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

WARNING: This page is about a different car, the 2022 Ford Transit-350 HD, 2022 Ford Transit-350, 2022 Ford Transit-250, 2022 Ford Transit-150, and 2022 Ford E-Transit. However, it is still accessible from the selected car via links, so may be relevant.

The PATS function is controlled by the BCM, the PCM, ABS, and SOBDMC (if equipped).

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 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 RTM via a high frequency signal. The RTM interprets the high frequency signal from the passive key and sends the information to the BCM over the LIN based circuit.

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 target 1 challenge request, the SOBDMC sends a target 2 challenge request (if equipped), and the ABS module replies to a target 1 challenge request to the PCM. 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, the BCM, and the RTM.

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.

NOTE: 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, ABS, and the SOBDMC (if equipped), controls the PATS.