ASC Light On

  • Hi all,
    I have a 1997 840ci, a few weeks ago my ASC light came and then the check engine light (the 1997 840ci's did not have a check engine light on, however I asked Gerry Speechley to put a bulb in in several years ago). I also noticed that at idle the car felt it was not getting enough throttle and on one occasion the engine went off. I have taken it to a local mechanic and the found 2 fault codes both to do with the front wheel speeds not being plausible. They reset the codes, and the car drove fine for about 20 miles and now the lights are back on and again the car feels it is not getting enough throttle and threatening to switch itself off as well as misfiring.
    Any thoughts on what this could be?

  • Two potentiometers on air intake manifold, one for ASC throttle body. Check these. They are identical and in close vicinity to each other. Judging from parts catalogue the one on top is for ASC.


    8er.org/forum/index.php?attachment/45036/


    Misfire/cutting out sounds more like camshaft sensor or possibly crank sensor. Failing camshaft sensor often gives errors until memory overflow (255) but has also been seen failing without any error codes in memory.


    8er.org/forum/index.php?attachment/45037/


    Cheers
    Reinhard

  • Thanks Jonannes - I don't usually use the AC but will try this.
    Thanks Reinhard, the garage owner has an e31 and his mechanic did mention something about an airflow sensor being responsible, work is in the way at the moment, but I will provide an update as soon as some progress is made.

  • Backfiring usually means the CAMshaft sensor is failing - more info here:


    https://www.meeknet.co.uk/e31/…ft_Sensor_Replacement.htm


    ASC warning on its own usually points to a kinked ASC Bowden cable between the actuator and secondary throttle


    [video=youtube_share;W_bbKxFBKqA]

    Externer Inhalt youtu.be
    Inhalte von externen Seiten werden ohne Ihre Zustimmung nicht automatisch geladen und angezeigt.
    Durch die Aktivierung der externen Inhalte erklären Sie sich damit einverstanden, dass personenbezogene Daten an Drittplattformen übermittelt werden. Mehr Informationen dazu haben wir in unserer Datenschutzerklärung zur Verfügung gestellt.
    [/media]

  • Thanks Timm, the backfiring only started after the ASC-T light came on, started the car today and the ASC light was off, left stationary, after a few minutes the light came on and the car felt as if it is loosing throttle but did not switch off. Still trying to find time to get it to the garage.

  • Hi, just a quick update and some more advice required please: the air mass sensor is definitely faulty, BMW have quoted close to £500.00 and a 2-3 week wait from Germany. There was also a fault with the ABS pump, this was sent to a specialist repairer but they have said they cannot read any codes on the pump, the pump is coming back to be fitted tomorrow. I am hoping the ASC-T light came on because there was an issue with the air mass sensor rather than a problem with the pump. Would appreciate advice on where I can get an air mass sensor from but as a better price than BMW? Also the garage mentioned my spark plugs could do with a change and I wonder if this could be contributing to some of the problems? Advice appreciated.

  • If, when talking about the ASC+T pump unit (the bit with all the brake pipes going to it), the specialist repairer failed to find any fault codes - that's hardly surprising as there are no electronics in it - just the motor and ten solenoids. The ASC+T module is in the left-hand footwell. The modules rarely go wrong, but if the ASC light is coming on then fortunately the ASC+T system can be read by INPA with a moderns USB (one of the few things it does read)!

  • Zitat von Timm;151894

    ...
    the specialist repairer failed to find any fault codes - that's hardly surprising as there are no electronics in it - just the motor and ten solenoids.
    ...


    Just having the same thoughts!!! :rofl:
    Great specialist... :roll:

    .


    Das was du heute denkst, wirst du morgen sein.
    Buddha


    .

  • Hi Johannes, I have seen the Bremi ones and some Mapco ones for a fraction of the price, what issues did Stefan have as the links will not work for me?

  • [FONT=&amp]Hi there,[/FONT]
    [FONT=&amp]Just an update, new MAF sensor arrived, fitted and so far so good, have done approximately 100 miles, no bings, no bongs and no lights on my dash. Waited 2 weeks to arrive, link to MAF sensor below, I did email them prior to getting it and they confirmed it should work. Car sounds great and feels great, fingers crossed it stays this way. Thanks Timm et al.
    [/FONT]
    [FONT=&amp]
    https://www.ebay.co.uk/itm/352993407961[/FONT]

    [FONT=&amp]
    GENUINE SKV HEAVY DUTY AIR MASS SENSOR FOR BMW 540i 740i 840i E34 E32 E38 E31[/FONT]

Jetzt mitmachen!

Sie haben noch kein Benutzerkonto auf unserer Seite? Registrieren Sie sich kostenlos und nehmen Sie an unserer Community teil!