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My car loses power, the epc light comes on, then it loses most of its power

(2001 Volkswagen Beetle)
in Corinth, NY on June 25, 2009
My car loses power (when i am on the gas pedal, it starts pulsing/jerking around), and sometimes, not all the time (i believe it would everytime if i kept driving), the epc light comes on, then it loses most of its power (some sort of system that saves the car ultimately). If i turn the car off and sit for a while, it goes away (again depending on how long a drive it for).This happened to be a couple of months ago, and i brought it to Garvey(VW dealer). It tripped a couple of codes...they didn't know what was wrong,so they reset them. Ended up bringing it back next day, they called aorund and no one knew. They cleaned the grounds and that worked...up until a couple weeks ago, it started off slow and began happening everytime i drove the car. I brought it back, it tripped the same codes, plus 2 more! This time it tripped a throttle body code. They still didn't know what to do (didn't feel safe using my money to guess on what to fix...even tho i got slammed twice already to find out that they didn't know what to do). We picked the car up, and they told us, after sitting in the parking lot all day, it runs crapy and the EPC light is on right from the start. PLUS, now my check engine light is on (it was NOT on when it went there) Does anyone have any suggestions? We were thinking about puting a whole new throttle body system in the car, but it is $600, so if there is a cheaper solution, i would love that =] Thank You!
Displaying 16 answers & 11 comments
Popular Answer
on July 09, 2010
The EPC light is connected to a pressure sensor in the block. Open the oil filler cap, release the pressure (and check your oil while you're at it). If you don't have a real problem, the light should go out.
on September 07, 2010
My 05 Jetta has had 2 throttle bodies replaced. And now my check engine light is on and I have a 'vacuum leak'. I refuse to go back to the dealership; what a rip off. I have my mechanic looking into it but it has taken him nearly 2 weeks to decipher the codes, replace sensors, change plugs, coils...with still no fix! My suggestion is one i am going to heed myself...never buy another Volkwagon.
on September 07, 2010
If the code that you are getting is a P0171 or a lean mixture code, tell your mechanic to look at this article that I wrote about that code, here is the link below. On a VW, the Mass Air Flow Sensor is a common suspect. I do Emissions work in California and deal with these problems all week long, so I am pretty familiar with them.
on November 13, 2010
First's called a Volk(s)wagon. If your not bright enough to choose a different garage; then, the fault is yours and yours only. Buy a code reader and start your own diognostics. A fool and her money are soon parted.
on May 19, 2015
It's actually Volkswagen. Volk is German for people, wagen = wagon. Nevertheless, since it's a German company, it's Volkswagen.
on June 26, 2009
There is definitely something worn out in your EPC system. I would also check your engine computer. You need to get your car to a good VW independent shop. The Throttle Body codes are common on VW with EPC and this usually means that the Electronic Throttle Body needs replacing and reprogramming. This is common on VW and Audi.

Did you have a dealer put in the Throttle Body or did you do it your self? And I guess the shop that you took it to did not do a very good inspection of the basics, i.e. vacuum leaks, scan the car etc. They should have seen the lean condition in the scan data. But it sounds like they did not even do this. I am glad that your car is fixed but this is really a shame that the vacuum leaks, etc were not repaired. I ahev never seen a vacuum leak set EPC codes, they usually set P0171 (system too lean)
on June 30, 2009
So, we put a new throttle body in the car, and it made NO difference. My boyfriend and his dad were looking under the hood, his dad just touch the pressure regulator hose that was conected from the intake manifold to the pressure regulator, and it fell right off. We replaced that and now it works. So i was going to be charged over $600 bucks for a $.50 fix.
on December 15, 2010
I am having the exact same issue, where is the pressure regulator hose? can you get a pic of it? 2001 vw jetta 2.0 gl.
