System Self-Test

System operation may be verified by entering self-test mode. Use scan tool to select self-test mode. See BODY CONTROL MODULES - CONCORDE, INTREPID, LHS & 300M article.
NOTE: Vehicle Theft Security System (VTSS) or VTSS self-test will be inoperative if Powertrain Control Module (PCM) has been replaced within last 20 ignition switch cycles.
Once in self-test mode, parking lights and taillights will flash and horn will sound twice. Parking lights and taillights flashing verifies their operation, and horn sounding twice verifies proper trunk cylinder position.
Turn ignition switch to OFF position to stop lights from flashing, while keeping system in self-test. While in self-test mode, a horn pulse should occur at each of following steps, indicating proper operation:
- Ensure all doors are closed. Open, then close each door. Horn will sound when door ajar switch closes and opens. There must be a one-second delay between closing and opening switch.
- Activate power door locks in both LOCK and UNLOCK directions. Horn will sound after each activation.
- Rotate key in both door lock cylinders to unlock position. Horn will sound when switch closes and opens. Ensure there is a one-second delay between changing switch states, or horn will not sound.
- Using RKE system, activate locks in both LOCK and UNLOCK directions. Horn will sound after each activation.
- Cycle ignition switch to RUN position. A single horn pulse indicates proper operation of ignition input and exits VTSS module out of self-test mode.
- For any of these tests, if switch does not remain open or closed for at least one second, the horn will only sound once.
Lack of horn pulse during any operation indicates a switch failure. Check for continuity at switch. If switch continuity is okay, check for open or shorted wire between switch and VTSS module.
Whenever a VTSS malfunction occurs, verify wiring harness is properly connected to all connectors before starting diagnosis and repair procedures.