Hi all,

New to forum but I have run into an issue trying to do good deed for bonus daughter. She has a Fabia Mk1 2004 and was having some issues with idling fuel usage. I thought an easy check would be cleaning the throttle body. It seemed easiest to remove it for cleaning which I did and from what I originally found online as long as gentle you could open the valve manually for cleaning, in true my normal operating form after that when I had problems I found all the info not to manually open as it causes problems. When I had it cleaned up and put it back on immediately the EPC light came on and it went into limp mode and won't come out. I have tried various ways to reset it (battery disconnect, key on for 30 seconds, etc) but nothing is making a difference. After a battery disconnect it goes into that EPC mode immediately. When the key is first turned on the valve flutters then does nothing. Now an interesting thing is even before I cleaned it, turning the key on and pressing the accelerator pedal did nothing as far as opening the valve whereas I see information it should open? Anyway, I am trying to figure out best option now as the car is inoperable and she returns tomorrow. :-( I have tried checking the pins on the throttle body with a multimeter but not sure I am following right pattern but the results there did not seem to give promising feedback. I also am not finding any of these available except for one about 1.5 hours away which might be my next step if nobody has anything to try.

Thank you in advance for any help.

DDW

Think it may need re calibrating using vcds etc but did read on another forum you could try turning on ignition but dont start car or touch any pedals. Leave for 3mins exactly. Turn off and wait for 10-15secs and start car. Leave idling for a few mins.

If the above doesnt work try disconnecting battery for 30mins and reconnect. Turn on ignition without starting car for 1 min then start car and leave to idle for 10 mins.

Hope it helps

Alasdair

Hi and thanks for reply! I have tried several different reset options around battery disconnect and then key on for 30 seconds and off for 30 seconds (also longer periods and also letting it idle) but it seems pretty stuck in the EPC limp mode. Interestingly one time when I was trying reset it seemed to be working and revving normally etc but immediately when I took foot off brake it freaked out and went back into limp mode which seemed very weird and should be unrelated. I have verified ok hoses connected and nothing else was disturbed in process.

I am wondering if I messed up the insides opening it manually to clean (pushing valve open)

How is the VCDS set? I assume that needs to be at a shop?

Thanks,

DDW

VCDS is vw group diagnostic software which you can buy from Rosstech. Someone on here may have it near you and could help recalibrate it for you. If not it will need to be done at a vw/skoda garage or specialist unless your local garage has access to vcds or alternatively OBDeleven. On another thought are your brake lights working. A failed brake light switch can cause EML and limp mode?

Alasdair

Hi, I will check the brake lights but would be big coincidence if that failed while I was cleaning throttle body :-) though murphys law does love coincidences. I have ordered a cable as it looks like for a 2004 the VCDS lite might work to reset it or at least read the codes and see what is going on. Just don't know if I should order a new throttle body just in case or not. Will have to be an order as nobody carries them locally.

Thanks,

DDW

Even if the brakes lights work it could be coincidence and the switch is failing. Something about the car thinking brakes and accelerator are being pressed at same time so cuts power. Think you can do the calibration with vcdslite and also it may ping up some other fault codes that generic readers miss.

Alasdair

1 hour ago, DDW said:

Hi, I will check the brake lights but would be big coincidence if that failed while I was cleaning throttle body :-) though murphys law does love coincidences. I have ordered a cable as it looks like for a 2004 the VCDS lite might work to reset it or at least read the codes and see what is going on. Just don't know if I should order a new throttle body just in case or not. Will have to be an order as nobody carries them locally.

Thanks,

DDW

Buy a secondhand one as they rarely fail.

Match the entire part number including letter suffix.

A second hand one will put me back in same circumstance of needing to clean it 😃 do you think the one I did clean is okay and the limp mode EPC code is just not going to clear without the vcds clear? Looks like a controversial subject on here if they will clear by itself or not. I did unplug it when cleaning. Guess will know for sure when the cable comes later

You just clean what you can without moving the butterfly, which is 98% of it. They don't sit fully closed when unpowered if I remember right.

So far I don't know which engine type you have, so it's hard to know specifics.

Have you checked the brake servo vacuum hose for splits or cracks at the junctions of the hard plastic sections?

Hi again,

Okay, I left it on charger for the day and then disconnected battery and put the throttle body back in place. I then connected battery and did the 3 min with key on and it went through a bit more movement than it was last night. I then turned key back off and back on then started it. EPC light still on but limp mode gone. Drove it around a bit and EPC light stayed on. Got back to house shut it off and started it again and EPC light went off… no idea but seems to be fine. I still have the cord coming so will try and see if it gives any info when it comes but maybe a slightly low battery was causing issues? No idea what else it could have been.

Thanks for the responses, always good to have someone responding when fighting through these things.

Thanks,

DDW

what I read was exactly three mins so maybe critical and a low battery can cause all manner of spurious faults. Glad its back to normal for now and hope it stays that way. Worth scanning it anyway to see if theres any underlying problem.

Alasdair

1 hour ago, DDW said:

Hi again,

Okay, I left it on charger for the day and then disconnected battery and put the throttle body back in place. I then connected battery and did the 3 min with key on and it went through a bit more movement than it was last night. I then turned key back off and back on then started it. EPC light still on but limp mode gone. Drove it around a bit and EPC light stayed on. Got back to house shut it off and started it again and EPC light went off… no idea but seems to be fine. I still have the cord coming so will try and see if it gives any info when it comes but maybe a slightly low battery was causing issues? No idea what else it could have been.

Thanks for the responses, always good to have someone responding when fighting through these things.

Thanks,

DDW

I used to clean a 2005 Polo throttle body but I did it in situ, remove air cleaner, switch on ignition and put a "brick" on the accelerator, this will/should open the throttle valve fully to allow gentle cleaning of most of the throttle body, the revs used be on the high side after the clean for a few miles of driving but used to settle back down to normal. I have VCDS but never used it after cleaning.

Your 2004 Fabia may have still had a cable operated throttle valve but the idling is/was still done electronically, the motor on these used to fail occasionally, I replaced them on a few friends 2000 Boras with used ones, again (and I didn't have VCDS then), idling speed would normalize after a few miles.

Also, as suggested above......"check the brake servo vacuum hose for splits or cracks at the junctions of the hard plastic sections"

Edited 1 hour ago1 hr by Johngerard