Passive anti-theft system

Pos.	Spare Part No	Name
1	-	Powertrain control module (including PATS)
2	-	Passive anti-theft system transmitter
3	-	Anti-theft warning lamp

Passive anti-theft system (PATS)

Passive anti-theft system (PATS) is completely passive in nature and does not require the driver to perform any special procedures to turn it on or off. During normal inspection, the system is invisible, it is controlled by a miniature repeater built into the key body. This repeater communicates with the module via a transmitter mounted around the perimeter of the ignition switch lock cylinder.

The PATS functionality is built into the powertrain control module.

The presence of a PATS system can be identified by a larger ignition key, which indicates the presence of a repeater controlling the system.

The PATS repeater key is uniquely designed for the Ford Focus; it can be identified by the blue inset. Previously used keys with PATS repeaters with red inserts are not compatible with Ford Focus vehicles and must not be used.

The repeater code is read when the key inserted in the ignition lock cylinder is turned from position 0 to position III to crank the engine. If the PCM recognizes the required code, the engine starts. If the PCM does not recognize the code or receives the wrong code, the engine will not crank because the PATS is still enabled and the engine is still immobilized.

Anti-theft warning lamp

Each time the ignition is turned on, the theft deterrent warning light stays on for three seconds to indicate that the system is performing the initial ignition key code reading. The anti-theft warning light flashes rapidly or stays on after the first three seconds, indicating that the PATS system has immobilized the vehicle.

For more information about PATS trouble codes, see "Diagnostics and testing".

General information

Passive anti-theft system (PATS) uses RFID technology to prevent theft. This system is known in North America as SecuriLock and in Europe as PATS. "Passive" means that the system does not require any action on the part of the user. This PATS system provides the following:

• No master key required.
• The VIN data is stored in the module.
• There are special functions for fleet customers.
• It is possible to encode a spare key and erase the code.
• Circuit for transmitting encrypted CAN data in DI diesel engines (PCM - PCU).

Coded ignition key

The PATS system uses a special coded ignition key. Each coded ignition key is equipped with a permanent electronic repeater device. Each repeater has a unique electronic identification code selected from millions of combinations. Each coded ignition key must be programmed for the vehicle's PATS control function, which is part of the powertrain control module (PCM) before the key can be used to start the car engine. This manual describes specific diagnostic repair procedures that should be followed if a coded ignition key needs to be replaced. PATS keys designed for Focus vehicles have blue transponders built into the key head. Only Ford approved ignition keys should be used, as some commercially available ignition keys purchased from non-Ford approved dealers may malfunction, especially at high and low temperatures. In order to be able to start the engine, at least 2 coded ignition keys must be programmed for the vehicle. A maximum of 8 ignition keys can be programmed for a car. The PATS control function in the PCM enters Anti-Scan Mode if an unprogrammed ignition key is used to start the engine (correct form).

NOTE: If an unprogrammed key was used, the code reading of any subsequent key is blocked for 20 seconds. During these 20 seconds, the car engine cannot be started with any ignition key. To exit anti-scan mode, turn the ignition key to the ON position and wait 30 seconds, turn the ignition key to the OFF position and remove the key from the lock. Then turn the ignition switch to the ON position with the correctly coded key.

PATS control function

The PATS control function is provided in the PCM. This module performs all PATS functions such as receiving and identifying a coded ignition key code and controlling engine and starter activation. The PATS control function initiates a key request sequence when the ignition switch is turned to the RUN or START position.

Transmitter module

The transmitter module communicates with the coded ignition key. This module is located on the molded part of the ignition key cylinder and has an antenna connected to a small electronic module. Each time the vehicle's start sequence is started, the transmitter module reads the coded ignition key ID and sends the data to the PATS control function located in the PCM. When removing or installing a new PATS transmitter, no re-initialization is required.

PATS objective function

In vehicles equipped with 1.8 DI diesel engines, the high pressure fuel pump has a pump control unit (PCU) (PATS objective function). The PATS control function in the PCM communicates with the PCU to activate or disable the engine. The PCU must receive the required wake-up sequence from the PCM via the CAN network within 1 second or less after the engine is started or before the engine is turned off. The PATS control function and the PCU exchange security codes when they are wired together, after which they form a matched pair. These exchanged security codes are stored in memory even if the vehicle's battery is disconnected. Therefore, after the exchange of the specified security codes, these modules will not function in other vehicles. If the PCM or PCU is being replaced, specific diagnostic procedures must be performed using the FDS 2000. All elements of the PATS system must be operational before the engine is allowed to start. If any of the components are malfunctioning, the vehicle's engine will not start and the anti-theft warning lamp will flash a fault code.

Anti-theft warning lamp

The PATS system uses a visual warning light for the anti-theft system. This warning lamp performs a self test for three seconds when the ignition switch is turned to the RUN or START position in normal operating mode. If the PATS system malfunctions, when the ignition switch is turned to the RUN or START position, the warning lamp flashes quickly or stays on, and then displays a visual fault code 10 times. Refer to Diagnostic Trouble Code List (DTC) in this section, or connect to the FDS 2000 and follow the on-screen instructions. The PATS system also turns on the anti-theft warning light every two seconds when the ignition is off (OFF position) for visual confirmation of system operation.

J1850 communication network

J1850 communication network (SCP) used for diagnostic purposes only. The CAN bus is used to send and receive messages exchanged between the PATS control function and the PCU.

Starter relay

The starter relay is also used as an additional means of blocking the car's engine. The relay is latched if the PATS system cannot read the encoded ignition key code when the ignition switch is in the ON position. However, the system does not store a DTC or generate a flashing code with the theft alarm warning lamp if a correctly coded ignition key code is read and the starter relay circuit is malfunctioning. See Section 303-06 for more information. The relay is unlocked when the PATS control function reads the code of a correctly coded ignition key in the ignition ON position. The PATS system will activate and prevent the vehicle from starting if the following is detected:

• Damaged coded ignition key
• Unprogrammed key
• Unencrypted key (the key has no electronic elements or a blue repeater)
• Damaged wiring
• Damaged transmitter
• Damaged PCM
• Ignition key shield