# mk4 GTI throttle issues/EPC light/engine cut-out



## runvdub (Mar 23, 2011)

So ive got an 02 1.8t gti 5 speed
The car ran fine and i decided to replace the front suspension components and change the oil. 
I didnt start/move the car for 2 days til it was done and when i started it, it seemed to be ok until i hit the gas pedal....NO THROTTLE RESPONSE and the EPC light was on

scanned and codes were P2128/P2133 and also the CEL for P0038/P0300
I removed the throttle body for a good cleaning and no luck.

Went ahead and purchased a second hand TB which im garunteed is Working. 
Yes i know i need a throttle body alignment. So my question is will this fix my Throttle issue?

BTW i need VagCom if anyone can hook me up to help :thumbup:


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## Scigano (Mar 10, 2011)

I hope I'm wrong, but check the condition of your O2-sensor wires. Are they frayed, cut, or damaged/exposed in any way?


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## runvdub (Mar 23, 2011)

I checked them all the way to the fire wall. No damage as far as I can examine.


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## Rmnorth1.8t (Jan 11, 2009)

I have had the same thing happen to my 04 1.8t . I run water/meth and it has seized 2 throttle bodies resulting with the same symptoms you are currently having. You might want to do a hard reset of the computer in the car to fully remove all fault codes. Hope this helps!


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## runvdub (Mar 23, 2011)

Will do when I get vagcom this week. If a TBA doesn't fix it


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## BMP #1736 (Dec 14, 2011)

I was having the same exact problems as you. 
I smoke checked my insane for leaks, did a tba, cleaned tb, and checked basically everything. The last thing i checked was the maf because i feel it's become a cliche around here.. Lol. 
But anyway, i noticed that with the maf unplugged my epc light stopped coming on. Its a fairly new (not reman) maf so i decided to check the wires from the maf to the ecu. And sure enough i found that the red wire (your maf wires may be dif) was almost completely cut and must have been shorting out or something. 
I fixed that and i haven't had the epc light come on since.


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## runvdub (Mar 23, 2011)

Oh really? I'll defly check that out tmrw. Not that It's a good thing but I hope it is the issue to make for an easy fix. 

Thanks


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## rodebaugh99 (Apr 14, 2010)

hey man I'm having the same problems with my car I replaced my whole gas pedal assembly as told to do from a bunch of people at h20 but it didn't fix me problem:banghead: so I was starting to think my ecu may be fried until I started researching and the only thing that I've noticed with the ecu frying is usually the car won't start or you will have the epc light and the traction control but I only have the epc light on if you guys could help me out it'd be great I'm going to check my o2 sensors today


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## DMACK (Dec 5, 2003)

In for you to figure it out? mine did the same i boosted it to 18psi and im mafless 630cc than epc light and asr came on and there was no throttle response. turned the car off and back on and its been fine for two weeks now? :screwy:


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## runvdub (Mar 23, 2011)

My MAF wires seem fine. I already checked my pedal plug and it's ok as we'll. Friday should be when I do the throttle body alignment.y traction control light is on now and then but that's because my wires were shredded but temporarily fixed them. O2 wires are fine as well but the sensors themselves might not be good but can't get them loose. 

My car shuts off after a few seconds, thinking its due to lack of intake intake to the manifold.


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## BMP #1736 (Dec 14, 2011)

Just an update

I'm still epc and cel free. I've also done a lot of reading up on our mafs. I've come to the conclusion that regardless of the code that's thrown, check your maf and wires first lol. 

The reason for my codes was the fact that the wire that was all effed up was the one sending the signal to the ecu telling it how much air was coming in. That signal also meets up with the one the accel pedal sends before actually going to the ecu. 

Before i fixed that wire the only codes that were thrown were for the accelerator pedal assembly and tb. 

All of those sensors are so intertwined with each other that they don't really know the root of the problem, just that there is one. If that makes sense.

If you don't end up finding the cause, the last thing u should do would be to make up some overlay harnesses. Cuz it's most likely an electrical problem.

Oh also idk if this was mentioned but check fuse #43


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## BMP #1736 (Dec 14, 2011)

Oh i forgot to ask you. Which wires were all chewed up? If you mean the wires for your maf then im pretty sure that's the problem. And i can get u a new harness for 10$ lol. That's what i ended up doing.

