EPC and CEL

[dkell426]

Tonight my EPC light and CEL light came on. The car was running fine, and then when the EPC came on there was no power. Pedal was to the floor and i was only able to go about 5-10 mph. I pulled over and shut the car off for a couple seconds, and when i started it again I had the same problem. I pulled over again and let the car sit for about 2-3 minutes and when I started it again, it was fine. Just the CEL was on. I drove it home, and it drove fine like nothing had happened other than the CEL being on. Once I got home, I let it sit for a little bit thing maybe the CEL would clear itself, and it started back up again, but the CEL was still there. I am hoping to get it scanned tomorrow to see what the issue could be. If it was a serious issue, would the EPC have cleared itself? I never had this issue or light on before, other than when my MAF was unplugged. Hopefully it is nothing serious, I just spent the money on my timing belt, this is all i need.

[dkell426]

Checked today and the CEL is no longer on, and the car seems to run as it always has. Scanned it just to see what the code is and i got these:

17579/P1171/004465 - Angle Sensor 2 for Throttle Actuator (G188) Implausible Signa
17953/P1545/005445 - Throttle Valve Controller: Malfunction
17511/P1103/004355 - Oxygen (Lambda) Sensor Heating; B1 S1: Performance too Low
17976.P1568-Idle speed control throttle pos mech malfunction

I cleared the codes, and everything seems to be fine now. I'm hoping it was just a weird occurrence, if not, hopefully cleaning the throttle body and aligning it will help. NOt sure why it is throwing an O2 sensor code. I have no cat and unitronic tune for that setup.

[dkell426]

nothing?

[mescaline]

EPC = electronic power control. It's your throttle body that is acting up. Take it off, clean it up and that's it. Sometimes it gets too dirty and can't close/open properly OR you might want to inspect wiring as well.

[dkell426]

thats what i figured, i just thought it was strange that all the lights went off and stayed off over night. once i get ahold of a vag-com i will clean the tb and align it. thanks for the reply

[dkell426]

So after about 3 months of no issues, and a 300 mile drive to maryland, the problem is back. It has happened twice since the last time. Only when I hit a big bump, the esp and epc light will come on, no CEL. It fixes itself after I shut the car off for a few minutes. One of the times it happened was today, i hit a bump and then the lights came on. I pulled over, restarted and it idle'd really rough, so i waited a little longer and it was fine. When i got home i popped the hood and there was smoke coming from the valve cover/downpipe area. My guess is that it may be a loose 02 sensor since that was a code when I first scanned it or maybe the TB just really needs a cleaning. Also, the constantly smells like something is burning off when it gets hot, but it does not smoke or smell like burning oil from the exhaust. any help would be appreciated.

[codergfx]

my friend recently had this problem on his gti or similar problem, take out the TPS and clean it with break cleaner his was soaken in oil. also could be a bad ground since youre saying it happens when you hit bumps.

[dkell426]

ill look into that, i hope it's not electrical.

[bluewolf2001]

my car is doing the same. did you ever figure out anything

[dkell426]

my car is doing the same. did you ever figure out anything

cleaned the grounds and checked the wiring in january and it was all fine until last week. cleaned the throttle body and it happened again tonight. im going to change the pre-cat o2 sensor, i heard that they could cause this issue. hopefully that will help. i'll let you know if i solve it for good

[bluewolf2001]

i sure as hell hope its not the o2 sensors i just replaced them suckers 4 months ago....what grounds did you check

[dkell426]

i sure as hell hope its not the o2 sensors i just replaced them suckers 4 months ago....what grounds did you check

i brought it to my mechanic and he checked so im not sure. it happened again to me yesterday but this time i was bale to drive, just not get above -10 vacuum. restarted and it was fine. im thinking about just picking up a new TB and seeing how that works. its not throwing a CEL so im kind of stuck. its just annoying, i never know when its going to happen.

[dkell426]

So, I still have not solved this problem. I have replaced the throttle body, adapted it, cleaned the MAF and everything seemed well. On the way to H20, again, hit a bump and boom, EPC, ASR light. Pulled over, restarted and everything was good, except it was idling high. Made it down there, home, around town with no problems other than a rougher idle on start up and high idle. Scanned it tonight, along with a misfire code for 3 of 4 cylinders, I pulled:

-16891/P0507/001287 - Idle Control System RPM: Higher than Expected.

I am eliminating the throttle body since it is BRAND NEW, I am not to good with wiring but I am leaning towards a broken, loose connection somewhere, I just dont know where to look other than the connection to the throttle body . I will have to do a vacuum leak test as well but, would a leak cause an intermittent problem like this? I am sick of going over rough roads and constantly checking the dash to see if these lights pop on. Any more help or tips would be greatly appreciated.

[DMVDUB]

Check MAF as well.

If you're competent and confident in your skills, pull off the throttle body and give it a full makeover. clean it up inside and out, polish it up inside, make sure the throttle plate is seated properly and replace. It's better to give it a shot on your own before shelling out the cash for a new tbody.

[dkell426]

Check MAF as well.

If you're competent and confident in your skills, pull off the throttle body and give it a full makeover. clean it up inside and out, polish it up inside, make sure the throttle plate is seated properly and replace. It's better to give it a shot on your own before shelling out the cash for a new tbody.

I cleaned my old one, same issue. There is a brand new one on the car now but it wasn't the issue even though all codes and symptoms previous to this pointed to that.

[r3coil]

fyi i had the same issue this week - epc and CEL for tpps (throttle pedal position sensor)... wouldnt let me go into boost and car idled weird..

ended up being a break in the wire in between the pedal and the ECU.. had my mechanic look it over and he found it after a bit. running fine now

[dkell426]

any tips on tracing a broken or lose wire without loosing my mind?

[bluewolf2001]

i had this problem twice in the last few months, and i forget when i posted to this fourm which it was. but i fixed problems both times. with a new TB, MAf, Air pressure sensor. then i had problems another time but it slid a intercooler coupler without me relising fixed it instantly(rough idle, not boost, mis fires when trying to pull boost). you run a FMIC?

[dkell426]

i had this problem twice in the last few months, and i forget when i posted to this fourm which it was. but i fixed problems both times. with a new TB, MAf, Air pressure sensor. then i had problems another time but it slid a intercooler coupler without me relising fixed it instantly(rough idle, not boost, mis fires when trying to pull boost). you run a FMIC?

no front mount, stock side mount.

[BMP #1736]

You should check your maf wires. I recently had this problem and found that the wire measuring the air flow was all buggered up. Fixed that and she's good as new