Pass Key Diagnosis
WARNING: This page is about a different car, the 1990 Cadillac Seville and 1990 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
The pass key system interfaces the ECM and starter with a power source, decoder module, starter enable relay, ignition switch and instrument cluster. Before replacing pass key module, check the system for the following common problems.
- Check ignition key pellet sensing contacts in the ignition lock cylinder. Look into cylinder lock. If contacts are damaged, replace cylinder lock.
- Check pass key, ECM and GAUGES fuses
- Check security indicator bulb in the instrument panel.
- A defective resistor pellet within the ignition key or incorrect resistance value of key (15 different assigned values) will cause vehicle not to start. Key must be correct electrically and mechanically.
If incorrect key is used to try to start vehicle, decoder will not allow vehicle to start for 2-4 minutes, even if correct key is inserted.