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Diagnostics/ VCDS

Discussion in 'A3/S3 Forum (8L Chassis)' started by Rob45, Oct 6, 2013.

  1. Rob45
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    Rob45 Member

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    [Oct 6, 2013]
    Morning everyone , just looking to pick some Brains on another issue !

    Recently noticed the S3 is a little bit lumpy on tick over , only ever so slightly , that miss a heart beat feeling !!!

    In the near six months of owning this now , i have changed things like split breather pipes etc and familiar with that as had a TT before so know these suffer with this sort of stuff and there was a few codes coming up ref to boost leak issues so as said , i have corrected what i found to be at fault .

    Just had had car on VCDS again this week because of this idle drop issue , well everything seem to be fine apart from one fault that come up which was

    16486-Mass Air Flow Sensor (G70) P0102 -35-10- Signal too low - intermittent

    I did have my suspicions it could be MAF related , i have now removed sensor from housing and give a good spray with contact cleaner and left to dry , running idle deffo seems better and holding where it should .

    My question is , could there also be prob with coolent temp switch ? or would this have shown up on VCDS ? as i know somethimes these are at fault even though temp in car is sat at 90 degs , it does have an updated green one..

    Only reson i ask this is fuel consumption is not great , i know a faulty maf would cause poor fuel return figs and also coolent sensor as ECU is thinking car is still not up to temp so will be running at cold engine settings or is it my heavy foot ?

    Temp gets to 90 pretty quick and stays there so stat seems to fine .. thinking maybe worth while getting a new maf and change the coolent sensor as not the earth in £££ and will not do any harm..


    Is there anything else to check but as siad VCDS did not have anything else flag up , oh apart from central locking which was 01367 central locking pump run time exceeded (likely leak) but seems to lock ok so not even going to get involved with this unless it stops all together.
    cheers
    Rob
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  3. slowcoach3
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    slowcoach3 Active Member

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    [Oct 6, 2013]
    Looks like an old maf that needs changing or a broken maf plug itself. Try unplugging the maf and going for a drive, if it drives better with it unplugged then it needs changing. You could also do a wot run in 3rd gear while logging block 002 in vcds, if your g/s readings are very low then that would also point towards a tired maf IF the rest of the car is all working correctly.
    If the temp sender is green and genuine then that should probably be ok, if its black or a copy then it may not be working 100% but if your temp gauge reads 90 your more than likely ok on that front. You can also read the water temp on the air con lcd screen using channel 49...
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  4. Rob45
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    Rob45 Member

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    [Oct 6, 2013]
    Cheers, was going toask how to do this check on the A/c please , so how do i get to do this ? So temp should be same as pod guage yes ? 90 Degs ?

    I think i will also get a new MAF , is the Eurocarparts/ carparts4less one ok ?
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  5. slowcoach3
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    slowcoach3 Active Member

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    [Oct 6, 2013]
    Its always preferable to buy mafs from tps/audi as they are pretty much guaranteed to be calibrated correctly but as long as its genuine Bosch you should be ok. Iirc hold the up arrow and press econ button on the a/c panel and it should come up with 1c, keep pressing up as if you were changing the temp till you get to 49c and hit the econ button again and you'll get a live reading. I may have fecked that description up so have a little search to double check.....
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  6. Rob45
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    Rob45 Member

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    [Oct 6, 2013]
    Ok cheers , will have a look , any others to check while i'm at it ? but as said VCDS did not show any other faults apart from mAF , As said , i have cleaned with electrical contact cleaner and realy cannot see any drop now on rev counter needle but the issue with fueling , could still be the MAF giving wrong signal and cause over fuelling yes ? , exhaust tips are quite black , dont really want to unplug MAF and drive as i have heard can damage other O2 sensors (lambda ) if gets too hot ???
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