Description
OBD-II Trouble Code Description for P0173 BMW
Fuel Trim
What does this mean?
OBD2 Code P0173 BMW definition:
This code is one that surfaces with certain makes of automobiles more than others. In writing this article I’ve added Mercedes-Benz-specific info since it seems that M-B (and VW) are most prone to having this P0173 BMW surface along with misfire codes or other fuel trim codes. P0173 BMW means there was a malfunction in the computer’s control of the air:fuel ratio. It also indicates that the fuel trims reached their limit of adding fuel while trying to compensate for a actual or perceived rich condition. When the fuel trims reach their rich correction limit, the PCM (Powertrain Control Module) sets a P0173 BMW, indicating a problem or malfunction in the fuel trims. It may also have a P0170 BMW referring to the same malfunction but on bank one.
Symptoms
Possible sumptoms of OBD code P0173 BMW
MIL (Malfunction Indicator Lamp) Illumination Start and stall Poor fuel economy Black smoke at tailpipe Hesitation/misfire at idle or under load
Causes
Possible causes of OBD code P0173 BMW
Potential causes include a vacuum leak, unmetered air leaks Fuel saturated engine oil Leak in turbo air charge hoses (if equipped) Possibly bad O2 sensor (If Mercedes, may require adaptation with M-Benz compatible scan tool.) Oil contamination in MAF connector or O2 sensor connectors. Also check ignition coils, cam and crank sensors, and oil sensor for leakage contributing to oil intrusion in wiring harness. Defective MAF (Mass Air Flow) sensor (especially on Mercedez-Benz and other European autos. There are a lot of problems with aftermarket MAF sensors.) Defective fuel pressure regulator Leaking camshaft adjuster solenoids (Mercedes-Benz). NOTE: for some Mercedes-Benz models there is a service recall for a crankcase vent hose located under the intake manifold. It should be checked for leaks/cracking and also operation of check valve in the hose. The check valve should flow only one way.
Possible Solutions
It should be stated right off the bat that the most common problem associated with this code is the MAF sensor or air mass meter. This is especially the case with Mercedes-Benz and Volkswagen and other European cars. At time of writing, you don’t normally see this code with American-made cars, and minimally with Asian, and, to be honest, I have no idea why. It appears to me that the PCM (powertrain control module) logic used by some European car manufacturers to set a P0173 BMW (or P0173 BMW) fault code simply isn’t used by American vehicle manufacturers. It is more common to see P0171 BMW, 0174, 0172, 0175 codes set with regard to fuel trim malfunctions on American cars. There is very little information on the setting conditions for a P0173 BMW, or P0173 BMW, but what information that is available almost seems to be a redundancy of the P0171 BMW,4,2 & 5 setting conditions. I’m sure there’s a reason for it, but I can’t get anyone to tell me what that is. The similarities between them may be why we don’t see this code surface on domestic vehicles very often. It’s simply unnecessary. So, simply put, if you have a P0173 BMW, your PCM noticed that the fuel trims reached their rich correction limit. Basically it’s adding fuel to try to compensate for a lean condition, real or perceived. If you have this code and access to a scan tool, observe the MAF sensor reading in grams/sec. The