Electrical & Lights Alarm Fault

Discussion in '2nd Generation (2002-2006)' started by tosher123, Thursday 9th Aug, 2018.

  1. tosher123 New Member Getting Started

    United Kingdom Thomas London
    My battery went flat after I left my light on, RAC jumped started it and since then when I lock my car after about 20 seconds the alarm goes of and won't stop until I start the engine, PS apart from this problem the car runs fine... Any answers?
  2. andy83 Club Veteran ★ ★ ★ ★ ★

    United Kingdom andy shropshire
    Hello mate please it would be nice if you introduce yourself here , have tried locking the car with key or fob, also have you tested battery voltage...
  3. cat-guy Club Member ★ ☆ ☆ ☆ ☆

    cat-guy United Kingdom
    Fix for Alarm Siren Sounding Continously
    This affects all when the battery (The battery in the engine bay not your key fob) isn't holding a good charge. When the vehicle is unlocked with the key fob the siren sounds continuously and cannot be stopped.

    This is normal when the battery has low voltage or is dead, when you unlock the car with your fob , it sends the signal to the MICU(Multiplex Integrated Control System ) to unarm the car,but when it senses low voltage from the battery it goes into a loop.Due to this low battery voltage the MICU is unable to communicate with the Alarm Control Siren(ACS) to signal it to disarm it.

    Because the MICU and ACS now have different armed/unarmed status the siren will sound using its backup battery and will continue so long as the MICU and ACS remain in different armed status.

    The Fix

    You need to charge that battery up to full charge. Then lock the vehicle with the key fob.Wait, approximately 15 seconds, for communication to be established between the MICU and ACS. The indicators will flash rapidly to indicate when you see this both MICU and ACS are in sync