Car

The most common failure in these is the sensor in the ignition lock that reads the key pellet. That would mean replacing the ignition lock with a sensor included.

That sensor can be bypassed. You would need a digital ohmeter to measure the resistence of the pellet in the key. Now go to Radio Shack and buy a resister of the exact same value as the key pellet. Go to the base of the steering column and locate the two thin white wires that go up to the sensor. Cut the two wires and solder the resister between the two ends coming from the harness. This will permanently bypass the sensor but not the rest of the system so if the problem is elsewhere, this won't help. Make sure your measuring the original key.