Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Passive Anti-Theft System (PATS) - System Operation and Component Description: Pats: Notes
The PATS function is controlled by the BCM and the PCM.
When the START/STOP button is pressed, a 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, the PATS rear antenna and both exterior door handle keyless entry 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. 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 valid programmed passive key is detected inside the vehicle, the BCM 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 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, the BCM and the RTM.
If there is a concern with any 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.
The BCM controls the ignition modes and, in conjunction with the PCM, control the PATS.
For information on ignition states, Refer to: Steering Wheel and Column Electrical Components - System Operation and Component Description .
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.