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

WARNING: This page is about a different car, the 2018 Ford EcoSport. However, it is still accessible from the selected car via links, so may be relevant.

PATS

The PATS function is controlled by the BCM and the PCM.

When the START/STOP button is pressed, a voltage signal is sent to the BCM. When the BCM detects the START/STOP button is pressed, it begins the key initialization sequence by activating the PATS center antenna, PATS front antenna, and keyless entry rear antenna. Each antenna transmits a low frequency signal with an approximate range of 1m (3ft). The passive key activates if it is within range of the antennas. The BCM is able to determine the passive key location (inside or outside the vehicle) based on the input from the antennas.

When the passive key activates, it sends the PATS identification code to the BCM via a high frequency signal. The BCM interprets the high frequency signal from the passive key.

If a programmed passive key is detected inside the vehicle, the BCM transitions the ignition from OFF to ON.

When the ignition transitions from OFF to ON and the modules initialize, the PCM sends a challenge request to the BCM. The BCM 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 RKE system share operation of several components including the passive keys and BCM.

If there is a concern with either of these components, the PATS and the RKE system are both affected.

In the event of a no start, place a programmed passive key in the backup location to allow the vehicle to start. The PATS center antenna activates the passive key when the START/STOP button is pressed in the event the batteries are depleted within the passive key.

If available as a selection on the diagnostic scan tool, the passive start feature is a programmable parameter and can be enabled/disabled. If the feature is disabled, the features to passively enter and start the vehicle are inoperative. To start the vehicle, the passive key must be placed in the backup starting location.

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