reading will be different for different automobiles, so get a good spec. I’m going to stick with what would be normal for a Mercedes (1.8L), since they have the bulk of the trouble. Expect to see at idle 3.5-5 g/s (ideally). At 2500 RPMs with no load it should be between 9 and 12 g/s. On road test, at WOT (wide open throttle) it should be 90 g/s or well above. If it’s not in specs, replace it. Be careful of Ebay MAFs. Often they don’t work according to OE specifications. If the MAF checks out and there is no oil intrusion at the connector, check fuel pressure and ensure that there are no leaks at the regulator internally or externally. Check all vacuum hoses and confirm none are cracked, disconnected or missing. Make sure there are no vacuum leaks at the intake manifold gaskets or tears in the air supply hose. If the engine is turbo charged, be sure the hoses are in good condition and have no leaks. Leaking turbo pressure hoses could cause a rich condition. Inspect the condition of crankcase vent hose under intake manifold and operation of check valve in the hose. (In the “What are the causes?” section) If there doesn’t appear to be any problems with the fuel pressure, MAF or vacuum hoses, then inspect the O2 sensor connectors for oil intrusion. A bad O2 sensor could cause a P0170 BMW, or P0173 BMW. Repair cause of oil leak and replace oil-fouled O2 sensor. Article written by Dale Toalston
The OBD2 Code Information Be Applicable For BMW:
2013 BMW X6 M50d,2013 BMW X6,2013 BMW X5 eDrive Concept,2013 BMW X5 Security Plus Concept,2013 BMW X5 M50d,2013 BMW X4 Concept,2013 BMW X1,2013 BMW Pininfarina Gran Lusso Coupe,2013 BMW M6 Coupe US-Version,2013 BMW M6 Coupe,2013 BMW M6 Convertible,2013 BMW M5 US-Version,2013 BMW M550d xDrive Touring,2013 BMW M550d xDrive,2013 BMW M4 Coupe Concept,2013 BMW M135i,2013 BMW Active Tourer Outdoor Concept,2013 BMW 7 ActiveHybrid,2013 BMW 750Li,2013 BMW 7-Series,2013 BMW 640i Gran Coupe,2013 BMW 640d xDrive Coupe,2013 BMW 6-Series Gran Coupe UK Version,2013 BMW 6-Series Gran Coupe,2013 BMW 5 ActiveHybrid,2013 BMW 4-Series Coupe Concept,2013 BMW 3 ActiveHybrid,2013 BMW 3-Series Touring,2013 BMW 3-Series Long Wheelbase,2013 BMW 1-Series 3-door,2012 BMW i8 Spyder Concept,2012 BMW i3 Coupe Concept,2012 BMW Zagato Roadster Concept,2012 BMW Zagato Coupe Concept,2012 BMW M5 UK Version,2012 BMW M5,2012 BMW M3 DTM Champion Edition,2012 BMW M3 CRT,2012 BMW M135i Concept,2012 BMW Active Tourer Concept,2012 BMW 650i Convertible,2012 BMW 640d Coupe,2012 BMW 6-Series Coupe,2012 BMW 6-Series Convertible,2012 BMW 3-Series,2012 BMW 1-Series Urban Line,2012 BMW 1-Series Sport Line,2012 BMW 1-Series Coupe,2012 BMW 1-Series Convertible,2012 BMW 1-Series,2011 BMW i8 Concept,2011 BMW i3 Concept,2011 BMW Z4,2011 BMW X5,2011 BMW X3 xDrive35i,2011 BMW X3 xDrive20d,2011 BMW X3,2011 BMW X1 xDrive28i,2011 BMW M5 Concept,2011 BMW M3 Pickup Concept,2011 BMW M3 GTS,2011 BMW M3 Frozen Gray,2011 BMW ConnectedDrive Concept,2011 BMW ActiveE Concept,2011 BMW 750Li,2011 BMW 5-Series Touring,2011 BMW 5-Series Long-Wheelbase,2011 BMW 5-Series,2011 BMW 335is Coupe,2011 BMW 328 Hommage Concept,2011 BMW 3-Series Coupe,2011 BMW 3-Series Convertible,2011 BMW 1-Series M Coupe US Version,2011 BMW 1-Series M Coupe UK Version,2011 BMW 1-Series M Coupe MotoGP Safety Car,2011 BMW 1-Series M Coupe,2010 BMW Z4 UK Version,2010 BMW Z4 GT3,2010 BMW Z4,2010 BMW X6 M,2010 BMW X6 ActiveHybrid,2010 BMW X5 