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EPC light issue

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epc hard start high rpm issue light
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46K views 30 replies 13 participants last post by  Ghia83  
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#1 ·
today, I was just thinking to my self how nice my little car has been to me.

Then when I got out of Lowes, I tried to start the car. It didn't start the normal, "Errr errr Voommmm". The car does this once and a while with no codes or lights. I usually let it crank 3 to 4 turns and let off the key and then let the car sit for a bit if it doesn't start each time. About the 3rd time, it started with the ELC light on and 1200 RPM. I let the car run for a bit and the RPM never went down, so, I put it in gear and went straight for a shop (thinking, it is running, i can drive it most of the way so the tow would be cheaper).

Got to a VW shop, park, turned the car off. Let it sit for about a min, and try to start the car again. Started normally and ran fine. The RPMs where normal.

Now, I have always had a issue with the car being boggy. Once and a while, I can a real pull with 15 to 20psi on my K03 chipped. Most of the time, it doesn't feel like it is pulling more then 10psi with the boost gauge shows 20. Not really an issue for me, because im not racing it, but something to me is telling me something is wrong. THere is ZERO codes prior to this issue... :(

So, my search gave me,
Engine Power Control
I think this means the ECU is limiting output of the engine. Mine went on when my engine speed sensor started crapping out. My other symptom was difficult warm starts. Dealer replaced part and all was good. I think I paid 90 bucks for the part plus an hour "labor".
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and

The EPC light means something is wrong in the drive-by-wire path, the "gas pedal" potentiometers or the electric motor-controlled throttle body, etc. I do not know if that relay qualifies, and I'm not even 100% sure what it does without research, but I assume it powers the ECM up when the ignition is on. Certainly the ECM is part of the electronic power control system, but I don't know if faults with the ECM are going to light the EPC light rather than the check-engine light.

When the car is having this problem, does the check-engine light come on with the rest of the lights when you just turn on the ignition without starting the car? It should, if it doesn't, the ECM may not be alive.
Click to expand...
My engine light Does come on with the car is in Check Mode.

These posts where from 2006. I am looking for any updated information then that (if it is out there)

2004 1.8T, auto, AWM, 103k, APR, K03, N75J - inline MBC, CIA, Light mod exhaust, TB done with all the extras done in the front, bolt down Audi Coil Packs with NGK plugs (i hate my plugs).
 
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#2 ·
Bumping the post for some guidance.

Also, anyone in the Richmond area with a Vag-Com. Looks like santa is not getting me one this year.

Car still running fine again, no lights. I did nothing to it and a little worried. Driving to NJ in January, GA in February, and possible CT drive in April.
 
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#5 ·
OK folks.

Today, my car crapped out on me 3 more times (while running running around town).

It was running fine. I parked, went in shopping, came out and it wouldn't start. Took 6 tries before it started and had the EPC light on and was running at 1,400 rpm. I let it run for about 1min, shut the car off, then restart. It started up fine, ran right with no lights. While the EPC was on, there wasn't a engine light.

This happened three times today...

Please Help!
 
#6 ·
I don't know about where you live, but in some states, the DEQ will give you a CEL scan for free. Also I know there is a website that allows you to locate people with VAG-COM. I can't remeber the exact name of the site, but I am sure you could fnd it on google, or maybe someone else will chime in who knows what I am talking about.
 
#7 ·
Autozone. Buy an ebay cable for like $30. Oh wait, can you run that on a Mac? I think you a Mac owner?
 
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#9 ·
EPC light usually means problem with ecu. Mine and others had problem with soldered chip encryption boards.
 
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#14 ·
Actually, this is somewhat false. The EPC light can be triggered by an ECU problem, but the EPC system specifically deals with the drive-by-wire, as mentioned above.

The EPC (electronic powertrain control) system deals solely with monitoring the electronic accelerator pedal and moving the throttle body to match positins. Most likely, there is a problem with the accelerator pedal.
 
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#18 ·
The ECU controls the system, and triggers this seperate light for DBW problems (the same way the ECU now triggeres a seperate check light for loose gas caps in newer cars) so scanning the ECU, address #1, should reveal any faults. IIRC, you can also look at the diagnostic data to make sure the throttle pedal is responding properly and the signal coming out of it is smooth.
 
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#19 ·
sounds like it could be the engine speed sensor. I had a similar problem with my 04 earlier this year. The car would start fine but while riding through town it would cut off when stopped at traffic lights..it would eventually start after a couple tries.
..I think I may have had a flashing EPC whenever this happened but I did have the car scanned at Autozone or Advance and thats what the problem was.
 
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#20 ·
Ditto PiSSAT4motion.

My 02 cut off like that. No problems after Engine Speed Sensor was replaced.

Had EPC light on after I drove too quickly thru a puddle which turned out to be deeper than I thought. Too much water must have splashed up, because EPC light went on, RPMs went up, but power went down. Not sure if this was related to the ESS issue though.
 
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#24 ·
You guys should also do a search for cleaning the throttle body. Not to difficult and it can make quite a difference. A dirty TB can (and does) spout EPC lights and codes and nonsense. The symptoms posted here are a bit different then a dirty TB but as I said it helps across a broad spectrum of things and it isn't too difficult to do.
 
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#25 · (Edited)
Just got the car scanned.

16706 Engine Speed Sensor (G28): No Signal
P0322-004 No Signal/Communication - Intermediate

16684 Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded - MIL ON

16687 Cylinder 3: Misfire Detected
P0303 - 001 - Upper Limit Exceeded - MIL ON

I will decode the other two unless someone beats me to it. Just need to get inside where it is warmer. I am guessing Over Boost (still/again...)

Looks like I have to buy a Speed Sensor. Anyone have a spare? :)


EDIT: Looked up the other codes and now wondering what happen to my car. I am hoping the engine speed sensor is causing the miss fire. just replaced the spark plugs 1,000 miles ago. have A4 Bolt down coil packs. Shouldn't be getting any miss firing.

ideas?
 
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#29 ·
I have a flashed APR93.

Am I looking for a 'speed sensor' or a 'knock sensor'?.

Also, If someone has a link for a part number list for the 2004 passat, that would be most helpful because I need to find screws that disappeared and a few other little items here and there. The link I have is from germany and now wants a 'log in'. I can't read or speak germany, so I am SOL.
 
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