i got the em light up the other day . on my mk3 gsi phase 2 (x20xev)
paper clip test came back with code 0500 with i believe means Idle speed stepper motor/idle air regulator
so i replaced this (only use for picture)
http://cgi.ebay.co.uk/Vauxhall-Idle-Air-Control-Astra-Vectra-Omega-B-Calibra_W0QQitemZ120327610871QQcmdZViewItem?hash=i tem120327610871&_trksid=p3286.c0.m14&_trkparms=72% 3A1301|66%3A2|65%3A12|39%3A1|240%3A1318
but i still have the light on, i have left the battery off over night still on next day
retested and got same code
anyone got any ideas what to do next ???