But if you're taking about your O2 wires then your probably shorted out your ecu and that's your problem


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## Scigano (Mar 10, 2011)

DMACK said:


> In for you to figure it out? mine did the same i boosted it to 18psi and im mafless 630cc than epc light and asr came on and there was no throttle response. turned the car off and back on and its been fine for two weeks now? :screwy:


Have you VAGCOMed your car to see what codes the ECU threw? What _you_ could be experiencing is the damned "Torque Sensor: Limit Exceeded" code.

Does it happen if you boost under certain condition only, or all the time (like part-throttle boosting throws it, but WOT is fine, or visa versa — details like that)?


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## runvdub (Mar 23, 2011)

Bmp #1746
I checked the wires for the MAF as well as the o2 sensors. All wires were fine still wrapped in tact. The wires we pulled apart on accident were near the oil filter (found out they are for the a/c). 

Anyhow, I can't wait for vagcom to show up in the mail so I can at least see if I can tinker with the problem and fix that TB. If not.. I'll recheck wires and see if I can figure out a new custom harness of some sort to find the issue. Which I'm sure I'll need help on that one. But thanks man. Will keep updated


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## runvdub (Mar 23, 2011)

So here it is. Finally got vagcom today and ran a scan and these are the results
(Also did a throttle body alignment and still no throttle)


VCDS Version: Release 11.11.4
Data version: 20120807

Thursday,11,October,2012,19:59:19:05301

Chassis Type: 1J - VW Golf/Bora IV
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
76

VIN: 9BWDE61J424020055 Mileage: 418250km/259888miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AWW.lbl
Part No: 06A 906 032 DL
Component: 1.8L R4/5VT G 0006 
Coding: 07500
Shop #: WSC 14390 
VCID: 6BDE291B19914540E47

5 Faults Found:
18039 - Accelerator Position Sensor (G79) 
P1631 - 35-00 - Signal too High
18042 - Accelerator Position Sensor 2 (G185) 
P1634 - 35-00 - Signal too High
17513 - Oxygen (Lambda) Sensor Heating; B1 S2; Heating Circuit 
P1105 - 35-10 - Short to Plus - Intermittent
17953 - Throttle Valve Controller 
P1545 - 35-10 - Malfunction - Intermittent
17953 - Throttle Valve Controller 
P1545 - 35-10 - Malfunction - Intermittent
Readiness: 0100 1100

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Address 03: ABS Brakes Labels: 1C0-907-37x-ASR.lbl
Part No: 1C0 907 379 D
Component: ASR FRONT MK60 0103 
Coding: 0021505
Shop #: WSC 00000 785 00200
VCID: 2B5EE91B89118540A47

4 Faults Found:
00285 - ABS Wheel Speed Sensor; Front Right (G45) 
008 - Implausible Signal - Intermittent
00283 - ABS Wheel Speed Sensor; Front Left (G47) 
012 - Electrical Fault in Circuit - Intermittent
00285 - ABS Wheel Speed Sensor; Front Right (G45) 
012 - Electrical Fault in Circuit - Intermittent
01314 - Engine Control Module 
013 - Check DTC Memory - Intermittent

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 6Q0-909-605-VW5.lbl
Part No: 6Q0 909 605 F
Component: 08 AIRBAG VW6 0202 0004 
Coding: 12344
Shop #: WSC 00000 
VCID: 3A70DC5F264B2CC82F1

5 Faults Found:
00592 - Seat Belt Switch; Passenger (E25) 
32-10 - Resistance too High - Intermittent
00591 - Seat Belt Switch; Driver (E24) 
32-10 - Resistance too High - Intermittent
00532 - Supply Voltage B+ 
07-10 - Signal too Low - Intermittent
01217 - Side Airbag Igniter; Driver Side (N199) 
32-10 - Resistance too High - Intermittent
01218 - Side Airbag Igniter; Passenger Side (N200) 
32-10 - Resistance too High - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1J0-920-xx5-17.lbl
Part No: 1J0 920 906 J
Component: KOMBI+WEGFAHRSP VDO V65 
Coding: 07232
Shop #: WSC 09128 
VCID: 2F66FD0BED09F96088F
9BWDE61J424020055 VWZ7Z0A3994656

4 Faults Found:
01176 - Key 
65-10 - Unauthorized - Intermittent
01177 - Engine Control Unit 
64-10 - Not Currently Testable - Intermittent
01314 - Engine Control Module 
49-10 - No Communications - Intermittent
01304 - Radio 
49-00 - No Communications

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901 
Component: Gateway KCAN 0001 
Coding: 00006
Shop #: WSC 09128 
VCID: F0E4BE77B0B72698515

