Passive anti-theft system (Focus 1)

Contents: Passive Anti-Theft System (PATS) ↳ Anti-theft alarm system indicator… ↳ General information ↳ Coded ignition key ↳ PATS control function ↳ Transmitter module ↳ PATS objective function ↳ Anti-theft alarm system indicator… ↳ J1850 Communication Network ↳ Starter relay ↳

Pos.	Spare Part No	Name
1	-	Powertrain Control Module (incl. PATS)
2	-	Passive Anti-Theft System Transmitter
3	-	Anti-theft alarm system indicator light

Passive Anti-Theft System (PATS)

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

PATS functions are integrated into the powertrain control module.

The presence of the PATS system can be identified by a larger ignition key, indicating the presence of a repeater that controls the system.

The PATS key with repeater has a unique design developed for Ford Focus vehicles; it can be identified by the blue insert. Previously used keys with PATS repeaters, which have red inserts, are not compatible with Ford Focus vehicles and should not be used.

The transponder code is read when the key inserted into 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 an incorrect code, the engine does not crank because the PATS system is still enabled and the engine immobilization remains.

Anti-theft alarm system indicator light

Each time the ignition is turned on, the anti-theft system indicator lamp remains illuminated for three seconds, indicating that the system is performing an initial reading of the ignition key code. The anti-theft alarm indicator light will flash rapidly or remain on continuously after the first three seconds, indicating that the PATS system has immobilized the vehicle.

For more information on PATS fault codes, refer to the Diagnostics and Testing section.

General information

A Passive Anti-Theft System (PATS) uses radio frequency identification technology to prevent theft. This system is known as SecuriLock in North America and PATS in Europe. "Passive" means that no user action is required to operate the system. This PATS system includes:

No master key required.
VIN data is stored in the module.
Special features are provided for fleet customers.
It is possible to encode the 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 has a permanent electronic device called a transponder. Each transponder has a unique electronic identification code selected from millions of combinations. Each coded ignition key must be programmed to the vehicle's PATS control function within the powertrain control module (PCM) before the key can be used to start the vehicle. This manual provides specific diagnostic repair procedures that must be performed if a coded ignition key needs to be replaced. PATS keys designed for Focus vehicles have blue transponders embedded in the key head. Only Ford approved ignition keys should be used as some commercially available ignition keys not purchased from Ford approved outlets may not function properly, particularly in hot or cold temperatures. A minimum of 2 coded ignition keys must be programmed to the vehicle to be able to start the engine. A maximum of 8 ignition keys can be programmed for the vehicle. The PATS control function in the PCM enters the Anti-Scan Mode if an unprogrammed ignition key (of the correct shape) is used to start the engine.

NOTE: If an unprogrammed key is used, reading the code of any subsequent key is blocked for 20 seconds. During these 20 seconds, the vehicle engine cannot be started with any ignition key. To exit the 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 the code of the coded ignition key and controlling the activation of the engine and starter. The PATS control function initiates the key request sequence when the ignition switch is turned to the RUN or START position.

Transmitter module

The transmitter module communicates with the encoded ignition key. This module is located on the casting of the ignition key cylinder and has an antenna connected to a small electronic module. Each time the vehicle is started, the transmitter module reads the identification code of the encoded ignition key and sends the data to the PATS control function located in the PCM. No re-initialization is required when removing or installing a new PATS transmitter.

PATS objective function

In vehicles equipped with 1.8 DI diesel engines, the high pressure fuel pump has a pump control unit (PCU) (PATS target function). The PATS control function in the PCM communicates with the PCU to arm or disable the engine. The PCU must receive the required arming signal sequence from the PCM via the CAN network within 1 second after the engine is started or before the engine is switched off. The PATS control function and the PCU exchange security codes when they are installed together, after which they form a matched pair. These exchanged security codes are stored in memory even if the vehicle battery is disconnected. Therefore, after exchanging these security codes, these modules will not function in other vehicles. If the PCM or PCU is replaced, special diagnostic procedures must be performed using the FDS 2000. All PATS components must be functional before starting the engine is allowed. If any of the components are not working properly, the vehicle will not start and the anti-theft alarm indicator lamp will flash a fault code.

Anti-theft alarm system indicator light

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

J1850 Communication Network

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

Starter relay

The starter relay is also used as a secondary means of immobilizing the vehicle engine. The relay is disabled if the PATS system cannot read the code of the coded ignition key with the ignition switch in the ON position. However, the system will not store a DTC or flash the code with the anti-theft alarm indicator lamp if a correctly coded ignition key is read but a fault occurs in the starter relay circuit. Refer to Section 303-06 for additional information. The relay is unlocked when the PATS control function reads the code of the correctly coded ignition key with the ignition switch in the ON position. The PATS system will activate and prevent the vehicle engine from starting if the following is detected: