Hi all. I have a 2016 Superb 2.0TSI 206kw 4x4 (96kms on the clock) that has developed an intermittent fault that I’m struggling to resolve. Hoping that some of you with more knowledge than I have can help.

 

A few months ago, driving through town, in Sport Mode, took an uphill corner at normal speed and the EPC light came on the dashboard, and it started running rough, like it was on 3 cylinders. Pulled over. Turned engine off. Waited a few minutes, turned engine on again and it was fine. Was booked in for a service the week after, and I asked the local dealership to check for any fault codes. They advised that there was misfire error logged on cylinder 1. Suggested it might be ignition coils, but cleared the fault and advised to take it back in if it happened again. Ran normally for a month or so then out of the blue, had the same issue. In Sport mode, but normal driving, EPC light came on and stared running rough. Again, stopped, turned engine off, stared again and drove in normal mode and was fine.

Given the KMs on the car I figured that replacing the coil packs wouldn’t be a bad idea anyway, so I ordered and fitted a set of 4 Swan coils. I also ordered the ThinkDiag mini diagnostics reader, as I figured that with 3 VAG group vehicles it would be useful. After fitting the coils, I ran the ThinkDiag health scan which indicated a P030100 error (cylinder 1 misfire) and P14AC00 (exhaust door control unit mechanical malfunction). With the new coils onboard, I cleared the faults and carried on using the car again.

 

After a few weeks of normal use with no problems, yesterday evening I had the same problem. EPC light came on, started to run rough. I was in Sport mode (but this could be a red herring?). Stopped the car, left for a few minutes. Started again and all fine. Ran the ThinkDiag tool again this morning and it has logged P14AC00, P030100 and now P130A00 (Hide Cylinder - I think this means that the control unit has effectively shut down the cylinder?)

 

so, questions right now are:

 

1. Could the P14AC00 exhaust door control unit fault be related to or even the cause of the cylinder faults?

2. Having replaced the coils, should I also replace the plugs? (I did check the plugs and they looked fine, and were gapped correctly)

3. Any general advice on what next steps should be?

 

thanks all!

It’s definitely sport mode that’s causing this fault. Have driven 2000kms in normal mode over the past week, as soon as I put it in Sport mode this morning the EPC light came on and it started running rough. Turned engine off, on again, and fine for another 500kms in normal mode. Logged P14AC00 (Exhaust door mechanical control unit 2), P030300 and P030200 cylinder faults in sequence. Any advice appreciated 

At a guess, P14AC00 is probably related to the exhaust flaps being stuck or obstructed?

 

Not sure if that would cause the other codes

Was the most basic of checks done after the fault codes were read.  Ie the spark plugs removed and inspected and replaced if required.  That would be before replacing any ignition coils which might prematurely reach end of life because of overheating spark plugs.?    EDIT. Sorry missed point 2 reading on phone .  You really need to inspect the plugs very closely.  They are overdue the VW group recommendation on replacement. 

Edited 13 July, 20214 yr by e-Roottoot

Hi again everyone. Thanks for the replies. A further update to this. I took the Superb back to the local service agent after continuing to experience the ECP/Sport Mode issue. They inspected the plugs and decided to replace them as they were showing signs or arcing. So I now have new coil packs and new plugs. They confirmed that one of the exhaust flaps is stuck in the open position and needs to be replaced. Unfortunately, they are hard to find here in NZ, so still looking, but the garage advised that as it is stuck open (rather than closed) it shouldn't be an issue. However, even now with new coils, new plugs etc. occasionally, if I put the car in Sport Mode, the ECP light comes on and it drops a cylinder. Same symptoms as before. Restart the engine and it's fine. Logs a P030300 or P030200 fault. The local dealer seems a bit stumped as to what to do next.....

I've had these errors come up this morning as I tried to start up this morning! I am stumped as the Coilpacks and Sparkplugs are failry new and have done a maximum of 2500 miles. I swapped the coilpacks and took out the plugs cleaned them and swapped them around aswell, good thing is that it started however as i drove it round the corner it started misfiring again.  

 

I'm hoping at worst it could be an injector or 2.

 

 

On 13/07/2021 at 09:41, langers2k said:

At a guess, P14AC00 is probably related to the exhaust flaps being stuck or obstructed?

 

Not sure if that would cause the other codes

It my be worth using vcds to code the flaps open to see if this makes a difference.

Failing that, remove the springs from the flap motors on the mufflers whilst the flaps are open. This wont cost a dime in the search for answers.....

3 hours ago, Awesam said:

I've had these errors come up this morning as I tried to start up this morning! I am stumped as the Coilpacks and Sparkplugs are failry new and have done a maximum of 2500 miles. I swapped the coilpacks and took out the plugs cleaned them and swapped them around aswell, good thing is that it started however as i drove it round the corner it started misfiring again.  

 

I'm hoping at worst it could be an injector or 2.

 

 

Overboosting perhaps??

3 hours ago, Bigeater said:

Overboosting perhaps??

 

This is from a cold start and whilst idling or try too! 

Me again. Still haven’t got any further with this and the local service agent seems stumped.

 

I’ve disconnected the connectors on both of the exhaust flaps and they are now permanently in the open position. It throws an error code about an open circuit but at least both flaps are always in the same position now. To be clear, I think this is entirely related to the EPC issues though.

 

I’m still getting the same problem, whereby when I put the car in Sport Mode, the EPC light comes on and it starts running rough. Turn engine off, then back on again and it’s fine. Have attached screenshot of the fault codes. Nobody seems to know what to do next. Have new coils and new plugs already. 

Edit post above, I think the exhaust flap issue is entirely UNRELATED to the EPC issue

Exhaust flaps are gonna be unrelated.

 

what’s the mileage? I’m wondering if the manifold and Intake tracks are coked up with carbon a bit 

That's what I was just thinking!

Maybe get a a bores cope camera scan done to check the state of the cylinders/pistons. 

 

Also have you done any modifications? 

Edited 20 November, 20214 yr by Awesam

Thanks @ApertureSand @Awesam. 106,000kms (so 66,000 miles) on the car. It’s in for a service in a week so I’ll ask them to scope the manifold etc. Great suggestions

Hello again. Updating this thread for completeness and for anyone else with similar issues (although the problem still hasn’t been solved….)

 

I had a manifold Carbon clean and injector ultrasonic clean done a few weeks ago. The garage said that it wasn’t too bad, but was worth doing, and there’s a noticeable improvement in acceleration. It feels a lot more ‘nimble’ and more like it did when it was new. 
 

Unfortunately, I still have the ‘sport mode/EPC issue’ 😞. To recap, if I put the car in Sport mode, within a few minutes the car shows an EPC light and a solid engine warning light. I pull over, turn off the ignition, turn it on again in normal mode and it’s fine. Only ever happens in sport mode and is resolved by ‘turning it off and on again’. All

other symptoms and fault codes are as above.

 

so frustrating!

 

 

I had quite an interesting journey over the last few months in terms things need fixing to my car.

So I think it could be your high pressure fuel pump beginning to seize as I had an Autotech one seize up after 6 month and had to buy a new one. 

I had a similar issue, once in the road and the other on a dyno, where the car would make the power and the epc light began to flash and was fine if you switched off and on again. 

Or could be the crankshaft sensor

I'm thinking that the exhaust flaps only open in Sport mode so they are linked somehow, perhaps the flap motors run off the same supply as the coils or injectors and cause the misfire faults when they open or close. If you disconnect the flaps, can you drive in Sport mode without misfire faults? Do you ever see the faults when not in Sport mode?

Thanks @D402 

 

The fault only ever occurs in sport mode. I had discounted the exhaust flaps but have had a niggling feeling that they may be related somehow.

 

I currently have both flaps disconnected, but only by unplugging the flap servos, which is throwing an error code.

 

I guess I either try and disable them in VCDS or something similar, or I try and find a replacement part for the servo that’s faulty.

This is the part I need to replace, but I’m struggling to find anywhere

4N0133246 - Exhaust Control Valve Actuator - Genuine Volkswagen Part (vw.com)

 

Genuine AUDI VW SKODA SEAT A1 A3 Cabriolet Servomotor 4N0133246 | eBay

 

SERVOMOTOR FOR EXHAUST FL | Introcar

Edited 7 January, 20224 yr by Awesam

I’d scoff at paying that for those. Why not remove the springs inside each unit and connect them back up to see if the motors are trying to run. Without the springs in, the motors will run for 3 or 4 minutes after the car has been locked, but it will prove a point because you can hear them trying to open and shut.

Btw, I’ve replaced my back boxes and am running without flaps. The wires are just bagged and tied up out the way, and I’ve not had any warning lights come on in the 5 months it’s been like that. Hope this helps.

Edited 7 January, 20224 yr by Bigeater

6 hours ago, Bigeater said:

I’d scoff at paying that for those. Why not remove the springs inside each unit and connect them back up to see if the motors are trying to run. Without the springs in, the motors will run for 3 or 4 minutes after the car has been locked, but it will prove a point because you can hear them trying to open and shut.

Btw, I’ve replaced my back boxes and am running without flaps. The wires are just bagged and tied up out the way, and I’ve not had any warning lights come on in the 5 months it’s been like that. Hope this helps.

Thanks for that @Bigeater

I currently have both servo motors disconnected and bagged up like yours, with the flaps in the open position. Prior to doing this, the faulty side would, as you say, keep running for 3-4 minutes after the car had been locked. I get what you mean though, trying it without the springs, which would isolate the servo from the flap mechanism, and I will test that for sure.

 

Interesting that you’ve had no fault codes logged. With my servos disconnected I get P301900 and P302300 faults logged.

Well I found the problem with the exhaust flaps at least (see attached image). The actuator spring is broken, which obviously explains why it wasn’t working! I can’t find the spring on its own to buy, so I’ll try tack welding it first, and if that fails I’ll buy a replacement actuator from overseas (I’m in NZ and it’s very hard to get parts here). So that helps understand the exhaust flap issue. Whether it’s at all related to the EPC issue who knows…..

Another update on this. I ordered replacement springs for the exhaust actuators from a US based website. Once fitted, the exhaust actuators are now working perfectly and the P14AC00 fault is now not being logged. Unfortunately, I’m still stuck with the ‘Sport mode/EPC’ issue. As a recap:

 

- when in sport mode, EPC light comes on and engine runs ‘rough’

- logs various cylinder related faults

- turning the engine off, then back on again returns it to normal operation

- so far, I have replaced coils, plugs and had the exhaust manifold blast cleaned

 

Any further ideas appreciated!

6 hours ago, revirdnhoj said:

Another update on this. I ordered replacement springs for the exhaust actuators from a US based website. Once fitted, the exhaust actuators are now working perfectly and the P14AC00 fault is now not being logged. Unfortunately, I’m still stuck with the ‘Sport mode/EPC’ issue. As a recap:

 

- when in sport mode, EPC light comes on and engine runs ‘rough’

- logs various cylinder related faults

- turning the engine off, then back on again returns it to normal operation

- so far, I have replaced coils, plugs and had the exhaust manifold blast cleaned

 

Any further ideas appreciated!

Did you try a new set of cables?