cruise control

[partyanimalcars]

hi there i have a 2012 skoda superb elegance 4x4 this a great i got this in december2021 with 18000 on the clock i know super low mileage only done 26000 now this has been great and still is but i noticed something the other day when i was in 6 gear manual box and selected cruise control i pressed the up toggle switch and speed climbed to about 58 mph then it dropped cruise out now its never done that before so i did it again and it did same thing, so today i tried it in 3rd gear no problem and then 4th gear same thing ok then 5th all ok then 6th no joy soon as i raise speed to 58mph drops out so i wonder has anyone come across this problem the cars only done 26000 miles i would not thought i would have any problem yet

[DrCorbyLee]

Is this a diesel? I'm wondering if you're stuck in DPF regeneration which won't allow the car to hold the higher gear whilst it's trying maximise heat input for best DPF regen' efficiency?  On my own car (DSG), a sure sign a regen' is active is when the car won't stay in 5th when pootling around town with cruise set at 30mph.  With the DSG it simply drops you straight back to 4th soon as 5th is selected but cruise stays on at same set speed. Obviously a manual can't do that so maybe response is to drop you out of cruise.  If that's correct and this is happening repeatedly, it sounds like your car could have blocked DPF and is constantly regenerating.  I'd certainly be worried about the state of DPF on an 11 year old car that's only done 26K as unless the 40 miles per week average before your ownership were just from occasional long runs, it does sound like the car has maybe done lots of short journeys which are not good for a DPF equipped diesel.  My own car is a year younger but has covered 126K with the majority long motorway cruises which is ideal for keeping DPF healthy although even mine is predicted to have problems just after 155K when the Oil Ash Residue (essentially the crap that doesn't burn off in a regen') will reach the theoretical loading limit for the DPF.

 

Even if DPF regen isn't the cause of the cruise problem, I'd consider investing in the means to keep an eye on the DPF.  Cheapest solution is an android app called VAG DPF which is a couple of quid from recollection (and there's a free version with limited functionality to try first so you can be 100% sure it works with your engine variant) although also needs hardware to plug it the OBD port.  Cheapest "approved" hardware solution for that is the Carista dongle which also has its own diagnostic software included which, whilst isn't as powerful as VCDS, is still useful.  VAG DPF allows you to monitor and log a myriad of parameters associated with the DPF and you soon get a feel for the performance of the DPF and learn the signs for when it's in a regen even without VAG DPF running.  That's useful as means you can often prevent interrupted regen's simply by going once round the block rather than immediately parking at your destination.

[partyanimalcars]

hi thanx for your input yes it is diesel it could be something to do with dpf regen i suppose but a little bit of history of car i bought this in december 2021 with 18000 miles and when i checked it had been off the road for 4 years think its cat n according to mot history its only had 4 mots i think because its been sitting in a barn  somewhere but its immaculate now so its a diesel superb elegance 4x4 so i tried it in 3rd no problem 4th the same 5th the same and even in 6th you can hold cruise at any speed exept about 58 mph now i havent tried driving at 58mph and then press toggle on cc to hold speed but i suspect it would be ok  i will replicate that senario so bit perplexed why it does not like to continue past 58 without dropping out if you think its something to do with dpf on my last car bmw 530d that had dpf problems from right when i bought it out of the garage but there was no lack of performance so within time i found the answer was to use  bmw code reader and when i checked the exhaust back pressure i found it to be 40 psi and it should have no been anywhere near  so i bought some dpf cleaner  to put tube in and filled pipe off back pressure sensor and voila pressure went down to 2psi  hence no more dpf related issues. so is there similar on skoda that i could use the same method to give it a clean out thanx for your time

[DrCorbyLee]

Even allowing for that period off the road that is still a pretty low annual mileage for a DPF Diesel.  Before you go to trouble of looking at cleaning DPF, I'd think about sorting access to VAG DPF so you can see exactly the status of the DPF:

 

 

Unfortunately, when I just checked Carista has gone up considerably since I got mine 4 years ago when I knew was going to be keeping my car and started to worry about DPF life.  Was £10.99 on Amazon back then, now gone up to £34.99, damn COVID / Brexit / war in Ukraine / anything else manufacturers use as an excuse to make extortionate price increases!  Less than 40 quid including the paid for version of VAG DPF is still a reasonable investment to put your mind at rest regarding current state of the DPF and if nothing else, the month free trial of the full version of the Carista software might also be useful to be monitoring for fault codes when this dropping out of cruise in 6th happens