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EPC stands for Electronic Power Control this is you Electronic throttle system malfunction indicator.
Has your battery just been replaced or was the vehicle "jump started"?
Your throttle may require adaptation. This vehicle is equipped with an electronic "fly-by-wire" system. Any time the battery power is disrupted and reconnected the throttle should be adapted.
I recommend you try adapting the throttle. If you have access to a VW/Audi capable scanner go into 01-Engine electronics, retrieve, record and erase any fault codes, go into 04 - basic settings, display field #60. The throttle adaptation should take place, after which you should get a "pass" or "fail" value.
You may also be able to adapt the throttle without a scanner on this year model. To do so, first I suggest you do a capacitance discharge. If you remove the battery terminals from the battery and connect or jump them together, turn on the key to the "on" position for about 1 minuet, turn off the key, then reconnect the terminals to the battery. Now turn the key to the on position, but do not start or touch the gas pedal. The throttle should do it's adaptations in the first 10 seconds or so. You should be able to hear and see the throttle do this. Start the vehicle and it should be adapted. The main disadvantage to this method is you will NOT get a "pass" or "fail" value to confirm the adaptation.
If this does not correct the condition and extinguish the light, the first method described would be recommended as well as interrogating the fault memory of the on board diagnostics.
Should you have further questions on this matter, please do not hesitate to ask. I want you to be 100% satisfied with my answer.
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The "already tried" portion of your question was not displayed when I answered your question. The 11.8 v woukd be low, did you jump start the vehicle? I have seen the act of jump starting cause the throttle control to fail. So, to answer your question, no, I do not think a low battery could have influanced this, but the jump starting or charging may have.
The only downside to the capacitance discharge, would be that you do not get a "pass" of "fail" after adaptation takes place.
As to the lifeless sound when turning over, a common cause for a no start or intermittent no start would be a failed fuel pump. Typically when the fuel pumps fail it is after sitting for some time, usually cold. Typically the car may fire and run or sputter for a few seconds then die and not start at all (does this sound familiar?).
If the vehicle won't start have someone else crank over the starter while you go back to the area of the right rear door, listen underneath the car for a "buzzing" of the fuel pump. If you hear the pump and it is still not starting the fuel pump is likely not the cause. If however you do not hear the "buzzing", bang on the bottom of the fuel tank with your hand or if you have a big rubber or plastic hammer that works better. Often this will giggle the electrical brush contacts of the fuel pump enough to allow the motor to start, as should the engine at this time.
If this does not work, and it still won't buzz and start, there are other possible causes for the fuel pump not to get it's supply voltage. At least now you know that the fuel pump is not running and narrows down the possibilities.
If it is buzzing and won't start you need to check for spark. If you do not know how, contact me and we will go that route should it be necessary.
The fuel pump is the most likely cause for this year model. I suggest you try this if it does not correct the condition let me know and I will continue to assist you.
Another possibility for no start would be flooding due to carbon on the valves. The 1998 - 2001 2.8L 30 valve motors (ATQ, AHA) are prone to "flooding" when cold. This condition is typically brought on after a short drive cycle on a cold engine. A classic example would be starting the vehicle cold, pulling it out of the garage, and shutting it off, attempting to start the next morning. When attempting to start cold in the a.m. the engine will be difficult to start, and run poorly if at all. This is usually caused by carbon particles (byproduct of combustion) getting stuck on the valve seats and not allowing them to seal. The reduction in compression does not provide sufficient pressure and the combustion event can not occur so fuel is unburned and the cylinders become "flooded" with unburned fuel. Could this have been the condition when you last ran the engine?
Please explain how this all came about from the last time it was running untill it would not start.
I hope I have answered your questions and addressed your concerns, should you have any further questions regarding this matter, please do not hesitate to ask. I want you to be 100% satisfied with my answer.
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Yes, So just so we are on the "same page" This does sound like the carbon issue. Here is my "full blown" carbon flooding reply.
