419-01C Passive Anti-Theft System (PATS) - Vehicles With: Keyless Entry and Push Button Start	2014 Fiesta
Description and Operation	Procedure revision date: 03/8/2013

Passive Anti-Theft System (PATS) - System Operation and Component Description

System Operation

System Diagram

Network Message Chart

RFA Module Network Input Messages

Broadcast Message	Originating Module	Message Purpose
PATS control command	PCM	The PCM sends the RFA module a challenge request for a valid ID.

PCM Network Input Messages

Broadcast Message	Originating Module	Message Purpose
PATS start request target data	RFA module	The response from the RFA module supplying the PCM challenge ID. If the RFA module ID response is incorrect, then PATS prevents the vehicle from starting.

PATS

The PATS function is controlled by the RFA module and the PCM .

The RFA module sends voltage 2 signals to the START/STOP push-button ignition switch. When the START/STOP button is pressed, the voltage signals are routed to ground, indicating a button press to the RFA module. When the RFA module detects the START/STOP button is pressed, it begins the key initialization sequence by activating the 3 PATS antennas. Each antenna transmits a low frequency signal with an approximate range of 1 m (3 ft). The passive key activates if it is within range of the antennas.

When the passive key activates, it sends an identification code to the Radio Frequency (RF) receiver via a high frequency signal. The Radio Frequency (RF) receiver interprets the high frequency signal from the passive key and sends the information to the RFA module over a LIN -based circuit.

If a programmed passive key is detected, the RFA module transitions the ignition out of off.

When the ignition transitions out of off and the modules initialize, the PCM sends a challenge request to the RFA module. The RFA module replies and, if the correct identification is received, the PATS disables and allows the vehicle to start. If the PATS prevents the vehicle from starting, a DTC sets in one of the modules.

The PATS and the passive entry system share operation of several components including the passive keys and the Radio Frequency (RF) receiver.

If there is a concern with any of these components, the PATS and the passive entry system may both be affected.

Backup Starting

The vehicle can experience a PATS no start if a failure occurs with:

the PATS front antenna.
the PATS center antenna.
the PATS rear antenna.
the battery in the passive key.
the Radio Frequency (RF) receiver.

In the event of one of these failures, place a programmed passive key in the backup location to allow the vehicle to start. The PATS transceiver activates the passive key when the START/STOP button is pressed.

The PATS transceiver is located in the steering column in the same location as a vehicle equipped without push-button start. If the vehicle does not start normally, place the passive key next to the steering column shroud and attempt to start the vehicle.

The RFA module controls the ignition modes and, in conjunction with the PCM , controls the PATS .

For information on ignition states,
Refer to: Steering Wheel and Column Electrical Components - System Operation and Component Description (211-05 Steering Column Switches, Description and Operation).

PATS Parameter Identifications (PIDs)

In conjunction with Diagnostic Trouble Codes (DTCs), the PATS Parameter Identifications (PIDs) are a useful tool when diagnosing PATS concerns.

RFA Module PID Chart

Acronym	Name	Description
MASTERKEY	Master Key Present	Indicates if the key in the vehicle is a programmed key.
MIN_KEYS	Minimum number of keys required	Minimum number of programmed keys required. This PID always reads 2.
PATSENABL	PATS System Status - Enable Status	Indicates if PATS allows the vehicle to start.
PCM_ID	PCM ID Status Stored	Indicates if there is a PCM ID currently stored into the RFA module.
PCM_VFY	PCM Verify OK	Indicates if the PCM ID received by the RFA module matches the PCM ID stored in the RFA module memory.

PCM PID Chart

Acronym	Name	Description
PATSENABL	Vehicle enable status	Indicates if PATS allows the vehicle to start. Must read enabled for the vehicle to start.

Backup Starting

NOTE: There are certain areas within the vehicle where the passive key may not be detected and the message center displays No Key Detected. If the passive key is in the far outside edges of the interior (such as in a door map pocket or above a sun visor), it may not be detected. Move the passive key to a different location and try to turn the ignition on.

When the vehicle experiences a PATS condition, the Key Not Detected message displays in the message center when the START/STOP button is pressed.

In the event of one of these failures, place a programmed passive key in the backup location next to the PATS transceiver to allow the vehicle to start. When the START/STOP button is pressed, the PATS transceiver activates the passive key and the identification code is sent to the RFA module. The PATS transceiver backup slot is located on the steering column in the same location as a conventional ignition lock cylinder would be.