on June 07, 2010
I have a vw jetta
i does the same thing as yours
the problem to it is the throttle
i bet if you put it on the car will run as new
or you can just buy the sensor to it
its about $50 on ebay
its just the cables of the throttle burnted up
buy the sensor and the throttle is fine
on July 12, 2010
we replaced the pressure regulator hose, and now a year later, all is still good! =]
on July 20, 2010
Do you know the exact name of the hose or a part #.. I need to get my hands on one of these fast. .. thank u
on August 08, 2010
I had the same problem with my car and thanks to this forum I was able to solve the problem. The problem ended up being the throttle body but I did call the pressure regulator hose to the mechanics attention. Thanks again
on November 04, 2010
is it the oil pressure hose or the fuel pressure hose? i got the 01 jetta thats been a pain. with the same problems..spent time at the dealer with no help. took it to some vw special shops in san jose, who said it was all fixed and then a week later problems came back. the bank 1 to lean code comes up from time to time. got the cat replace things werked for a little while but the issus still come around. thinking about drivin the car out to a open field and burning the damn thing.
on May 13, 2014
I have a 2012 Polo Vivo - had the same symptoms. EPC light comes on - car looses power. Took it to a Bosch Auto Electrical Centre. They found a small crack/leak in the intake-manufold (close to the throttle-body). It's NOT a sensor/wiring/electronic gas pedal/throttle-body problem. It's a minor leak at the intake-manufold or leaks by small pipes connected to the intake-manufold. Bosch technician used sealing glue - patched the small leak/crack - reset on diagnostics - had the car back to 100% condition within hours and cost me next to nothing. Very impressed - have had no problems with dreaded EPC light since then. Car runs like a dream. Hope this is some usefull info. :o)
on June 21, 2014
I never did get around to saying how my EPC got fixed.
Turns out my Thermostat and my Crank Shaft Sensor needed to be replaced.
I havent had any more EPC issues since these were changed out.
EPC could be a long list of things, these just happened to be my two.
on May 07, 2012
Well I own a 2001 1.8t wolfsburg and it sucks like every other VW other people I know have owned(key word...OWNED)they sold got rid of them which I wish I could have done. Anyway I had and still have trouble with my throttle body all the time and all you can do is take the main hose off and spray the inside down with carb cleaner.....if the sensor reads wrong it will throw codes for the throttle peddle, the epc, and your breaks don't want to work properly. My mechanic told me to just spray it out, because VW has no way of correcting this problem. You can replace the TB and it will start to do the same thing again over time....they are prone to this junk and the VW company doesn't care. My mechanic only works on VW and has done this for many years...I had been going to him when I had my first VW bettle(1972) I am now 36 and still go to him for all my problems. This however is the last VW I will ever own!!!!
on June 14, 2012
I have 2002 VW Jetta. I have EPC light + Engine check light. I took it to the VW dealer at Bellevue, WA. First time they said "No problem" and reset the codes. In a week I got the same problem and they replaced "throtte pedal". 3rd time I got the same issue. Now they say it is "Throttle Body".

It is a big rip-off. VW Jetta sucks. I hate to maintain this car.
on April 29, 2016
Just because you don't know what you're doing or how to maintain your car doesn't give you the right to knock a great car...go buy a chevy that you can handle and stfu.
on December 11, 2015
2002 jetta had a battery draw. I left a charger on it for a day at 10 amps. I found the draw on the battery, but now my epc and engine light is on and the car will start and then die. Could I have damaged something with a prolonged charge and how can I clear the codes myself?
on December 11, 2015
You can clear the codes by removing power to your battery for awhile. 10 minutes should work.
EPC can be alot of things.
Turns out my two issues were the Thermostat and my Crank Shaft Sensor.
My mechanic replaced those and I never had a reoccurance yet.
You may of done some electrical damage to one of the sensors in the system.
