If your car has an immobiliser (if you are WA chances are high) this may be helpful. If you drive only newish cars don't bother reading on:-)
The engine of my car stopped last night and couldn't be re-started: no ignition voltage, in fact no lights on the instrument panel at all. I suspected the immobiliser (it was immobilised alright!)and opened it up.
After locating the black box under the dash, pulling it out and removing some very sticky tape and a cable tie, I saw that it was built in 2003. It has the type code 6XR V4 and seems to be this model:
After re-soldering it works just fine again.
This could have been an intermittent fault and stuffed me around a lot! I was kind of lucky.
(If it happens to you and you DIY, make sure you disconnect power first or you might cause more damage)
Tony