If you can find someone with a scantool that can access the BCM (most likely to be holden) ,they can test the BCM functions and they can tell you if theres anything up with the BCM.The BCM stores error codes for different problems but these codes can only be accessed and read with a scantool.The BCM is located up under the dash just behind the fuses under the steering column.It is not hard to get out,a couple of screws or clips,I cant quite remember which,then unplug the wiring,thats it,swap them over then.You will need a matching key fob.(for the immobiliser).The key security code has to match the BCM security code to disable the immobiliser,so the engine can start.You might be able to get a new BCM programmed with your existing key code.Im not 100% sure about this though,but Holden would have to do this.They can access the security info for your car from your VIN code.