EPC Light after service, including plugs and coil packs

[Tiny1138]

Hi
Mk7 GTI DSG. Car in for for a service nearly 2 weeks ago.

Included 4 new APR coil packs as they found the rubber was splitting on one coil, so replaced all, also changed the plugs (NGK’s).

Driving normally everything fine but now getting intermittent EPC light and limp mode when using Sport or manually through the gears when pushing on.
Pull over, ignition off and on and it clears. Absolutely no rough running or misfire.

Serviced every 10k and at least an oil and filter every 5/6k.

looking through the forum can see this seems to be a common thing but no definitive answers.

Has been running Stage 1 by a very reputable tuner for the last 18 months and 33k with zero issues.

Any ideas from people in the know or those who’ve experienced the same?

 

[StorableComa]

Sounds like a misfire or other issue that resets when the ignition is cycled. Is it high RPM that these happen?

Best way to tell is to read the codes. Do you have a code reader?

 

[Tiny1138]

Hi
Yeh is high RPM when it happens, driving normally absolutely fine.
I don’t have a code reader I’m afraid, appreciate that doesn’t help things much on here!

 

[Diggs24]

CAN'T HELP WITH NO CODES.

 

[StorableComa]

My money would be on misfires if it's high RPM, but that's worthless without codes. See if you can borrow a code reader, or if a local shop is willing to do a reading. The codes will be stored, and should point quickly to the issue.

 

[Tiny1138]

Will do cheers, I’ll report back once I’ve got them

 

[greggles]

33k miles total on a 2015, or the last 33k miles problem free? With the investment you just put into the coils, I'd pick up an obdeleven tool so you can read codes and figure out issues on your own. Given that the coils were just replaced, its probably a misfire, which you would first swap coils on to diagnose, (if misfire moved, it was the coil), if coils fine, plugs (maybe gaps). Most tuners have a recommended plug gap, don't know if you set them when you changed the plugs.

If coils, and plugs are fine, then its probably something wonky (whole host of things) or injectors, carbon buildup.

 

[Tiny1138]

Sorry - 33k since tune. Now on 52k. Appreciate all the guidance. As I say I’ve had absolutely no problems until now after the service.
I’ve ordered an OBD Eleven so hopefully have the codes up soon

 

[greggles]

Once you can read the codes, you can see which cylinder is causing the issue. It's probably cylinder 2 though.

Things to try after moving the coil and verifying its fine, and verifying the plugs are fine. (checking gap per tuner recommendation). Run a can of seafoam through the tank. If problem goes away, you had an injector that needed some cleaning. If not, you are down to carbon build up, or some sort of fueling issue (most likely still an injector). I think most of us just do both at the same time, since everything is already off at the shop to do the carbon cleaning.

 

[Tiny1138]

Ok so I managed to get the fault to appear just now by giving a few harder pulls. On about the 5th attempt of trying the EPC light came on and again went into a protection mode limiting to 4000 RPM.
pulled over to get the OBD II reader in once ignition was off, went through the process and shows ‘no codes’. Tried rescanning several times but still nothing.
the EPC has now gone out after recycling ignition.

 

[Tiny1138]

I think you can get into a world of thinking something doesn’t ‘feel quite right’ but I don’t think it’s pulling as hard as it was (bearing in mind I want to take it easier having this issue)
Could it just be down to bad fuel? I filled up the other day at the nearest petrol station (ESSO) and filled up with their ‘99+’ (my stage 1 map needs to be ran on 99)
This was the first time I ever used their 99. I’m just wandering if it could be that?

 

[jimlloyd40]

I think you can get into a world of thinking something doesn’t ‘feel quite right’ but I don’t think it’s pulling as hard as it was (bearing in mind I want to take it easier having this issue)
Could it just be down to bad fuel? I filled up the other day at the nearest petrol station (ESSO) and filled up with their ‘99+’ (my stage 1 map needs to be ran on 99)
This was the first time I ever used their 99. I’m just wandering if it could be that?

It could be many things because the reason for getting an EPC light has so many possible causes.
https://mechanicbase.com/engine/epc-light/

 

[greggles]

question: Are you using a borrowed OBD II reader, or are you using an OBDeleven? You should have some sort of pending code if not an active code.

 

[Tiny1138]

Hi. No it’s just a simple OBDII reader, I couldn’t get hold of an Eleven. I ran the tank to completely empty and filled again with my usual Shell 99 and is still doing it. Drove this morning for about 8 miles, did 6 or 7 pulls in D mode up to 60MPH. No lights. Then once at end of my journey (oil temp at 88C) did a pull to 60MPH, steady at 60, and no more than 10 seconds later EPC and limp mode. Pull over, recycle ignition and fault clears. Again the reader discovers no fault codes. This afternoon driving slowly through town it came on again to the point where I have to be driving like a nun for it not to come on. Booked in for diagnostics on 10th Jan

 

[Tiny1138]

To add, I think it has to be something to do with once the engine is at temperature