Saxo VTR '03 Immobiliser issue

[dodyryda]

Hi..

Have a strange intermittent immobiliser issue with my VTR. Scenario is it wont start occasionally and I've noticed that when it does this the little orange immobiliser key symbol doesn't light on the dash when the key is initially switched on.. It then just turns over & over and will not fire..

A temporary workaround has been to disconnect battery terminal for 30 secs or so then replace. The key symbol light then appears and the car fires straight up. Turn it immediately off and it will restart repeatedly but if you leave the car walk away and return 5-10 minutes later and try to start the key symbol doesn't light and the car will not start.

The thing is it doesn't always do this. Last night left over night and it fired straight up this morning but stopped at garage earlier and problem appeared again.. I've removed the ignition transducer aerial to have a look and it looks fine.. I also replaced the crank sensor as this appeared as a fault code but this hasn't resolved it either.

Just owondeirng if anyone witha bit more experiance of these motors has come across similar issue or can suggest a resolution..

Thanks