Could be the key or the sensor in the ignition switch. Try this and see if it helps
GM PASS LOCK RELEARN- Ignition to "run" position, try to start and let key return to "run" position
Approx ten minutes security light will go off
Turn key "off" and wait 5 seconds
Repeat 2 more times for a total of 3 relearns.
Turn key off, then start it
Saturday, August 16th, 2008 AT 8:08 AM