2018 Fabia 1.0 TSI 110PS, 24K miles.

Wife came home this afternoon and reported amber EPC light on, which resets when engine is shut down then restarted. 

Went out to check, EPC lights up on switch-on, extinguishes on engine start - so far, so good; started engine, no warning light but EPC warning lit up immediately when engine throttled-up in neutral, light resets if engine shut down then restarted.

Took it for a test drive, MIL and EPC lights both came up straight away, engine appears to be running completely normally, no misfires.

I have not plugged in OBD reader for DTCs yet - will do that tomorrow if weather permits.

Car is booked in for diagnostic on Friday, I'm thinking faulty MAF sensor might be a possibility - but does anyone have thoughts on possible causes?   

 

 

Edited 27 January, 20251 yr by Warrior193
repetition

Is yours just a reader or fuller scan tool?

 

Have you done the driver/owner checks yet?

 

Any work done on the car recently, or elbows in engine bay?

 

Without codes and better still live data there are so many possibilities.

 

16 minutes ago, Warrior193 said:

but EPC warning lit up immediately when engine throttled-up in neutral

Might even be something as simple as a quick spray of GT85 around the throttle pedal.

 

I'll take it that it is fully and properly serviced and maintained in a timely manner - and that the battery is in a good state of charge.  😄

 

There been a few threads on 2018s but not these two lights IIRC(?) more issues with 2019 cars IIRC(?).

 

See what tomorrow brings.  Good luck.  I know these things have to be sorted ASAP as a distress call from the Boss means immediate attention and attendance usually at most inconvenient times but saying so only makes matters worse. 🫠

 

As above, guessing is for silly people, if I was silly I'd suggest "Throttle Body issues" - quite fashionable for later cars than your wife's one  - but until you have checked for logged faults, many simpler/cheaper things are possible,

 

Probably no MAF sensors in these engines.

Edited 28 January, 20251 yr by rum4mo

Scan tool is Autophix OM126P. Can do live data.

1 x DTC logged (twice) is P003A - turbocharger boost control A position exceeded learning limit.

No other DTCs logged. I haven't cleared the fault yet, as it is in for a diagnostic check on Friday.

 

No recent work under hood, apart from usual oil and fluid checks since oil service last June.

 

Battery is original EFB and standing voltage is a little over 70% (12.35V) vehicle has not done much running since Christmas - although I wouldn't expect the smart alternator to maintain charge level much higher than it is.  

Edited 28 January, 20251 yr by Warrior193
added information

Had a look at a pretty good video for the Autophix OM126P, it  showed it for American IM readiness, looks like you get a lot for around £30 and nicely designed, one vid had you get free lifetime updates I don't know if that applies to UK or not, freeze frame and live data will be useful. - https://www.youtube.com/watch?v=SsfvtdCTukk

 

Usual advice with code reader make sure it is fully updated before you plug it in.  The limits might be that this is a generic code but the vehicle has also registered an issue by throwing up a couple of warning lights.

 

P003A -

"What Does the Engine Code P003A Mean?

Character "P" in the first position of Diagnostic Trouble Code (DTC) represents the powertrain system (engine and transmission), "0" in the second position means that this is a generic OBD-II (OBD2) DTC. "0" in the third character position in a DTC indicates that the fuel and air metering and auxiliary emission controls is experiencing a malfunction.  The last two characters "3A" is DTC number. OBD2 Diagnostic Trouble Code P003A means that Turbocharger/Supercharger Boost Control 'A' Position Exceeded Learning Limit has been detected.

How Serious Is the Code P003A?

