steveja2

Hi guys ! Andy - if you have a mechanic with relevant diagnostic software telling you that all is OK then it probably is... After I blew up my sensor and reconnected everything that I had disconnected, the only fault which returns all the time is "air quality sensor open circuit" - so I guess if yours was trashed you would probably be getting a similar error. Yup - apologies for any confusion - you were correct in pointing out that I missed a 9 from the part number -I've ordered myself a second hand one from ebay just to try and keep the fault codes away (I don't think the air quality sensor works very well anyway !). So I don't really care if it works as long as it doesn't fault or set my car on fire ! (at least now if my Fuse #4 blows I know the FIRST place I will be looking !) Sorry I cant help with the black cover part number - but I would heartily recommend you have one (or at least SOMETHING to help prevent water ingress - even if its a load of black gaffa tape !)

Sorry (again !) - just discovered that there was a second page to these posts ! I HAVE TO EMPHASIZE FURTHER THE IMPORTANCE OF WHAT lowedb and vborovic said earlier. FUSES ARE THERE FOR A REASON, AND THAT IS USUALLY TO PROTECT THE WIRING NOT NECESSARILY THE DEVICE ON THE END OF IT. That is why I replaced the fuse with its original 5 amp rating. They are absolutely 100% correct in pointing out that you should NEVER simply increase a fuse rating because the original blows. I am a qualified industrial electrician and was indeed anticipating seeing the magic smoke released from some part of the car (and was prepared with fire extinguishers if it came to the worst !) I had the fuse in place for about 1 second and I was lucky... it highlighted my problem without causing other catastrophes ! I do NOT condone increasing the fuse rating (in ANYTHING !) it never ends well ! What I did could have led to a disastrous melting of cables buried deep inside the loom, could have led to shorting other more powerful cables to ground and indeed a fire or battery explosion ! So "DONT TRY THIS AT HOME KIDS !" I was lucky - and am grateful to everyone for their input. Regards, Steve

Sorry.... One last note on this topic.... After I blew up the air quality sensor (which allowed everything else to function properly again) - I decided to check the resistance on the load-side of the fuse and it has gone from 5 ohms up to 800-900 ohms ! Which looks better to me ! That seems much more like what I'd expect. So with that in mind, I replaced the fuse with a 5 amp as it was originally, and all is well ! Steve

OK final update on the issue of the blowing fuse... After bumping up the rating of fuse F4 from 5 amp to 10 amp I heard the sizzle *POP* of something burning out in the engine bay. But afterwards everything appeared to work fine !! But I was convinced that something had burnt out (am familiar to the smell of burnt out motors etc) I ran vcds, cleared all faults and only 1 returned... "Air quality sensor OPEN or SHORT circuit". Went on a mission to find location of the air quality sensor - am pleased to say I did indeed find it and it was definitely burnt out ! So for the benefit of anyone coming across this post due to similar symptoms, here is what the trouble was for me... I suspect that a previous post from someone saying he fitted a bigger fuse and the problem went away was probably similar issue - but under normal driving conditions you would never even notice if the air quality sensor was working or not (they're a bit rubbish at what they do anyway !) My short was caused by the air quality sensor - Part number 1k007659 It is located under the black plastic cover which is at the bottom of the windshield (the guard which covers the window wiper motors). It is on the PASSENGER side of the vehicle - thankfully that half of the cover simply pulls off without having to remove wiper blades. Under there is another black cover held on with 2 torx screws (this covers up the main air intake into the cabin) The sensor is clipped to the side of the air intake box with a steel folded clip which has barbs on it to grip the plastic. The sensor is connected via a 3 wire plug. Hopefully there should be some pics below showing the location of sensor and how it was burnt across its pins.... Location of sensor - right hand side of engine bay right up near windscreen... in bottom left corner of that grille... Sensor is near bottom left hand corner of the grille clipped to plastic. . The connector to my sensor showing evidence of burning... The sensor itself showing the melted plastic around the connection pins (one pin was very wobbly - almost falling out) It also smelled like burnt out motor. I am pleased to have found this and hope it helps other people. Looking back at the posts I realise that this is all thanks to Wino and a666andy who suggested upping the fuse rating. (Which led to the distinct "snap, crackle, *POP* followed by a burning smell !) NOTE TO Andy..... It might be worth checking your air quality sensor, if you situation is like mine, then upping the amperage of the fuse might have simply burnt out the sensor completely thus allowing the other devices to function correctly... Not that it really matters if the air quality sensor is not working ! Many thanks to everyone ! Forums and Professor Google have saved me 100's of pounds by avoiding paying out for hours of electrical fault finding (and I've learned more about my car in the process) Do Haynes not make a manual for the Skoda Superb !>!??

Yes I did wonder if bumping up the current like that cleared the fault.... Update: So I've plugged pretty much all the connectors back in, The air con and blower etc are working OK ! YAY ! (can take the family on holiday now without 2 hot kids whinging all the way about the heat !) The only thing I seem to have outstanding is an "AIRBAG ERROR" warning and the airbag symbol on the dash... am hoping that it might just be a connector I've missed or maybe it needs resetting with VCDS since I removed the glovebox and disconnected the airbag keyswitch. Given time I will fire up VCDS and clear the errors and check for any outstanding issues.... I might also try a 5 amp fuse back in to see if it pops (I haven't done it yet but I will measure the resistance on the outgoing load side of the fuse to see if its still 5 ohms or if has indeed blown the fault away ) At least now if VCDS flags something up specific like ABS SENSOR on Nearside Front OPEN CIRCUIT then at least I will know where to look ! PS = Thanks guys for the assistance and advice ! I will share any further findings in the hope that it may help others. Steve

