Skoda Superb 2017 Diesel model. Occasionally the car runs some sort of cleaning cycle (DPF?) when parked - loud noise for a few minutes and then stops. But sometimes (last night for example) the cleaning cycle will kick in and run until the battery drains - around an hour or so, requiring a jump start. Worryingly I'm getting to know our local AA battery tech too well - he's not seen this kind of problem before on any of the other Skoda or Euro diesels he supports.

 

We've had the garage run diagnostics but it all comes up clean. 

 

Just wondering if anyone else has had this problem with a non-stop cleaning cycle and what the fix was?

DPF Regeneration cycle I think is the correct term

Hi there.

Although I cannot comment about the Battery drain. Could I/we please ask..

 

1) What sort of Mileage you do daily/weekly? Are they Short, around trips or longer A road/Motorway blasts?

2) Can you can recall how frequently the DPF regens are taking place?

3) When your garage ran diagnostics did they report back on what the DPF Soot levels were/ are?

 

This looks like a related issue from many years ago, although we cannot see what the resolution was

 

 

Thanks

Just to be clear, the fun starts after a drive?

 

Some people have had issues where the car hasn’t been driven and the fan starts by itself or at least not been driven for some hours, if it’s this then it’s likely to be dodgy relay.

 

If it’s not that then if it does it again, start the car again and go for a drive on the motorway in 3rd or 4th for 15 minutes which should complete the job properly

Another thing to add about the regen process:  The fan running after you stop is to cool things down.  It is NOT the regen itself taking place.  Just a sign that a regen either has just finish or (more commonly) that a regen has not finished.  The process requires the exhaust temps to be raised by 2-300 degrees (maybe, This is an educated guess at this point without looking it up).  This extra heat needs to be dissipated.  If the regen is not complete when you stop, then the fan needs to run to cool things down again before you start the car up for the next trip.  Then if you don't drive for long enough for the regen to complete next time the fan will again cool things down when you stop.

 

First fix: go for a nice long drive to make sure the regen is completed.  This should also have the knock on effect of giving the battery a charge.

Second fix: Have a think about how old the battery is.  If the original part then 7 years on a stop start car is time for a new one.  just make sure it's coded so the car knows to charge it like a new one.

Third fix: Maybe the DPF has had enough and needs a clean or even replacement.

Worth to pay a visit to decent diagnostic service.

Thank you for the suggestions and questions: 

 

1) Mainly used for daily commuting - about 30 km/day, often in stop/start traffic with auto-engine off operating. I also favour driving in eco-mode so generally low revving. Used to be used a lot on the weekend but less so now.

2) Regen maybe once a week - usually fan just on for a few minutes

3) Soot levels unknown but garage believed ( at least service) DPF was OK - have another service coming up soon so will get that checked.

4) Yes, Happens after driving (although I do seem to remember a few times the fan tuned on a few hours after driving)

5) Just put new battery in after last incident a few days ago. Existing battery was between 1 =-2 years old.

6) Might be relevant, one time the drain happened was after a long day driving along a very rutted and dusty road - fan noise came on and stayed on fora long time until battery drained. Garage checked diagnostics but nothing found and drove the car around for a few days themselves but incident didn't reoccur.

 

When the battery does drain, the fan seems to come on a LOT louder than normal for that cycle, but that could just be me remembering 2 specific incidents when it happened.

You don't need a diesel car. More to that I suggest to change your preferred garage as the current one seems to be unable to perform a proper diagnostic. Diagnostic does not end with fault code reading. 

Quite apart from the low weekly mileage causing extra DPF regens - I'd suggest getting the coolant fan thermostats tested for correct temperature operating range.

If the fan is on after the car is running, that does not indicate the regen has completed. Please see my post above. Seeing that behaviour once a week doesn't necessarily mean a regen once a week.

Also, fan on for just a few minutes might point to the system not actually being that hot so lots of cooling is not required.  If the regen has completed, the fan should not run at all unless you are in particularly hot climate.

30km a day is roughly the same as mine (10 miles each way) and one of the main reasons I dropped my diesel.

1-2 years for a battery is far too short. If the garage is suggesting that then there is another issue with the car making the batteries fail so soon.  You need to find out what is causing the issue. Could be the fan random running thing combined with fan running too much due to not completing a regen.