Troubleshooting (Security & Locks)

Principles of Operation
The passive anti-theft system (PATS) uses radio frequency identification technology to deter a drive away theft. Passive means that it does not require any activity from the user. This system is known as SecuriLock in North America, Safeguard in the U.K., and PATS in continental Europe.

The PATS uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code out of over four quadrillion possible combinations.

Each encoded ignition key must be programmed into the vehicle's powertrain control module (PCM) before it can be used to start the engine. There are special diagnostic repair procedures described in this section that must be carried out if a new encoded ignition key is necessary.

The PATS transceiver communicates with the encoded ignition key. The PATS transceiver is located behind the steering wheel column shroud and contains an antenna connected to a small electronics module. During each vehicle start sequence, the transceiver reads the encoded ignition key identification code and sends data to the PCM.

The control functions are contained in the PCM. This module carries out all of the PATS functions, such as receiving the identification code from the encoded ignition key and controlling the engine enable. The PCM initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.

All elements of the PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle will not start.

The PATS uses a visual theft indicator. The indicator will prove out for three seconds when the ignition switch is turned to RUN or START under normal operation. If there is a PATS problem, this indicator will either flash rapidly or glow steadily when the ignition switch is turned to RUN or START The PATS system also flashes the theft indicator every two seconds at ignition OFF to act as a visual deterrent. The PATS theft indicator is located in the hybrid electronic instrument cluster (HEC). The anti-theft indicator illumination is controlled through the standard corporate protocol (SCP) communications network. The PCM sends the illumination command through the SCP communication network to the HEC. The HEC then triggers the anti-theft indicator to illuminate. For more anti-theft indicator information see INSTRUMENT CLUSTER. The PATS will be activated and will disable the vehicle from starting if there is:
- an incorrectly encoded ignition key.
- a damaged encoded ignition key.
- an unprogrammed key.
- a non-encoded key (key has no electronics).
- damaged wiring.
- damaged PATS transceiver.
- damaged PCM.
- a module communications network concern.

Anit-Scan Feature
This feature will not allow the vehicle to start or crank it a non-programmed key is tried. The security light will flash rapidly as long as the un-programmed key is left in the ON position (during anti-scan mode) until 60 - 65 seconds has passed, it will briefly turn OFF, then the security light will begin flashing out a trouble code (15). One of the following two steps must be followed to cancel the anti-scan mode. Otherwise, the vehicle will remain in the anti-scan mode indefinitely.

1. Remove the un-programmed key after you enter the anti-scan mode (before 60 - 65 seconds have elapsed), and then insert a programmed key into the ignition. Turn it to the ON position, wait 60 - 65 seconds (until security light quits flashing) and then you can then turn the key OFF, then back ON and start the vehicle normally. Now the all previously programmed keys will again work normally.
2. With the un-programmed key in the ignition and in the ON position and the security light flashing rapidly, wait 20 seconds, turn the un-programmed key OFF and remove it. Now insert a programmed key in the ignition, turn it to ON, and start the vehicle. Now all previously programmed keys will start the vehicle.