Hi, i have a 1998 p38 2.5 TD And having problems with engine immobilised, ive tried the usual EKA new fob batteries etc , i can`t open car on fob so assume the alarm remains armed, the question is should the back up battery fail in the Klaxon will this cause system to remain armed and have an Issy fit? if so can replacing unit cure it or is it coded to the BECM ? Cheers Dave