GM Service Manual Online
For 1990-2009 cars only

Condition

Action

The lock cylinder is faulty.

Replace the lock cylinder. Refer to Ignition Lock Cylinder Replacement - On Vehicle .

The ignition switch is faulty.

Replace the ignition switch. Refer to Ignition and Key Alarm Switch Assembly - Disassemble - Off Vehicle or Ignition and Key Alarm Switch Assembly - Assemble - Off Vehicle

The lock module gear train is jammed.

Replace the lock module. Refer to Electronic Column Lock Module - Disassemble - Off Vehicle or Electronic Column Lock Module - Assemble - Off Vehicle .