Well this is interesting... Due to an earlier post suggesting that a comment was made to UP the fuse rating from 5 amp to 7.5 amp I decided to give that a go - but I didn't have any 7.5a only 10a ! But thinking its probably a short down to the chassis somewhere I thought all it would do is blow the fuse.... So I inserted a 10Amp fuse and turned on ignition - I heard a *CRACKLE POP!* come from the engine bay ! :( Followed by a slight whiff of that dreaded "burnt out" smell... Surprisingly the fuse didn't blow !! SO I powered down and restarted the car... The oil temp/level sensor alarm DIDNT come on and its now showing oil temp on the dash, the reversing lights and reverse sensors are working OK ! I haven't had chance to try the aircon because I have to put all the connectors to fan etc back in... And at least now I believe I should be looking in the engine bay for the fault. I will get VCDS plugged in and see what is now showing as faulty... Will investigate further and post results... Hopefully it might help someone else avoid having to fork out £100's to an auto electrician spending hours fault finding...

YUp - I will take a look at wiring going to the gearbox... Mine is indeed a MANUAL box - strange thing is that it still displays what gear I am currently in on the Maxidot display - so I'm guessing that part of sensing the gear selected is working OK - but am not sure if there is a separate switch on the gearbox for the REVERSE SELECTED position - I will have to try and find it... In my selection of fuses the only next size up is 10 amp - but I guess it wont hurt to try it because if its hard down to earth then it will simply pop that one too... Originally I focused all my attention on the HIGH PRESSURE switch of the air con - because the scenario when it first failed was that I was simply parked with engine running with air con ON for about 10 mins - then it just started to get warmer. So I switched off and restarted the car - when I restarted it it showed "OIL SENSOR - WORKSHOP" on the display with image of oil can - so I assumed (bearing in mind I wasn't actually travelling and it was fine for 10 mins) that I must have blown the high pressure switch on the air con - but I have since disconnected the switch AND the compressor BUT still got fault with it being down to ground... So may just be coincidental... I'll try a bigger fuse, and try and find reversing switch on gearbox... but its starting to look like ripping out loom and tracing cables ! :( And if I find it I will post here to try and help others because I've come across other threads describing same fault where the solution was never posted - and there was no response to several others asking "hey I have the same problem - what did you find..."

THanks again for the advice - and apologies... I think I was talking nonsense in my original post - having just checked for voltage on either side of the fuse carrier with the fuse out, I find that there is NO voltage (with respect to ground) on either end until I turn on the ignition - So my original comment saying it blows the fuse even with the ignition OFF was nonsense ! I was thinking that it blew a fuse as soon as I plugged one in - but it couldn't have done as there is no power to that fuse when ignition OFF. I've noted that the top of the fuse (incoming) is 480 ohm to ground when ignition OFF but changes to infinite (open circuit) with ignition ON. The bottom of the fuse (outgoing load) is showing 5 ohms to ground with ignition OFF and it jumps up to 10 ohms with ignition ON. By the way - where would I find the air quality sensor ?? - I'm not sure if I've managed to track that one down yet and disconnect it (and I've seen it mentioned in other posts). Thanks, Steve

ONce again thanks for all the feedback... Wino - the 12v supply is coming in at the top of the fuse (as expected) even with ignition OFF... There is a resistance of 480 ohm to ground on the top of the fuse carrier, the bottom of the fuse carrier shows only 5 ohms to ground with ignition off but surprisingly the resistance INCREASES to approx. 10 ohms when ignition turned ON !?! A666andy - I haven't tried upping the fuse rating - so I will have a go at that, HOWEVER, with only 5 ohms resistance down to ground on the fuse I suspect that it will simply blow a 7.5 amp fuse too - but certainly worth a try ! (I did consider shorting it out and see where the smoke comes from !! - but it would probably explode the battery and melt half my loom ! Having disconnected the High pressure sensor, the oil level sensor, the parking sensors and pretty much every connection I can reach under the dash I think I need to look at the reverse light switch but I am not sure if its located on the gearbox or the gearstick mechanism...? There is certainly some relationship with the reversing sensors and / or lights... Thank you. Steve

Hello and thank you for the repsonses. I think I shall indeed subscribe to Erwin - I looked at it but wasn't sure if I would be able to get the correct diagrams etc I need - but certainly useful and worth a shot. My engine code is CFFB Its a 2011 Skoda Superb Estate 2.0 Diesel. It has the automatic Climatronic control but does NOT have an auto dimming rear view mirror (which is something else apparently connected to Fuse no 4). Thanks, Steve

Hello ! Sorry to drag this back up after a couple of months... But did you resolve your issue with Fuse no 4 ? I have a 2011 Superb and it is blowing fuse no4 EVEN WHEN THE IGNITION IS OFF AND KEYS ARE OUT. I believe that fuse supplies the HIGH PRESSURE air con sensor in the front of engine bay near drivers side headlamp, its also the Oil Level / Temp sensor on the sump, its also for the reversing sensors (and probably reversing lights ?). I am REALLY struggling to find where mine is shorting out to ground... Running a fault check with VCDS reports those things mentioned above as not working (but then it would say that because as soon as the fuse blew all those things lose power !) I have unplugged my Air con gas sensor, the oil level / temp sensor and pretty much EVERY connector I can get my hands on behind the dash (I've removed the central vents / glovebox / side vents / radio etc) BUT I STILL HAVE ONLY 5 ohms to ground on that damn fuse ! I am thinking its a wire chaffing somewhere against the frame but I simply cant track it down ! AND BTW are there any good wiring schematics for the SKoda Superb MkII ?? I am struggling to find anything... Keep getting results for Octavia but am unsure if I can trust the schematic to be accurate (an incorrect wiring diagram can be worse than no wiring diagram !) Thanks for any advice ! Regards Steve