GM Service Manual Online
For 1990-2009 cars only
Lockout Timer:  The duration of time the system remains in tamper mode The VTD system will disable sampling of the key code for 3 minutes when a tamper is detected.

Auto Learn Timer: The duration of time the system remains in the re-learn wait mode.

Seed and Key Timer: The scan tool displays the time in seconds used by the BCM to learn a valid code from the passlock sensor. The learn procedure consists of 3 seperate periods.

Passkey Data Voltage: Displays the voltage data from the Passkey Sensor to the BCM. The BCM determines if the data received is valid or invalid.

Security Lamp State: Indicates the state of the SECURITY indicator either On or Off.

His DTC Cyc. Counts.: Displays the number of key cycles that have occured in order to clear history DTCs.