EPC is a bitch to diagnose I've been told.
on February 28, 2016
EPC SOLVED for now2009 passat 2.0 tsi Epc intermittent that went into limp mode with code P0221 throttle/pedal position sensor/switch "B" I took all three electrical connectors off around the throttle body cleaned inside connectors with circuit cleaner and lubed with electrolytic grease and reassembled ... NO EPC NO CODES FOR THE FIRST DAY IN 3 WEEKS I'm keeping my fingers crossed......Update its has been weeks without epc or any code at all....FIXED
on October 21, 2014
we have had the same problem with two different jettas and we have found that the pcv tubes are broken. they go under the intake manifold and they are a part of the crankcase ventilation system, look into that and replace the fuel pressure regulator hose if it is kinked or old.
on March 09, 2011
I spoke to a VW tech in Bay City Mi, he said it has to do with ABS. My car is doing the same thing and I already have 600bucks into it with no results..
on March 15, 2016
took the car to another place today replaced timing belt and water pump. not helping . they said the Moto is damaged and need to be replaced keeping my fingers crossed as the motor cost around 2000
on January 02, 2016
had problems withe EPC light coming on and car jerking and ultimately dies. I researched all the possibilities. I changed the fuel filter and now all that was wrong is working. When i dumped the fuel out on the filter it was black. Cars runs like a boss now. I bought this car used at 120,000 on it. The guy sold it pretty much could not figure small prob;ems out. It is a 2005 VW passat gls 1.8t
on June 26, 2015
We share a common problem. I am beyond frustrated and have even written to Germany with all my faults, lack of interest from them. I have had an "exhaust workshop" bleeping at me, loss of compression (3 cylinders running only) and EPC wording with "engine workshop" bleep. I own a 2002 VW Polo 1400 16valve. We have had 3 garages in Christchurch, New Zealand put her on their diagnostic machine and the following has been tried or done:
Plug 1 and 2 swopped; New coil on plug 1, fault remained; 2 fuel injectors replaced; Engine temperature sensor replaced; Petrol filter, fanbelt, battery, all plugs and coils replaced; Valves recut and reseated and a new Oxygen sensor fitted. By now I could have bought a new Toyota! My wee car seems to have lost the hiccuping but exhaust workshop light bleeps at me still!???
on May 26, 2014
I am updating my prior answer from May 26, 2014. To cut to the chase, it appears my issue all along was a throttle body wiring harness, which if faulty can send numerous false codes relating to sensors, plugs, etc. I was told that this wiring harness commonly goes bad on the VW CC's, mine being a 2009 Luxury 4 cylinder turbo. Once replaced, I have not had any EPC lights or other code lights come on. I spent $422 to have the throttle body wiring replaced. Prior to that, around $1,000 on new plugs, new coils, a new battery (that was legit, strangely it nearly eliminated the sputtering, but only for a short while), a coolant temp. sensor on the lower radiator hose (P2181 code), a new thermostat, water pump and a 2nd coolant temp sensor located within the water pump housing, and FINALLY the throttle body wiring harness. During this 11 month period of codes, I had many. P0171, P0172, P0174, P02181 and others that the final repair shop did not provide. What ticked me off is that the same repair shop that replaced the water pump/thermostat/coolant temp sensor is the one that finally said it was my wiring harness. Makes me wonder if they knew that was a possibility before the water pump. After the $700 and some water pump/sensor/thermostat replacement, I started getting the 171 and 172 codes a month later. When I took it back, they said there were multiple codes and according to a TSB, they all pointed to the wiring harness. I could have replaced it myself, but it involves cutting numerous wires and splicing to the new harness plug.

May 26 2014.
Same exact issue here, the EPC light and check engine lights came on after I accelerated a bit hard in traffic. I have an 09 VW CC Turbo with just over 60k miles. Had the manifold intake gasket and flapper replaced at 45k with a carbon cleanout conducted at the same time. I was sure my issue would be related, but turned out it was the #3 spark plug and coil that were bad (P0303). I have a feeling though that when I accelerated maybe it blew some gunk into the plug. Probably didn't even need the coil. The repair was completed by a local franchise service center for $214, which included one replacing all four plugs ($47.96), the coil on #3 ($79) and labor of $87.20. They wanted to complete a throttle body cleaning for $119, but I declined.
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