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gomi_otaku
gomi_otaku, Technician
Category: Audi
Satisfied Customers: 3430
Experience:  VW certified technician, Chicago VW/Audi Training Center, Seattle VW/Audi Academy
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Audi 2009 A4 Quatro turbo: Hello, I drive, a 2009 Audi A4 Quatro

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Hello, I drive, a 2009 Audi A4 Quatro turbo charge, i have had issues with an EPC light and now i have a check ingine light on car seems to run ok. Any Ideas? please help as a Single mother i dont have tons of money for replai bill, thank you.
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Here to answer automotive questions and make you feel comfortable and become familiar with your product

The EPC light and the check engine light will always turn on together. EPC - There is a relay in the engine control module box that fails. This is the main power relay. The Check engine light noticed something wrong within that circuit and has stored a fault. I will say that the relay is failing or there is a problem in the circuit. You can go to a pep boys or autozone and have them check then list the faults here and we can better tell what is the failure. Most likely it is the relay.
Customer: replied 3 years ago.
Relist: Answer quality.
As long as the check engine light is not flashing, you are not experiencing misfires- so you won't be doing damage to your catalytic converter. As you said, it seems to be driving OK- but anything that sets a fault should be corrected if possible.
If you go to your local Autozone or other large chain store, they will often be able to scan your system for faults FOR FREE- just don't let them try to sell you anything, they are not trained specifically in AUDI and will just take the recommendations that their scan tool gives them. So if you get the faults scanned by them, and come back here and post them into this thread, I can take a look and we can get a good idea what your problem is, and how urgent the repair is needed.
Customer: replied 3 years ago.
Took car in to have malfunction indicator lamp check engine light problem scanned and was told it is code P0299.
Customer: replied 3 years ago.


You replied
Monday, June 24, 2013 8:30 PM EST
Took car in to have malfunction indicator lamp check engine light problem scanned and was told it is code P0299.
Edit

P0299 is "turbo underboost", meaning that the system is not seeing the amount of pressure it believes the vehicle should be producing. A few different things can cause this issue.
First, you may have a loose hose- and when the turbo goes into boost, it opens up and dumps some of your pressure. You would likely notice this as it may misfire, or run poorly when you really try to get on the gas.
Another common cause for this, though usually in conjunction with other faults, is the Mass Air Flow meter. This measures the amount of air going into the engine, so the system can deliver the correct mixture of fuel for that air. This is a math issue- if you get a certain amount of air in, the system will expect that air to be able to reach X pressure. If the MAF is reading incorrect, then it is calculating wrong, and will expect a totally different pressure than it is getting. So it is possible that this is the issue, but like I said, usually you get other faults for the MAF- though sometimes a "generic" scanner at an auto parts store may not read some "proprietary" faults.
You may actually have a failed turbo bypass valve- I have seen these recently where the diaphragm ruptures, allowing the system to bypass a small amount of air all the time. The only way to know this for sure is to remove this valve and inspect it. It is under the turbo and will be hot if the car has been running.
gomi_otaku, Technician
Category: Audi
Satisfied Customers: 3430
Experience: VW certified technician, Chicago VW/Audi Training Center, Seattle VW/Audi Academy
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Customer: replied 3 years ago.
Would it be safe to drive my car, I can't afford to fix now, if taken to, an Audi delearship what cost am I looking at?