M,2010 BMW X1,2010 BMW Scooter C Concept,2010 BMW M3,2010 BMW Gran Coupe Concept,2010 BMW ActiveE Concept,2010 BMW 7 ActiveHybrid,2010 BMW 760Li,2010 BMW 7-Series High Security,2010 BMW 6-Series Coupe Concept,2010 BMW 5-Series Gran Turismo,2010 BMW 5-Series ActiveHybrid Concept,2010 BMW 320d EfficientDynamics,2010 BMW 135i Coupe,2010 BMW 135i Convertible,2009 BMW X6 UK Version,2009 BMW X6,2009 BMW X5 xDrive35d BluePerformance,2009 BMW X5 Security Plus,2009 BMW X5 Security,2009 BMW X3 Limited Sport Edition,2009 BMW M3 Saloon UK Version,2009 BMW M3 Race Version,2009 BMW M3 Convertible UK Version,2009 BMW M3 Convertible,2009 BMW EfficientDynamics Concept,2009 BMW 750Li,2009 BMW 730d,2009 BMW 7-Series UK Version,2009 BMW 7-Series,2009 BMW 5-Series Gran Turismo Concept,2009 BMW 335d BluePerformance,2009 BMW 3-Series UK Version,2009 BMW 3-Series Touring UK Version,2009 BMW 3-Series Touring,2009 BMW 3-Series,2009 BMW 1-Series Convertible UK Version,2008 BMW X5 M-Package,2008 BMW X1 Concept,2008 BMW M5 Touring,2008 BMW M3 Sedan US-Version,2008 BMW M3 Sedan,2008 BMW M3 Coupe US-Version,2008 BMW M3 Coupe UK Version,2008 BMW M3 Coupe,2008 BMW M1 Concept,2008 BMW M-Zero Concept,2008 BMW GINA Light Visionary Model Concept,2008 BMW EfficientDynamics Concept,2008 BMW Coupe Range,2008 BMW 7-Series ActiveHybrid Concept,2008 BMW 650i Convertible,2008 BMW 635d Coupe,2008 BMW 530i,2008 BMW 5-Series Touring,2008 BMW 5-Series Security,2008 BMW 5-Series,2008 BMW 135i Coupe,2008 BMW 128i Convertible,2008 BMW 1-Series Range,2008 BMW 1-Series Coupe,2008 BMW 1-Series Cabrio,2008 BMW 1-Series 5-door,2008 BMW 1-Series 3-door,2007 BMW X6 Concept,2007 BMW X6 ActiveHybrid Concept,2007 BMW X5 4.8i,2007 BMW X5 3.0d,2007 BMW X3,2007 BMW M6 Convertible Neiman Marcus,2007 BMW M6 Cabrio,2007 BMW M5,2007 BMW M3 Concept,2007 BMW Hydrogen 7,2007 BMW Concept CS,2007 BMW 530Li,2007 BMW 335i Coupe,2007 BMW 335i Convertible,2007 BMW 1-Series tii Concept,2006 BMW Z4 Roadster,2006 BMW Z4 M Roadster,2006 BMW Z4 M Coupe UK version,2006 BMW Z4 M Coupe,2006 BMW Z4 Coupe,2006 BMW Mille Miglia Coupe Concept,2006 BMW Art Car Collection,2006 BMW 7 Series High Security,2006 BMW 760Li,2006 BMW 750i,2006 BMW 750Li with Shadow Line,2006 BMW 750Li,2006 BMW 330i,2006 BMW 325i Touring,2006 BMW 320si E90 WTCC,2006 BMW 320si,2006 BMW 320d Touring,2006 BMW 320d,2005 BMW Z4 Coupe Concept,2005 BMW X5,2005 BMW X3 EfficientDynamics Concept,2005 BMW X3,2005 BMW M6,2005 BMW M5,2005 BMW H2R,2005 BMW 630i,2005 BMW 545i Touring,2005 BMW 530xi Touring,2005 BMW 530xi,2005 BMW 530d Touring,2005 BMW 330i M-Package,2005 BMW 320d Touring,2005 BMW 130i M-Package,2005 BMW 130i,2005 BMW 120i UK Version,2005 BMW 120i,2005 BMW 120d,2004 BMW X5 4.8is,2004 BMW X5 4.4i,2004 BMW X3 3.0i,2004 BMW X3 2.0d,2004 BMW H2R Hydrogen Racecar,2004 BMW Concept M5,2004 BMW 645Ci Convertible,2004 BMW 645Ci,2004 BMW 5 Series,2004 BMW 530i,2004 BMW 530d,2004 BMW 330Ci Coupe,2004 BMW 330Ci Convertible,2004 BMW 330Cd Coupe,2004 BMW 325Ci Coupe,2004 BMW 320Cd Convertible,2004 BMW 318Ci Convertible,2003 BMW Z4 2.5i,2003 BMW Z4,2003 BMW M3 CSL,2003 BMW 760Li E66,2003 BMW 325ti Compact,2003 BMW 3-Series Compact,2002 BMW xActivity Concept,2002 BMW X5 4.6is,2002 BMW CS1 Concept,2002 BMW 7 Series,2002 BMW 760i,2002 BMW 760Li Yachtline Concept,2002 BMW 740d,2002 BMW 730d,2002 BMW 3-Series Touring,2002 BMW 3-Series,2001 BMW Z8
Note:
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