2 Faults Found:
01314 - Engine Control Module 
49-10 - No Communications - Intermittent
01304 - Radio 
49-00 - No Communications

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 
Part No: 1C0 959 799 C
VCID: 3776C56B155931A0D0F


End ---------------------------------------------------------------------


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## Slimjimmn (Apr 8, 2006)

Unplug your rear 02 sensor and clear the codes and do a tb adapt


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## runvdub (Mar 23, 2011)

Slimjimmn said:


> Unplug your rear 02 sensor and clear the codes and do a tb adapt


That was my next move thanks. Not sure how I'm gonna get that rear sensor out but I'll find a way


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## BMP #1736 (Dec 14, 2011)

Just look up under the right side of car near your front door. There should be a black square that houses the o2 sensors plugs.

Just see which one goes to the rear and unplug it

The cover is held on by two 10mm plastic bolts


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## runvdub (Mar 23, 2011)

So i got a new o2 sensor. Cleared the code and still no throttle!?
There were other items scanned, but non related (airbag/door locks/abs)
Do these codes mean the ECU/ECM is shot or that something is wrong with the wiring harness?

VCDS Version: Release 11.11.4
Data version: 20120807

Tuesday,16,October,2012,17:50:37:05301

Chassis Type: 1J - VW Golf/Bora IV
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
76

VIN: 9BWDE61J424020055 Mileage: 418250km/259888miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AWW.lbl
Part No: 06A 906 032 DL
Component: 1.8L R4/5VT G 0006 
Coding: 07500
Shop #: WSC 14390 
VCID: 6BDE291B19914540E47

2 Faults Found:
18039 - Accelerator Position Sensor (G79) 
P1631 - 35-00 - Signal too High
18042 - Accelerator Position Sensor 2 (G185) 
P1634 - 35-00 - Signal too High
Readiness: 0100 1100

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1J0-920-xx5-17.lbl
Part No: 1J0 920 906 J
Component: KOMBI+WEGFAHRSP VDO V65 
Coding: 07232
Shop #: WSC 09128 
VCID: 2F66FD0BED09F96088F
9BWDE61J424020055 VWZ7Z0A3994656

4 Faults Found:
01176 - Key 
65-10 - Unauthorized - Intermittent
01177 - Engine Control Unit 
64-10 - Not Currently Testable - Intermittent
01314 - Engine Control Module 
49-10 - No Communications - Intermittent
01304 - Radio 
49-00 - No Communications

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901 
Component: Gateway KCAN 0001 
Coding: 00006
Shop #: WSC 09128 
VCID: F0E4BE77B0B72698515

2 Faults Found:
01314 - Engine Control Module 
49-10 - No Communications - Intermittent
01304 - Radio 
49-00 - No Communications


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## Anony00GT (Mar 6, 2002)

Bad O2 sensor cooked the throttle drivers in the ECU. Verify the O2 sensors and wires (with a meter, not visually), and then replace the ECU.


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## runvdub (Mar 23, 2011)

Anony00GT said:


> Bad O2 sensor cooked the throttle drivers in the ECU. Verify the O2 sensors and wires (with a meter, not visually), and then replace the ECU.


Oh joy! well i have a brand new 02 sensor. Hook that up then replace the ECU? 
What specificly needs to be done?

Find an ECU for 1.8t 5/6 speed, AWP does engine code matter?
Then how do i swap the ECU, electronically. I know how to pull it out.

Your help is greatly appreciated, but the bad news is not


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## Anony00GT (Mar 6, 2002)

runvdub said:


> Oh joy! well i have a brand new 02 sensor. Hook that up then replace the ECU?
> What specificly needs to be done?
> 
> Find an ECU for 1.8t 5/6 speed, AWP does engine code matter?
> ...


Yeah, this isn't exactly an uncommon problem. I've seen it caused by bad O2 sensors, and on cars with big downpipes, O2 sensor wires melted against the pipe.

You're going to need an ECU that matches the EXACT part number as yours to start. Then you need to find someone who can match the new ECU to the immobilizer in your car (cluster, keys, etc). Basically you're limited to the dealership for this, not much availability in the aftermarket. You might be able to find a tuner to disable the immo altogether, but these ECU's are not just plug and play. Contact [email protected] parts on here, he does immo work.

The most important thing is that you confirm 110% that the original problem (O2 heater short) has been fixed, because if not, you're going to immediately let the magic smoke out of the new ECU as well.