This issue is critical and can lead to damages in your car.  Please clear it first, drive your car for a couple of days. If the issue reappears,  Carly recommends to fix your car to resolve this issue." - https://www.mycarly.com/obd-codes/p003a-turbochargersupercharger-boost-control-'a'-position-exceeded-learning-limit/

 

Have you driven the car and put it under a bit of load say going up a hill or pushing the turbo with higher revs in a gear higher than you should be in to see if it's under performing?  Car running well  being a VW always makes me think of potentially computer brain-farts and perhaps electric, wires, connectors etc..  Did you delete the error code after the old off-'n'-on-agen failed?  A higher level scan tool might give more info and detail. - https://www.youtube.com/watch?v=LCDvnHKM6m0

 

 

8 hours ago, Warrior193 said:

Battery is original EFB and standing voltage is a little over 70% (12.35V) vehicle has not done much running since Christmas - although I wouldn't expect the smart alternator to maintain charge level much higher than it is.

The alternator can't do much if the car's not running, 70% /12.35v isn't low (particularly if you go with the 12.4v / 80% but why not fully charge the battery to 100% with an appropriate battery charger maintainer following the instructions for the car in the Owner's Manual and for the battery charger maintainer and recharge at a lower rate (of amps) over a longer time as possible.  When the car has an issue(s) it's best to have the battery in the best state of charge possibly, particularly if the issue involves computer, electrics, engine starting as this can help with diagnostics and repairs whereas a low state of charge can hinder diagnostics and repairs.  (I know you know this, put for other readers.) 

 

ETA: IIRC(?) throttle body issues were generally with 2019 cars

 

Edited 28 January, 20251 yr by nta16
spelling

Bother, "turbocharger boost control" seems to be another "fashionable" issue to befall the 1.0TSI engines, no good guessing though as to what exactly is causing this.

VW 3-pot engine, take it to 110PS and it might need more attention given to it than most average drivers/owners would know or bother about for longevity but Warrior193 isn't the average driver/owners judging by all his posts here, Mrs.Warrior193 might be an entirely different matter but if she's anything like my better half then she'd expect her partner to sort the car for her to just drive so things would be kept in order, or as much as allowed.

 

Regardless of if there's a problem now and what it is as soon as the car was out of its (minimal) 3-year warranty if it is to be kept for any good length of time to have the engine "serviced" perhaps more frequently and using better oil than a Dealership or most garages/mechanics would particularly if the car isn't used enough.

 

Update, cleared the P003A fault code and took it out for a hot run (not saying where, Officer 😇)  EPC and MIL light stayed off on a full-throttle run, taking it to the red line through the gears for 17 miles after getting oil up to 90*.

Then took it up a hill, redlining in 2nd - ditto. Turned-off into a side-turning for return home and the EPC lit up as I was doing 3-point turn! - no MIL light. Cleared fault and drove a mile towards home, EPC came up again when I did a hard accelerate in 2nd. 

A second, slower run a little later gave real time monitoring boost pressure of 220kpa absolute on hard throttle in lower gears (approx. 99kpa static, therefore about 1.2 bar boost) can anyone tell if this figure is in the ballpark?

VAG data for the CHZC appears to imply that the turbo is not variable-vane type - can anyone confirm this is correct?  

Edited 29 January, 20251 yr by Warrior193
added information

20 hours ago, rum4mo said:

Bother, "turbocharger boost control" seems to be another "fashionable" issue to befall the 1.0TSI engines, no good guessing though as to what exactly is causing this.

I was hoping that someone here had experienced this fault and found an easy/cheap fix for it.

The old Italian tune-up, though I was more thinking of hassling the turbo and engine with pushing it in too higher gear with lower revs, enough to get the turbo turning of course but engine having a bit of labour rather than big blow out.

 

Sorry idea about turbo figures, and they're in metric, I've only got inches on my rulers. 😁

 

What about trying a thread in 'General Maintenance' or 'Diagnostics & VCDS' for different posters.

 

Good luck.

 

It seems like using Google can show you some info - well that usually works to connect you with some useful stuff and some not quite so useful - that was just a general statement as I've found the "search" function in most car forums are very very picky and so yield zip all.

I finally found a VAG data sheet that gives a figure of 1.6 bar (160kpa) relative boost for the 1.0TSI 110PS.

Still searching for turbo details, but as the charge pressure is controlled by an electronic bypass flap, it suggests to me that the turbo vanes aren't variable.  

