Hi Mike,
I seem to have much the same problem at present , 2007 Supercharged , likewise I replaced the battery under warranty , no change , can start car if I do the battery disconnect/reconnect procedure , however this will only allow one start up , when shut off the key cannot be turned again even if I leave the key in ignition.
I have noticed that the steering lock is not engaging , which I thought unfortunately was pointing towards the steering column solenoid being the issue.

Yep, looks like the steering lock ECU. I replaced fuse 18 with a switch and that's my temporary work around.

Next step is to replace the steering column since you cannot get the ECU on it's own. Apparently it's a common fault and my replacement is coming from California of all places and has a warranty.

I spoke to the seller in CA and his video's helped me confirm my worst fears.....that the column was stuffed.

The problem with using a switch to isolate the ignition circuit is that eventually the ecu will stop working altogether leaving you high and dry.

Mike

Last edited by mpirie on 31st Dec 2015 7:00am. Edited 1 time in total

Looks like I may have to do the same thing , have abandoned it at present in the driveway , will try to do some more research in the next few days and deal with it in the new year.

In the meantime, to avoid constantly disconnecting/reconnecting the battery, you can pull fuse 18 behind the glove box and reinsert it to perform the same function, or replace it with a fused switch.

Thanks for that Mike , will give it a try.
All the Best for the New Year.

When I get my new column installed, I may have the switch solution available for you if you want it

That would be great , Thanks.