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## runvdub (Mar 23, 2011)

So buying a used stage 1 united motorsports ECU for AWP manual transmission with immo defeat. That should be compatible correct?


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## runvdub (Mar 23, 2011)

Well this isn't factory ECU but car ran fine on it before. 









Will this ECU work to replace it?









The last two digits (DL vs RN) make a difference?


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## Slimjimmn (Apr 8, 2006)

runvdub said:


> Well this isn't factory ECU but car ran fine on it before.
> 
> 
> The last two digits (DL vs RN) make a difference?


RN - awp 
DL- aww

it should work,
just make sure the rear o2 sensor is new and or the short is fixed.


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## runvdub (Mar 23, 2011)

Perfect. And my engine is awp anyways so that's better. But o2 is brand new as of tonight.


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## dubbed-outt (May 18, 2011)

did you ever fix your problem? and what did you end up doing if so?


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## jland22 (Oct 17, 2012)

This happened to me last night only while driving. The EPC light came on and I lost a lot of power then a few miles later I lost all throttle response.

I am convinced that it is the accelerator peddle sensors/wires. There was heavy rain that drive and also had to drive through a couple large puddles (my car is lowered too). The previous owner drilled a 3/8 inch hole through the firewall for a boost gauge that is no longer hooked up so there is just an open hole for water to travel.

Right behind the firewall is all the wires to the pedals and I did notice it was wet from the looks of it. Found a replacement OEM pedal for 140 from ecs tuning however ebay has some for 60 bucks.

Going to go push the trigger and get a replacement pedal. If this does not fix it the only other alternative that makes any sense to me is the throttle body sensor.


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## Anony00GT (Mar 6, 2002)

jland22 said:


> This happened to me last night only while driving. The EPC light came on and I lost a lot of power then a few miles later I lost all throttle response.
> 
> I am convinced that it is the accelerator peddle sensors/wires. There was heavy rain that drive and also had to drive through a couple large puddles (my car is lowered too). The previous owner drilled a 3/8 inch hole through the firewall for a boost gauge that is no longer hooked up so there is just an open hole for water to travel.
> 
> ...


Before you do that, scan it and get all the codes. You can use a good scan tool (Read: VCDS) to check the pedal before buying any parts.

To call a pedal failure is rare is probably an understatement. Don't think I've ever seen one get wet though.

Either way, diagnose properly and repair once, instead of just throwing parts at the problem. You need the proper scan tool to adapt any throttle-related replacement parts anyway.


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## jland22 (Oct 17, 2012)

Anony00GT said:


> Before you do that, scan it and get all the codes. You can use a good scan tool (Read: VCDS) to check the pedal before buying any parts.
> 
> To call a pedal failure is rare is probably an understatement. Don't think I've ever seen one get wet though.
> 
> Either way, diagnose properly and repair once, instead of just throwing parts at the problem. You need the proper scan tool to adapt any throttle-related replacement parts anyway.


Thank you. I had the local VW shop run the codes:

P0222- Throttle position sensor 
P0601- Fault in the Powertrain Control Module (PCM)

The dealership said that the P0601 may be thrown due to the sensor failure in the pedals or throttle body sensors but it was most likely the pedal sensors. 

Are these codes to vague?

I am also reading that people replaced the peddle and the throttle problem still persists. Could it be the wiring in the ECM between the sensors that went out?


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## Anony00GT (Mar 6, 2002)

P codes are never great compared to a VCDS scan. 

Codes aside, you need the scan tool to test operation of all the sensors to figure out what's going on. It could be a wiring issue as well.


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## elRey (May 15, 2001)

http://forums.vwvortex.com/showthre...tion-Sensor-(G79)-P1631-35-00-Signal-too-High


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## Ivanmk4 (May 21, 2013)

*help!*

yo! i been having the engine cut off and the epc light come on too but when i read the check engine, the code was p0740 which is the TCC. so i bought the solenoid for it since its automatic. Sooooo that has NOTHING TO DO with the engine dying out when i come to a stop? For example: Im slowly pulling out of my drive way, as my car goes from 1st-2nd gear, it slips then the other gears are good. i keep driving, then randomly, as i come to a stop, my car turns off (only when im coming to a stop or am completely stopped). I keep trying to turn it on but it doesnt get the crank until i press the gas pedal like 10 times while cranking it. when it finally turns on, the EPC light stays on. then i turn it off and it turns on normally after that. Is that what you were experiencing? Because my code read p0740 which was the TCC


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