Key Not Detected Message

NOTE: Some brands/types of mobile phone or laptop computer chargers may cause interference that could lead to a PATS concern if the passive key is within close proximity of the charger. If a concern is observed, move the passive key away from the charger and attempt to turn the ignition on.

There are 2 scenarios in which the No Key Detected message displays in the message center.

The first is when the ignition is off, the START/STOP button is pressed and a programmed passive key is not detected inside the vehicle. If a component failure (such as a dead passive key battery) is causing the No Key Detected message to display, the backup starting method can be used.

The second scenario is when the vehicle is running, the driver exits the vehicle with the programmed passive key and closes the door.

The RFA module activates the 3 PATS antennas to search the inside of the vehicle for a passive key any time a door or the liftgate/luggage compartment lid is opened and then closed with the vehicle running and the first time each drive cycle the vehicle speed exceeds 15 kp/h (9 mph). The No Key Detected message displays in the message center and the horn chirps twice when the ignition is on and a passive key is no longer detected inside the vehicle.

This strategy deters the passive key from being separated from an already running vehicle. If a passive key is no longer in the vehicle, the ignition remains on and the vehicle continues to operate. When the START/STOP button is pressed to turn the ignition off, the ignition can be restarted without a passive key present inside the vehicle for approximately 20 seconds. After 20 seconds have elapsed, a passive key must be present to transition the ignition out of off.

Automatic Engine Idle Shutdown

The automatic engine idle shutdown feature monitors the state of the vehicle to determine when the engine is powered with no user interaction for approximately 30 minutes. Approximately 30 seconds prior to the shutdown, a message displays in the message center to inform the operator a vehicle shutdown is imminent. This includes shutting down the engine and turning the ignition off. When the shutdown occurs, press the brake and START/STOP button to re-start the vehicle.

The conditions required to begin the automatic engine idle shutdown feature are:

power pack enabled (engine running)
brake pedal not pressed
accelerator pedal not pressed
clutch pedal not pressed
transmission in P (park) or N (neutral)
diagnostic scan tool not connected to the vehicle

Once these conditions are met, a time-out starts. When the time-out period ends and none of the listed conditions changed, the automatic engine idle shutdown event occurs.

Component Description

Passive Key

The passive key incorporates both the PATS and the RKE transmitter functions into a single device. The passive key must be located inside the vehicle for the ignition to transition out of off and outside the vehicle for passive entry features. During key programming procedures, the PATS and the RKE transmitter of the passive key are both programmed into the RFA module. The vehicle accepts programming of up to 8 passive keys.

The passive key receives the low frequency signals from any of the 3 PATS antennas. When the passive key is activated by one of the low frequency signals, it sends out a high frequency signal that is received by the Radio Frequency (RF) receiver. The passive key also contains a removable key blade that unlocks the driver door in the event of an electrical failure (such as a drained battery).

PATS Antennas

NOTE: Some brands/types of mobile phone or laptop computer chargers may cause interference that could lead to a PATS concern if the passive key is within a few inches of the charger and the Key Not Detected message displays in the message center. If a concern is observed, move the passive key away from the charger and attempt to transition the ignition on.

There are 3 passive start antennas. The passive start antennas are wired to the RFA module. When activated by the RFA module, they transmit a low frequency signal that activates a passive key.

The passive start antennas are used for the purpose of starting the vehicle or changing the ignition states. When activated, each antenna sends out a low frequency signal with an approximate range of 1 m (3 ft). A programmed passive key must be in range of 1 of the 3 antennas to be detected.

If a passive key is placed in the far outside edges of the interior, such as above a sun visor or in a door map pocket, the vehicle can experience a no-start condition. If the passive key is located in one of these areas and there is a no-start condition, move the passive key out of that area and attempt to start the vehicle. If the key is outside the range of a passive start antenna when the START/STOP button is pressed, the Key Not Detected message displays in the message center.

RFA Module

If the RFA module is replaced, program at least 2 keys and perform a parameter reset with the PCM .

The RFA module requires PMI when it is replaced.

PCM

If the PCM is replaced, perform the parameter reset procedure. There is no need to program keys if the PCM is replaced.

The PCM requires PMI when it is replaced.