General

PASS-Key(R) II is a registered trademark of the Delco Electronics Corporation.

When a key is inserted in the ignition, the contacts located in the ignition cylinder contact a resistor pellet located in the key. The Instrument Cluster (IPC) measures the resistance of the key pellet. The IPC then compares this value to a value stored in the IPC's memory. If the values match, the IPC sends a class 2 message to the Powertrain Control Module (PCM). The PCM then enables the starter system to operate. If the values do not match, the IPC does not send a starter system enable class 2 message to the PCM. The IPC does not enable the starter system for approximately 3 minutes. If the ignition switch is turned to the RUN position anytime during the system disable interval, the IPC disregards the key pellet value until the 3 minute system disable interval is complete (even if the correct key pellet value was used).

After approximately 3 minutes, the IPC measures the key pellet resistance. The IPC compares this value to the one stored in the IPC's memory. If the values match, the IPC performs the system enable function (see above). If the values do not match, the IPC performs the system disable functions again (see above).

If the IPC is unable to measure the key pellet resistance (due to a damaged or missing pellet), the IPC does not perform the system disable functions. Use a readable key with the correct resistance value in order to start the vehicle.