The 1998 - 2001 2.8L 30 valve motors (ATQ, AHA) are prone to "flooding" when cold. This condition is typically brought on after a short drive cycle on a cold engine. A classic example would be starting the vehicle cold, pulling it out of the garage, and shutting it off, attempting to start the next morning. When attempting to start cold in the a.m. the engine will be difficult to start, and run poorly if at all. This is usually caused by carbon particles (byproduct of combustion) getting stuck on the valve seats and not allowing them to seal. The reduction in compression does not provide sufficient pressure and the combustion event can not occur so fuel is unburned and the cylinders become "flooded" with unburned fuel.
This condition can be worsened if the vehicle is run on substandard fuel for an extended period. This engine is designed to run on premium "top tier" fuel. It can be run on mid-grade "top tier" fuel with reduced performance. Only "top tier" fuels have sufficient detergents to prevent the build up of carbon and fuel deposits in the injection system and combustion chambers. See toptiergas.com for more details.
If this cold start/run condition is caught in the early stages, you can disconnect the fuel pump fuse (in the fuse panel on left of dash) it should be the third fuse from the bottom (blue/15) on the first row. There is a fuse legend on the inside of the cover to confirm location. Then try cranking over the engine for some time with the accelerator pedal to the floor, possibly almost one minuet and see if it begins to catch. If so reinstall the fuse while still cranking. If it does start try and maintain the RPMs at about 2,500 until it clears up. The vehicle must be driven and allowed to fully warm-up before shutting down.
If the cylinders are suspected of excessive carbon build up the Audi dealer should have a fuel injection cleaning system that uses Wynn's cleaning solution. It is run through the injector rail on a running motor in place of the vehicles fuel system which has been disabled. This cleans the injectors, the back sides of the intake valves, and the combustion chambers to some extent. When combustion chambers have excessive carbon buildup you can remove the spark plugs and poor the solution directly into the cylinders and let it soak for several hours, after which time it is expelled and the vehicle is restored to running order. As an owner I DO NOT recommend you try to do this yourself, there are many steps and precautions that are best left to a professional. What you could do would be to periodically run a can of fuel injector cleaner through the fuel tank to help reduce deposits.
Based on your question I assume you are a repair shop. If the vehicle is very flooded, I suggest after removing and drying the spark plugs, you disconnect the fuel pump fuse when starting it as described above. I have had instances where I had to remove and dry the plugs a couple of times. When you do have the spark plugs out, if you have a air blow gun with a long nozzle, I suggest blowing out the cylinders in an attempt to dry them. Then its just a matter of waiting for the carbon particles to clear from the valve seats. It also helps to have a strong jumper battery (not a charger) hooked up for this extended cranking.
Jake "The Audi Doctor"
Jake- I'm NOT a repair shop. Truly a personal car owned by my daughter. I'm a mechanical engineer with some experience with engines, etc.
I'm very impressed with your service. I'll use again if needed, and I'll definitely pass on to friends! Thanks again.
That last paragraph was part of a previous answer I neglected to delete. Many of these conditions are "pattern failures", like the carbon fouling issue. It takes time to type a complete, concise, answer. Rather than type out the same answer over and over again, I save these common answers to file and use, amend, or modify them to suit the specific condition. This allows me to provide my clients with the highest level of response possible. And does not totally rely on my memory.
This carbon issue even "bit" me the other day. It was about 25 degrees f the other morning and I was working with another client here on Just Answer. He was describing a shift-lock sequence when starting his A6. I went out to my A6 to confirm, whilst doing so I briefly started the vehicle (15 seconds?), and shut it off. A half dozen hours later, my wife went to use the vehicle and it "carbon flooded" upon start attempt. Once this occurs the vehicle typically cranks as if there is no compression. I took me many attempts of disconnecting the fuse and cranking with a jumper battery to eventually clear and start the vehicle.
All "experts" are not created equal, so if you wish my level of response in the future, please request me. You can also open any future questions with "Question for Jake or The Audi Doctor"
Thank You! And Happy New Year!