuum lines. I do not purport to be an expert, but look up my thread entitled "Code 4530". There are also other threads that deal with vacuum line and pressure converter diagnostics. Please also check your red boost hose for leaks. It may throw all kinds of codes with charge pressure deviation. Please also remember that there is also a compressor bypass valve that may need to be checked.

Xerix · 03-16-2015, 09:15 PM

Ill look into what you suggested.

I can tell you right away that the Red Boost Pipe is covered in oil. I can see the side of it from the top front of the car near the radiator fan.

Xerix · 10-09-2017, 12:59 PM

So it turned out my problem was an easy fix. My vacuum line cracked from the rear pressure converter to the vacuum tank on the front of the holder facing the front of the engine.

The hose was on a very tight 180 degree turn which finally broke under the strain. I found it when I blew some smoke into the vacuum line connecting to the EGR cooler.

I replaced it with some vacuum lines I bought and everything worked great.

A word of caution though. Remember to immediately clear your codes after the fix. Otherwise the computer will assume there is still something wrong with the turbo.

03-15-2015, 11:04 PM	#1
Xerix Private First Class 30 Rep 119 Posts Drives: 2010 335d Join Date: Jun 2014 Location: Toronto iTrader: (0)	Vacuum Leak with code 4873? Hey Guys, I think I am having a vacuum problem with my car. My car has thrown code 4873: Charging Pressure Control, HIG-Pressure Stage, Control Deviation: Charging Pressure Too Low/Positive Control Deviation. I got this code definition off the internet so it might be wrong. But I'm presuming this has something to do with the vacuum system? Or perhaps turbo charger? So Im thinking it might be a vacuum leak because when I step on my break when starting my car, sometimes its hard like a rock like when you press on it when the car is not on too many times. This never used to happen as far as I can remember. Nothing seems to be off with my car currently asside from the slightly off fuel economy I think I might be having. Breaks feel pretty normal as well, but then I never really paid too much attention to the feel other than I liked it. Does anyone know how to start to diagnose where a leak might be? I know I need to blow some smoke into the system, but I dont know what to safely disconnect to do it. Any help is appreciated.
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03-16-2015, 01:59 AM	#2
Yozh Colonel 870 Rep 2,615 Posts Drives: 2011 335d M-Sport Join Date: Mar 2014 Location: Wet Coast iTrader: (4)	First is to look at the turbo bypass valve and it's associated pressure converter and vacuum lines. I do not purport to be an expert, but look up my thread entitled "Code 4530". There are also other threads that deal with vacuum line and pressure converter diagnostics. Please also check your red boost hose for leaks. It may throw all kinds of codes with charge pressure deviation. Please also remember that there is also a compressor bypass valve that may need to be checked.
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03-16-2015, 09:15 PM	#3
Xerix Private First Class 30 Rep 119 Posts Drives: 2010 335d Join Date: Jun 2014 Location: Toronto iTrader: (0)	Ill look into what you suggested. I can tell you right away that the Red Boost Pipe is covered in oil. I can see the side of it from the top front of the car near the radiator fan.
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10-09-2017, 12:59 PM	#4
Xerix Private First Class 30 Rep 119 Posts Drives: 2010 335d Join Date: Jun 2014 Location: Toronto iTrader: (0)	So it turned out my problem was an easy fix. My vacuum line cracked from the rear pressure converter to the vacuum tank on the front of the holder facing the front of the engine. The hose was on a very tight 180 degree turn which finally broke under the strain. I found it when I blew some smoke into the vacuum line connecting to the EGR cooler. I replaced it with some vacuum lines I bought and everything worked great. A word of caution though. Remember to immediately clear your codes after the fix. Otherwise the computer will assume there is still something wrong with the turbo.
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