1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

MIL reading!

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by cabby, Jan 2, 2011.

  1. cabby
    Offline

    cabby 3.0 V6 sound

    Joined:
    Nov 25, 2010
    Messages:
    92
    Likes Received:
    3
    [Jan 2, 2011]
    hi chaps, i'm reading PO491 and PO492 on my 2.4, what's it mean and what do i need to do to rectify it.
    the car runs fine, if not a little under powered, but thats possibly because its a 2.4. ha ha.
    #1
  2. hades-
    Offline

    hades- Yorkshire & Humber Rep. Regional Rep VCDS Map User

    Joined:
    Jul 8, 2008
    Messages:
    9,256
    Likes Received:
    600
    [Jan 2, 2011]
    Secondary Air System
    prob the pump not running
    #2
  3. cabby
    Offline

    cabby 3.0 V6 sound

    Joined:
    Nov 25, 2010
    Messages:
    92
    Likes Received:
    3
    [Jan 2, 2011]
    thanks mate, any idea what i need to do, or is it a garage job?
    #3
  4. hades-
    Offline

    hades- Yorkshire & Humber Rep. Regional Rep VCDS Map User

    Joined:
    Jul 8, 2008
    Messages:
    9,256
    Likes Received:
    600
    [Jan 2, 2011]
    no idea never had this code b4
    someone else will pop up thats had this b4
    #4
  5. murran
    Offline

    murran Active Member

    Joined:
    Aug 10, 2010
    Messages:
    1,540
    Likes Received:
    37
    [Jan 2, 2011]
    sec. air injection pump faults bank1 and bank2.
    can you hear the pump running under the bonnet on cold start up?
    the sec.air pump system basically is designed to blow fresh air thru the egr system straight into the exhaust on cold start "choke" running. this is simply to bring down the hydrocarbon ppm readings at the tail pipe.

    with you having codes for both banks the other thing to check is the little pipes to the egr valves....
    they look similar to this.....
    EGR Combi Valve Passenger V6 Audi A4 VW Passat 96-05 - eBay (item 350394817426 end time Jan-14-11 14:26:23 PST)
    if you take the engine covers off and look on the back end of each head you'll see a similar looking unit bolted to the back of each head. these units are the egr valves. coming off them will be two smaller vac pipes.... are they split? check them back to the vac soleniod, the two pipes go to a t piece and then 1 pipe goes to the soleniod.

    do check these vac pipes before you take it to a garage. its a simple fix if its this!
    Last edited: Jan 2, 2011
    #5
  6. cabby
    Offline

    cabby 3.0 V6 sound

    Joined:
    Nov 25, 2010
    Messages:
    92
    Likes Received:
    3
    [Jan 2, 2011]
    thanks murran. her indoors as gone out in the car, so i'll give it a looking at later.
    i'm soon off for my sunday pint, might not get chance to look today!
    i did find info about it being both banks but nothing more, so thanks again.
    oh! do you think if the pipes are perished, it would make it drink more?
    #6

Share This Page