Hi All i have encountered a weird problem with my skoda octavia 1.6 Classic 55kw it doesnt idle properly everytime i turn on the air conditioner the idling rpm drops from 750 to 350 rpm and then on occasion stalls. The aa guy said its the fast idling device that has malfunctioned and so we went to the local independent garage to get it fixed they said it was the throttle body and charged us $180 to get "clean it" after reciving the car the problem only got worse now when idling the car starts to rev all by itself from 1500rpm to 2300 rpm over and over again i was wondering what is wrong? and is there anyone u can recommend in singapore to have it fixed?

Mine did much the same, and it was the crank position sensor...not sure if this will be of help to you...

Rob.

Hey thanks rob but i was wondering do u need to replace the entire throttle body? cause they said that i would cost over 1000 sing dollars to do so? is it possible to change just the crank position sensor?

Yes, the crank position sensor can be changed on it's own - was about

Thanks for the info and one more thing is there like a vag com error when there is something wrong with the crank position sensor?

Mine had an error logged for it, but then mine had failed to the extent of the ECP (or is it EPC?) light coming on, and the car not starting, then starting, revving about a bit, then stalling no matter what I did with the throttle.

Rob.

hmm okay but the thing is that its an 55kw engine and it doesnt have a check engine light or an EPC light so i am not very sure and i dont quite trust the garage who is servicing the car but ihave no choice as i dont know who else to go to thanks though

Hi just went to the garage again they said that the computer has to "learn" the driving style of the driver since they deleted the information when the throttle box was cleaned and that after a week the problem will go away? is that true?

Hi just went to the garage again they said that the computer has to "learn" the driving style of the driver since they deleted the information when the throttle box was cleaned and that after a week the problem will go away? is that true?

Doubtfull.

Has the throttle valve been reset electronically with VAG COM?

Thanks for the reply.I have no idea whatsoever and i dont even know if they have cleared it especially since we called 2 garages and they both said the same thing and that it would "learn" and the problem would go away we dont trust the dealer and we have no experience with the garages. Anyway the problem seems to go away when the A/C is off and when it is on the engine idles roughly and that it would rev from 1600rpm-2000rpm and sometimes the car even moves off on its own. i dont know it all started when the car started dying everytime the A/C went on and the rpm fell to 500rpm and now after they have cleaned it up this happens. Does anyone know what the possible problem is?

Hmm...well, considering that I'm not a mechanic and don't really know what I'm talking about, but someone more knowledable will correct me if I'm talking complete nonsense...

If it's just happening when the air conditioning is on, could it be anything to do with the compressor belt? Just thinking, if the mechanism which drives the A/C compressor from the engine is being too resistive (worn bearings, etc?), the idle sensor may increase the revs to prevent the car from stalling.

Have you tried looking under the bonnet while the engine is running, both with and without the A/C on, to see if anything looks odd?

Rob.

Hey rob i have actually tried looking but apparently nothing seems amiss thanks though anyway i plan to wait for a while and see if it goes away first hope it does

i have had cars in the past which had this problem! it's bloody annoying!!!

i had the throttle position sensor cleaned and reset (idle position sensor)

also another of my cars had the same sort of thing and that was the inlet manifold pressure sensor.

Sounds like a setting fault with the throttle body to me.

Idle is increased when the air con compressor is switched on to compensate for the additional load put on the engine and thus stopping it stalling, the same happens when the PAS is on full lock.

Could be a faulty PAS sensor (sits in the top of the solid metal pipe on the pump itself, try pulling the plug off and see what happens)

that was my next choice!!

There are standard DTCs (Diagnostic Trouble Codes) specific to the crankshaft position sensor, ie 16719, 16720, 16721, 16724, 16725, 16726 and 16727. Also 17747 and 17748. You can find a complete list on Bentley Publishers site here:

http://www.bentleypublishers.com/tech/vw/vw.dtc.table.htm

Please note that this list may have been edited by Bentley Publishers to make it VW-specific.

Hmm okay but i am not too sure where it is thanks anyway ross and nlj but why do u suspect that it is the the PAS and not the AC? i called the mehanic again and they said it could be the breather tube. is there a way to reset the throttle body sensor? Thanks once again

hey thanks for the codes Denis really appreciate it

is there a way to reset the throttle body sensor? Thanks once again

As Ross said, the throttle body can be recalibrated using VAG-COM software. I have just bought an interface lead and software from Ross-Tech in the USA. Have a look at their site here for further information:

http://www.ross-tech.com/

Hey thanks but apparently most pple in spore say that it will go away for awhile so i guess i will wait and see at most i would have to change the entire throttle box then thanks once again