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P0172 system to rich bank1 error

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Hi colleagues


I need your help my car show this code and i dont know from where i can begain can anyone help me


My car subaru legacy 2010 2.0 cc ej204 cvt


I get code p0172 system too rich bank1 error


Please need your help


I take the car to dealear one one month ago and tgey say u meed change fuel pump and they already change it


After 15 days error came again and they cant determine what is the problem !!

Edited by kalabala2005
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I'd take a look at the spark plugs. If one of them is black (and maybe wet), that'd point to a sticky fuel injector at that cylinder, and if all of them look a little black, that could be a bad fuel pressure regulator. "Normal" is slightly brownish, you can come up with lots of examples by doing a web search for "spark plug color chart".
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other things that I would look at BEFORE tearing the car apart.


1. Fuel trims? are they pegged?

2. MAF, at idle fully warmed up it should be roughly 2.0Grams a second (roughly equal to engine displacement)

3. data log your O2 sensors.


Most of the time it will be MAF failure or a vacuum leak in the system.

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  • 3 weeks later...

i take car to the dealer and he say that pcv valve was damaged and stuck on always open he change it and car now go normally


and i have one small question A/F correction#1 range is from -20 till +20 on idle is this normal or i have air leak on the system


and how to check air leak on my system ?

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Now that it is getting colder out I would make sure your maf sensor, throttle body and PCV valve are spotless. If you have 60-120k miles you could need a spark plug(highly recommend different swivels and extensions if doing yourself)

Also I would only use Top tier gasoline in your car. Exxon, BP and Mobil have been known to have the best detergents mixed in with their gasoline. Oil may be the blood of the car, but they put any brand of gas in their car when they shouldn't.


Sent from my SM-G935V using Tapatalk

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