Happy to supply any info pertaining to the car that I can look up for you, just message me with VIN or reg. 

Update 2. Garage could find no obvious cause of fault after diagnostic check, car remained fault free for 3 weeks since the check - until yesterday - EPC lit up again while wife was returning home.

I plugged OBD11 reader in - no DTCs recorded, EPC extinguished when engine started.

I took it out for test, EPC and MIL lit up and engine appeared to go into limp mode as soon as I accelerated onto A3. DTC P003A again!

Question, wife needs to use car before the garage can take another look - should I leave DTC logged so mechanic can see that the fault was definitely recorded - or should I clear the fault before she drives it again?

I'd say leave any/all logged faults, and maybe even save/print them off just in case the controller clears them with time - as seems to be the way it is with some logged faults in "newer" VW Group cars.

I think you have to leave the error code in as they won't believe you or your scan tool or read out.

Certainly true for in the distant past, I got some sarcastic reply when explaining some faults that I noted on a 2002 Polo while under warranty, a different experience when reporting logged faults on a 2015 Polo while under warranty - maybe all the old duffers had retired by then so younger techs were open to listen to a VCDS user and car owner.

Yes you should always take note of what the customer tells you but always check for yourself to confirm, no matter who tells you.

Update 3, Fabia into garage this morning. When I scanned for faults last week, there was just one DTC - P003A, garage called me to say the DTC now recorded is P334B00 - Charge pressure actuator position sensor - which fault appears to be fairly widely reported and, I understand, there has been a TPI issued by VAG.

Waiting on results of further investigation.

Bit of a downer.

This might have shown up the limitation of you code reader, or the problem or code might have not shown previously anyway.

I think charge pressure actuator position has been in threads on here before.

Depends what's in the TPI, no doubt you've seen lots of info on this issue, doesn't sound like it might just be the arm or pivot points to be a simple clean and lube job (and not sure you can really lubricate other than a quick spray of GT85). I have seen actuator upgrades for soup'd-up cars with I think stronger spring(?).

If you've not seen this thread a poster is on to one track, which might be very common. - Tut, sorry I can't find it now but you've probably seen his posts on a VW forum about seized actuator arm (IIRC) and there being a TPI.

Good luck.

Edited 12 March, 20251 yr by nta16
typos

Received an update call from the garage this morning, turbo flap actuator is OK - the issue is sticky/tight actuator arm.

A repair kit is available and has been ordered (£40) - no information available if the kit is a revision, but a possibility.

Yes I think that's the common cause. You'd hope as it's a repair kit rather than just replacement part (or a part of a part perhaps) that it is a revision and upgrade. So much for German engineering quality. 😁

Be interesting to see what you get for forty quid and how much the diagnosis and repair charges will be/are.

Hopefully that'll be the end of it for at least a very long time if not beyond your ownership of the car.

Good luck.

Edited 12 March, 20251 yr by nta16

Repair completed, picked up Fabia this morning. Fault was P334B00 - charge pressure actuator, mechanical malfunction.

SWMBO is very pleased to have her car back.

The cause of the fault was found to be excessive resistance to movement of the turbo boost flap control arm.

The part replaced was Turbo actuator coupling rod, repair kit 04C-198-701-D.

Assuming the following is correct, sourced from Cox Motor Parts - https://www.coxmotorparts.co.uk/product/seat-shop/seat-arona/arona-2017/arona-2017-engine/genuine-vw-seat-audi-skoda-turbo-actuator-coupling-rod-repair-kit-04c198701d/

Genuine VW/Seat/Audi/Skoda Turbo Actuator Coupling Rod Repair Kit (04C198701D) - £38.82

(ETA: it's probably described as a kit as it includes the clips shown 😄 )

Edited 18 March, 20251 yr by nta16
ETA:

in a way, it is good to see that a repair kit has been developed, as opposed to the usual "change the lot", ie selling and fitting an improved turbo assembly.